Re: Typing in lost code

[dwight via cctalk]

It is unlikely that no current day OCR will produce an error free listing.
It is possible to train an AI to do this but it requires specific training. It 
must be on the specific machine code and on the same format. Any generic OCR 
will have many errors if the text is hard to read.
The final product must include notes as to things it is not sure about or it 
would be useless. I recovered a listing for the 4004 processor that was printed 
on a ASR33 with ruts on the platen. The right hand 1/4 of letters were missing 
at several locations across the page. Letters such as F and P, as well as 0 and 
C were often not well enough printed to distinguish.
Luckily F and P were often in context relatively easy to determine but 0 and C 
were often use to describe a HEX number. Unlike the text on this page, the 
differences were not always obvious. The final result in working code required 
noting which things were possibly one or the other. The only way to determine 
most of these was by using a simulation of the code. Most all the cases for the 
0 vrs C were that it was a 0, as these were for initializing a pointer base 
number ( context of usage ). In one case it was only through the simulation was 
I able to determine that it was really CC and not 00.
Marking locations of uncertainty was essential to determine where to check the 
program code context.
Any OCR that doesn't include possible options and that isn't trained on that 
particular code is worthless.
Dwight


From: cctalk  on behalf of Noel Chiappa via 
cctalk 
Sent: Sunday, January 23, 2022 9:31 AM
To: cctalk@classiccmp.org 
Cc: j...@mercury.lcs.mit.edu 
Subject: Re: Typing in lost code

> From: Gavin Scott

> I think if I had a whole lot of old faded greenbar etc. ... Someone may
> even have done this already

See:

  https://walden-family.com/impcode/imp-code.pdf

Someone's already done the specialist OCR to deal with faded program listings.

Noel

Re: Typing in lost code

[dwight via cctalk]

Sorry about the double negative.
I was in a hurry as I was supposed to drive over the hill to Santa Cruz for a 
couple hours.

"It is unlikely that no current day OCR will produce an error free listing."
Should have read:
"It is unlikely that any current day OCR will produce an error free listing."

I agree with Chuck. A computer code listing cannot tolerate a single mistake in 
a number. I recall recovering data from cassette tapes were the tape stuck to 
the capstan and got folds. Most of the code was in BASIC so had quite a bit of 
redundancy for the program flow. Luckily, there were few damaged segments with 
numeric values. The tapes had check sums that helped quite a bit. It is not so 
in typed listings.
As I stated, the code I recovered for the 4004 code would have been lost if I'd 
not understood the purpose and run the simulation of the code, stopping to see 
what alternate values did to the execution of the code. It was over 3K of code. 
Quite a bit for a 4004. It was intended to be loaded into 13 1702A Eproms. 
There were over 30 points in the code that needed to be resolved.
Dwight


From: cctalk  on behalf of dwight via cctalk 

Sent: Sunday, January 23, 2022 10:06 AM
To: cctalk@classiccmp.org 
Subject: Re: Typing in lost code

It is unlikely that no current day OCR will produce an error free listing.
It is possible to train an AI to do this but it requires specific training. It 
must be on the specific machine code and on the same format. Any generic OCR 
will have many errors if the text is hard to read.
The final product must include notes as to things it is not sure about or it 
would be useless. I recovered a listing for the 4004 processor that was printed 
on a ASR33 with ruts on the platen. The right hand 1/4 of letters were missing 
at several locations across the page. Letters such as F and P, as well as 0 and 
C were often not well enough printed to distinguish.
Luckily F and P were often in context relatively easy to determine but 0 and C 
were often use to describe a HEX number. Unlike the text on this page, the 
differences were not always obvious. The final result in working code required 
noting which things were possibly one or the other. The only way to determine 
most of these was by using a simulation of the code. Most all the cases for the 
0 vrs C were that it was a 0, as these were for initializing a pointer base 
number ( context of usage ). In one case it was only through the simulation was 
I able to determine that it was really CC and not 00.
Marking locations of uncertainty was essential to determine where to check the 
program code context.
Any OCR that doesn't include possible options and that isn't trained on that 
particular code is worthless.
Dwight


From: cctalk  on behalf of Noel Chiappa via 
cctalk 
Sent: Sunday, January 23, 2022 9:31 AM
To: cctalk@classiccmp.org 
Cc: j...@mercury.lcs.mit.edu 
Subject: Re: Typing in lost code

> From: Gavin Scott

> I think if I had a whole lot of old faded greenbar etc. ... Someone may
> even have done this already

See:

  https://walden-family.com/impcode/imp-code.pdf

Someone's already done the specialist OCR to deal with faded program listings.

Noel

Re: Retro Chip Tester Pro, done!

[dwight via cctalk]

I hope you are not thinking it would test an Intel 4004 or a 8008? That would 
be a stretch. For the 4004, there is only a narrow range of frequencies it runs 
under. I'm not that familiar with the 8008 but suspect it has similar 
restrictions. Both use dynamic registers. Both use PMOS voltage levels( 15V ). 
A 4008 RAM chip is not the same as an intel 4008 chip.
It is conceivable to use a logic tester to test a i4004 but it would be a lot 
of effort. Each instruction does unique operations inside of the i4004. One 
would have to have 256^2 inputs to fully test a i4004 from the pins. Even then 
there are a similar number of replies that would have to be checked. One could 
at best have a simple confidence test that it appeared to be working, as most 
failures of IC cause complete failure of the chip. Even Intel never fully 
tested parts going out the door. Even for a processor as simple as the 4004, a 
complete test is not practical. There are not test circuits built into it 
either.
Erturk Kolcalar makes a retro processor exerciser. It basically runs through a 
USB port from a PC. In its current form, it can't fully test a i4004 because it 
doesn't meet the proper frequency ( some will work but others won't, but still 
be functional i4004s ). It runs code loaded from the PC. He currently has the 
code for the Busicom calculator running.
I don't recall if he has one for the 8008?
Dwight



From: cctalk  on behalf of ED SHARPE via cctalk 

Sent: Monday, February 7, 2022 5:44 PM
To: cctalk@classiccmp.org ; cctalk@classiccmp.org 

Subject: Re: Retro Chip Tester Pro, done!

does it test 4004  and 8008

In a message dated 2/7/2022 6:32:24 PM US Mountain Standard Time, 
cctalk@classiccmp.org writes:
You may recall that, a few weeks ago, I requested parts help (shoppingbaskets) 
for the Retro Chip Tester Pro that I got for Christmas.  Well, today's 
mailbrought the last few parts and I have finished and tested it.  Wow!  The 
only thing that itdoesn't do is slice bread.  It's great.  I've put up a few 
pictures here:   http://wsudbrink.dyndns.org:8080/images/RCTPro/   I got the 
4008 and 1702 adapters with it, but I'm pretty sure that I willget the rest 
over the next month or so.  This is the latest HW version with the latest 
releasesoftware.   Bill S.   PS: Thanks to everyone that helped with parts.   
-- This email has been checked for viruses by Avast antivirus 
software.https://www.avast.com/antivirus

Re: ID UV erasable PROMS used on an IBM PC board?

[dwight via cctalk]

The dies look to have consistent wire bonding. That would mean they are one of 
the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. 
The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My 
guess is that they are 2732s. You might use a microscope and look at the edges 
of the dies. They often have the die type in the metal layers around the edge 
some place. Avoid using florescent ring lights as a large amount of UVC leaks 
from these. White LED are or incandescent lights.
Also power it up and note which pins look to have signals. if any of the lines 
have what looks like a constant voltage measure it to the nearest .01 volts if 
you can. That will help determine if it is driven by a signal or a hard tied 
wire. Lower left and upper right should be ground and power pins.
Dwight



From: cctalk  on behalf of D. Resor via cctalk 

Sent: Sunday, March 20, 2022 6:53 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' 
Subject: ID UV erasable PROMS used on an IBM PC board?

I cannot find a datasheet by any of the numbers silkscreened on these ICs.

Could these be proprietary IBM P/N numbers?

https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0

No need for a Dropbox account, close the login pop up and you can view the
image.

Thanks

Don Resor

Re: ID UV erasable PROMS used on an IBM PC board?

[dwight via cctalk]

Yes, you are correct. I'm a bad counter. I knew a 2732 was a 24 but suffer from 
brain rot. Still it is likely a standard Intel part. At most it may have a pin 
swap on something like a select pin.
Measuring the pins, will tell which pins are tied and which are active.
Dwight


From: cctalk  on behalf of Paul Berger via 
cctalk 
Sent: Monday, March 21, 2022 5:19 PM
To: dwight via cctalk 
Subject: Re: ID UV erasable PROMS used on an IBM PC board?

They won't be 2732 as the EPROM in the picture has 28 pins, but 2732 is
a 24 pin package 2764, 27128, 27256 and 27512 are all in 28 pin packages.

The 8519602 does look like an IBM house number but unfortunately it is
not listed in the cross reference I have .

I would agree it should be fairly easy to figure out what they are by
looking at the circuitry surrounding them.  The unpopulated U3 position
beside the EPROM looks like it might be for another EPROM and it looks
to have pins 26,27,and 28 all tied together on everything larger than a
2764, pin 26 is A13 so my guess would be 2764.  If you read a 2764 as a
27128 the upper and lower halves of the image will be identical because
the A13 pin is not connected on a 2764 so you would effectively read the
EPROM twice.  Pin 26 tied high would eliminate anything larger than a 2764.

Paul.


On 2022-03-21 20:49, dwight via cctalk wrote:
> The dies look to have consistent wire bonding. That would mean they are one 
> of the standard EPROMs made by Intel, just preprogrammed by Intel before 
> shipping. The numbers wouldn't be intel numbers they would be IBMs inventory 
> numbers. My guess is that they are 2732s. You might use a microscope and look 
> at the edges of the dies. They often have the die type in the metal layers 
> around the edge some place. Avoid using florescent ring lights as a large 
> amount of UVC leaks from these. White LED are or incandescent lights.
> Also power it up and note which pins look to have signals. if any of the 
> lines have what looks like a constant voltage measure it to the nearest .01 
> volts if you can. That will help determine if it is driven by a signal or a 
> hard tied wire. Lower left and upper right should be ground and power pins.
> Dwight
>
>
> 
> From: cctalk  on behalf of D. Resor via cctalk 
> 
> Sent: Sunday, March 20, 2022 6:53 PM
> To: 'General Discussion: On-Topic and Off-Topic Posts' 
> Subject: ID UV erasable PROMS used on an IBM PC board?
>
> I cannot find a datasheet by any of the numbers silkscreened on these ICs.
>
> Could these be proprietary IBM P/N numbers?
>
> https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0
>
> No need for a Dropbox account, close the login pop up and you can view the
> image.
>
> Thanks
>
> Don Resor
>
>

Re: ID UV erasable PROMS used on an IBM PC board?

[dwight via cctalk]

It is true that the glass blocks most of the UVC from florescent lamps. The key 
word here is "most". It is not a 100% block.
When looking at aged data in EPROMs one should error on the side of caution.
As an example, I have a pole lamp that I use a standard florescent bulb, with 
the typical spiral of 3 turns. I used it for about 4 hours a day for about a 
month when I bumped into the lamp shade.
It crumbled into pieces. At the base where the lamp shade was protected from 
direct light of the lamp, the plastic seemed to be of full strength, even 
though the temperature was higher at the base.
I don't know the intensity of the various levels of UV at different frequencies 
leaking from the lamp. I do know that it takes a specific high frequency of UV 
in the UVC range as a minimum to erase EPROMs. This plastic may be sensitive to 
UV closer to the visible spectrum.
I'm only saying that one should use a lamp that has zero UVC as apposed to a 
lamp that has a filter reduced level of UVC.
Years ago, I won a bet by allowing an EPROM to sit exposed for 3 months in an 
industrial setting, using florescent tube lighting. It did not erase any of the 
data in that condition. I suspect it had some effect but unlikely much more 
than that lost by cosmic rays over the same period of time.
Holding an aged EPROM about 2 inches from a florescent lamp is still not 
something that I'd bet on.
Dwight




From: D. Resor 
Sent: Tuesday, March 22, 2022 2:40 AM
To: 'dwight' ; 'General Discussion: On-Topic and Off-Topic 
Posts' 
Subject: RE: ID UV erasable PROMS used on an IBM PC board?


There are a few other problems.



The power supply does not power up.  Three of it’s four voltages are missing 
(+5vdc, +8.5vdc, +13vdc).  With no connections to the power supply board, the 
+5vdc measures 4.92vdc while the other two voltages are still zero volts.



The second issue I found upon removing the driver and processor board is 
moisture had entered the typewriter’s electronics and the connector between the 
two boards has corrosion on many of the pins and on the PWB near the connector.



I do not have access to a microscope.



I know it has been explained to me elsewhere that UV exposure from florescent 
lamps can erase the proms.  The way I understand is the glass of the florescent 
lamp filters out any UV radiation (as does the piece of glass mounted in front 
of quartz halogen lighting).  In order that a UV lamp can operate correctly the 
tube must be made of quartz, not glass.



Am I wrong here?



Don Resor



From: dwight 
Sent: Monday, March 21, 2022 4:50 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' ; 
D. Resor 
Subject: Re: ID UV erasable PROMS used on an IBM PC board?



The dies look to have consistent wire bonding. That would mean they are one of 
the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. 
The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My 
guess is that they are 2732s. You might use a microscope and look at the edges 
of the dies. They often have the die type in the metal layers around the edge 
some place. Avoid using florescent ring lights as a large amount of UVC leaks 
from these. White LED are or incandescent lights.

Also power it up and note which pins look to have signals. if any of the lines 
have what looks like a constant voltage measure it to the nearest .01 volts if 
you can. That will help determine if it is driven by a signal or a hard tied 
wire. Lower left and upper right should be ground and power pins.

Dwight







From: cctalk  on behalf of D. Resor via cctalk 

Sent: Sunday, March 20, 2022 6:53 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' 
Subject: ID UV erasable PROMS used on an IBM PC board?



I cannot find a datasheet by any of the numbers silkscreened on these ICs.

Could these be proprietary IBM P/N numbers?

https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0

No need for a Dropbox account, close the login pop up and you can view the
image.

Thanks

Don Resor

Re: ID UV erasable PROMS used on an IBM PC board?

[dwight via cctalk]

Years ago when I was at Intel, they would take EPROMs that had only a few 
defects and attempt to program them with specific applications. They would then 
usually paint the window black and put on that particular product number. When 
we needed EPROMs in the lab, we would take a pile of these that were no longer 
used and scrape the paint off the window. Some would take the desired program 
and some wouldn't.
I suspect that they can fuse identify specific bad EPROMs to use for such 
harvesting. The fused value may be laser blown as well. My guess is that that 
is the reason for the different ID number. If it will take pre-programming with 
a particular data, it is worth harvesting.
This way they can find value in an otherwise unsellable product. I doubt the 
harvesting methods have changed much over the years.
Dwight

From: cctalk  on behalf of Paul Berger via 
cctalk 
Sent: Tuesday, March 22, 2022 1:14 PM
To: D. Resor via cctalk 
Subject: Re: ID UV erasable PROMS used on an IBM PC board?

I can tell you what some of the chips are on the power supply board, but
the list I have is mostly TTL parts

1582684 LM324
1582606 74LS74  F/F D-TYPE DUAL +E/T
2392122 7417BUF/DVR HEX O/C (TPD0 30NS)
8272147 74LS05  INV HEX O/C

Aside from the house numbering of parts which is not unique to IBM, IBM
had their own foundry for many years so you will encounter custom  parts
for which there is no industry equivalent, this is also not unique to
IBM, I have some HP computers that many of the parts are house numbered,
and HP also manufactured their own chips so there are some parts that
are unobtanium as well.

Paul.

On 2022-03-22 06:40, D. Resor via cctalk wrote:
> There are a few other problems.
>
> The power supply does not power up.  Three of it's four voltages are missing
> (+5vdc, +8.5vdc, +13vdc).  With no connections to the power supply board,
> the +5vdc measures 4.92vdc while the other two voltages are still zero
> volts.
>
> The second issue I found upon removing the driver and processor board is
> moisture had entered the typewriter's electronics and the connector between
> the two boards has corrosion on many of the pins and on the PWB near the
> connector.
>
> I do not have access to a microscope.
>
> I know it has been explained to me elsewhere that UV exposure from
> florescent lamps can erase the proms.  The way I understand is the glass of
> the florescent lamp filters out any UV radiation (as does the piece of glass
> mounted in front of quartz halogen lighting).  In order that a UV lamp can
> operate correctly the tube must be made of quartz, not glass.
>
> Am I wrong here?
>
> Don Resor
>
> From: dwight 
> Sent: Monday, March 21, 2022 4:50 PM
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> ; D. Resor 
> Subject: Re: ID UV erasable PROMS used on an IBM PC board?
>
> The dies look to have consistent wire bonding. That would mean they are one
> of the standard EPROMs made by Intel, just preprogrammed by Intel before
> shipping. The numbers wouldn't be intel numbers they would be IBMs inventory
> numbers. My guess is that they are 2732s. You might use a microscope and
> look at the edges of the dies. They often have the die type in the metal
> layers around the edge some place. Avoid using florescent ring lights as a
> large amount of UVC leaks from these. White LED are or incandescent lights.
> Also power it up and note which pins look to have signals. if any of the
> lines have what looks like a constant voltage measure it to the nearest .01
> volts if you can. That will help determine if it is driven by a signal or a
> hard tied wire. Lower left and upper right should be ground and power pins.
> Dwight
>
>
>_
>
> From: cctalk  on behalf of D. Resor via
> cctalk 
> Sent: Sunday, March 20, 2022 6:53 PM
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> 
> Subject: ID UV erasable PROMS used on an IBM PC board?
>
> I cannot find a datasheet by any of the numbers silkscreened on these ICs.
>
> Could these be proprietary IBM P/N numbers?
>
> https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0
>
> No need for a Dropbox account, close the login pop up and you can view the
> image.
>
> Thanks
>
> Don Resor
>
>

phishing increase lately

[dwight via cctalk]

I've been getting a bunch of "release of lien waiver"
messages lately.
I've not been opening the click bate. I'm just wondering if anyone else is 
getting them.
I don't know what nasty is attached as I don't have a secure system to look at 
it.
Dwight

Re: phishing increase lately

[dwight via cctalk]

I was just wondering if I was the only one. It may have been through someplace 
else I've been at.
I just wanted to send the warning. I've seen 3 in the last day.
I must be on someone's list.
Dwight


From: Paul Koning 
Sent: Thursday, April 14, 2022 10:56 AM
To: dwight ; cctalk@classiccmp.org 
Subject: Re: phishing increase lately

What, on this list?  I haven't seen any of that.

I get a large amount of dishonest mail; much of it is caught by my "send this 
immediately to trash without reading it" filter rules.  Like you, I have no 
idea what's attached, simply because I have no interest in investigating the 
machinations of criminal elements on the net.

paul

> On Apr 14, 2022, at 1:47 PM, dwight via cctalk  wrote:
>
> I've been getting a bunch of "release of lien waiver"
> messages lately.
> I've not been opening the click bate. I'm just wondering if anyone else is 
> getting them.
> I don't know what nasty is attached as I don't have a secure system to look 
> at it.
> Dwight
>

Re: Advice on Desoldering an IC

[dwight via cctalk]

Sometimes the IC has been installed with the pins under tension. This is 
typical of machine inserted ICs. When the solder is loose, bend the pin away 
from the side it is pressed against. Do this carefully, don't over bend. You 
want it to center in the hole. I recommend doing this with a separate iron than 
the desoldering tool, so you can see what you are doing. Once the pin is nicely 
centered in the hole use the desoldering tool to suck the solder out.
Make sure to always use a clean tip. An oxidixed tip will require excess 
pressure to transfer heatand damage the trace. Keep the solder shinny with a 
spung or soft metal wool. Do mot use a hard metal to clean an iron clad tip or 
it will damage the iron and rot it from the inside 🙁
When not using the iron but leaving it hot, always leave a blob of solder so 
that it won't have a thin oxide coating that is hard to remove. KEEP A CLEAN 
TIP!
After sucking the solder with the tool, with a small screw driver, give the pin 
a slight sideways pressure and let the screw driver slip off the pin. It should 
make a plink sound or a momentary ring. This is something that you'll just have 
to learn the sound of. If it doesn't sound right it means it isn't free of the 
sides. Add solder and try to bend the pin.
Often the body side of the IC will have a tiny film of solder right where the 
IC sits on the trace. If this is just the tiny amount to solder, one can break 
it loose with a pair of short needle nose pliers, By squeezing the two sides of 
the IC together. Don't expect to break loose a large blob.
Of course, if you expect to throw the IC away, use sharp pointed dikes to cut 
the pins at the package and pull each pin individually while the solder is hot. 
Use a small vice to hold the board so you can work from both sides. Tweezers 
are best but heat the solder first and when hot grab the pin from the top. Work 
quickly while the solder is hot.
You may need to refill the pin with fresh clean solder. Old oxidized solder 
does not remove easily. Use separate rosin flux if you have it ( not plumber 
flux!! ).
Like I said earlier, use a really clean tip. It should be shinny before trying 
to heat the board. It is hard to do with the higher temperature solders. There 
is some low temperature stuff you can use to remove solder more quickly.
I like using a large manual plastic solderpulit. Some like to use solder wick. 
The solder removal suckers are often hard to keep the tip clean. If you have to 
press hard on the tip to the work, the tip is not clean. It does help to have 
some really tiny flux core solder to touch right at the junction of the iron 
and work to start the heat transfer. Never use force to get the heat to start 
to transfer! Clean tip and a quick touch with solder is all that is needed.
When you are not using the iron for some time, but leaving it on, add a thicker 
blob of solder on it so it doesn't get a thin hard to clean oxide on it. KEEP 
YOUR TIP FREE OF THIN OXIDE!
Dwight




From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Friday, April 15, 2022 10:49 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Subject: Advice on Desoldering an IC

I am trying to remove an IC from my PDP 11/24 CPU, a DS8641. I am really
struggling to desolder it. I am using the technique of applying fresh solder
and then removing it. But after multiple cycles of this I think I am
starting to damage the PCB.



I am using a fairly cheap desoldering station (this one
https://cpc.farnell.com/duratool/d00672/desoldering-station-uk-eu-plug/dp/SD
01384?st=duratool%20desoldering). Its spec in terms of vacuum pressure is
equivalent to that of the professional Hakko ones though. I am also trying a
hand desoldering pump. None of these are able to clear many of the holes of
solder, although some are doing better than others. Nevertheless, the IC
remains stubbornly unmoving.



Are there any tips for removing ICs?



Thanks



Rob

Re: cleaning up edge connectors

[dwight via cctalk]

Once the corrosion is removed I recommend using DC-4 on the connections. It 
will protect the surfaces and keep great electrical connections. It is a 
silicon grease that is non-conductive but keeps the surface clean and improves 
metal to metal electrical contact. It doesn't allow oxides to build at the 
contact surfaces.
It has measurable improvements of even gold on gold. I've used it on solder to 
solder as well other dissimilar metals with good results.
I've used it on high current connections to reduce resistive heating up to 1000 
amperes.
Dwight

Re: cleaning up edge connectors

[dwight via cctalk]

Yep. I didn't know it was now made by someone else. Also look at McMaster-Carr. 
You might get a better price.
Dwight



From: Ali 
Sent: Saturday, April 30, 2022 3:23 PM
To: 'dwight' ; 'General Discussion: On-Topic and Off-Topic 
Posts' 
Subject: RE: cleaning up edge connectors

> Once the corrosion is removed I recommend using DC-4 on the
> connections. It will protect the surfaces and keep great electrical
> connections. It is a silicon grease that is non-conductive but keeps
> the surface clean and improves metal to metal electrical contact. It
> doesn't allow oxides to build at the contact surfaces.
> It has measurable improvements of even gold on gold. I've used it on
> solder to solder as well other dissimilar metals with good results.
> I've used it on high current connections to reduce resistive heating up
> to 1000 amperes.


Dwight,

Is this what you are talking about:

https://www.aircraftspruce.com/catalog/cspages/dc4.php

-Ali

Recent purchase of NIC-80 computer.

[dwight via cctalk]

Hi All
 There was a Nicolet computer purchased recently on ebay:
https://www.ebay.com/bfl/viewbids/363826255294?item=363826255294&rt=nc&_trksid=p2047675.l2565
Looking at the buyers history, it looks like it was purchased by a collector.
Bob Rosenbloom and I are wondering if anyone know who might have purchased it 
and if they are expecting to restore it to operational status?
These are an interesting computer being that it is a 20 bit word. It was also 
designed specifically to do FFT's with specialized instructions like bit 
reversing and hardware multiply and divide.
It also has an built in A/D that can have different bandwidth, depending on 
sample size.
The original design was for NMR chemical analysis. But was especially useful 
for acquiring repeating sampled evens that had low signal to noise because of 
its hardware built in analog acquisition capable of multiple samples to 
accumulate multiple pass without requiring action by the processor.
We were hoping to see if the person that acquired the computer was interested 
in restoring it to operational status. Bob and I have accumulated a significant 
amount of both hardware and software for this computer.
I am also quite good at trouble shooting this design as I original brought my 
NIC-80 back to life without schematics (we now have a schematic set, thanks to 
a fellow in Australia that had a set of manuals ).
The person that bought it would have been relatively close in Wisconsin, as it 
was a pick up local item.
Thanks
Dwight

Re: Recent purchase of NIC-80 computer.

[dwight via cctalk]

Hi Paul
 It may be a little slow for DSP. Its main thing was that the acquisition 
didn't require and processor time. It was designed before uPs. ( not counting 
what was used in the F16's ).
It is fun because it has a full front panel to toggle in a bootstrap. Then one 
can load with the serial. Mine also has a floppy drive ( something is broken 
right now ). I also have a Diablo 30 for it but haven't had time to play with 
it. The floppy was working at one time. I had to rewrite the low level code for 
the floppy from code I had for the diablo.
Bob has no mass storage yet. It is on his list of projects.
Dwight



From: Paul Koning 
Sent: Thursday, May 12, 2022 10:15 AM
To: dwight ; cctalk@classiccmp.org 
Subject: Re: Recent purchase of NIC-80 computer.



> On May 12, 2022, at 1:03 PM, dwight via cctalk  wrote:
>
> Hi All
> There was a Nicolet computer purchased recently on ebay:
> https://www.ebay.com/bfl/viewbids/363826255294?item=363826255294&rt=nc&_trksid=p2047675.l2565
> Looking at the buyers history, it looks like it was purchased by a collector.
> Bob Rosenbloom and I are wondering if anyone know who might have purchased it 
> and if they are expecting to restore it to operational status?
> These are an interesting computer being that it is a 20 bit word. It was also 
> designed specifically to do FFT's with specialized instructions like bit 
> reversing and hardware multiply and divide.

That may simply be a quite ordinary DSP processor.  Hardware multiply and in 
particular single cycle mul + add are typical DSP operations because you need 
them for FIR filters, one of the most common applications of a DSP.  And of 
course bit reverse for FFT, which has the nice property of being very easy in 
hardware.

paul

Re: Nicolet Computer interest

[dwight via cctalk]

It may have a processor inside. if it is the one I think it is, it uses 2900 
ALUs.
If you can send a picture I may be able to tell.
Dwight

From: cctalk  on behalf of dancohoe--- via 
cctalk 
Sent: Thursday, May 12, 2022 1:45 PM
To: 'dwight via cctalk' 
Subject: Nicolet Computer interest

Hi Dwight,

In 2010 I purchased a Nicolet LAS 12/70 Data and Signal Processor System box
on ebay.  I hoped it was a Nicolet computer but then could find nothing
online about it.

It's on the shelf here and I've never looked inside to see what's there.
It's ridiculously heavy.

I don't know if there's anything useful from it for you guys, but I can take
a look at what is on the inside and report back.

Regards,  Dan

Re: Replacement for a DEC 7474 Chip

[dwight via cctalk]

What ever you do, don't use a Fairchild part. When I worked for Intel in the 
80's, we finally band using Fairchild for any latching device. They failed on 
pullup current, even when the parts were sent back and they claimed they were 
good. We just gave up on them, we couldn't hold production while they figured 
it out.
We had a similar problem with PowerOne, a manufacture of power supplies. Since 
it was a custom supply, we had to send someone to their plant to fix their 
final test.
Dwight



From: cctalk  on behalf of Nigel Johnson Ham via 
cctalk 
Sent: Saturday, May 14, 2022 10:50 AM
To: Paul Koning via cctalk 
Subject: Re: Replacement for a DEC 7474 Chip

AFAIR LS can only drive one unit TTL load.

I may have some 7474, even of that vintage, if you cannot find any
anywhere else.

cheers,

Nigel


Nigel Johnson, MSc., MIEEE, MCSE VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
Skype:  TILBURY2591


On 2022-05-14 13:48, Paul Koning via cctalk wrote:
>
>> On May 14, 2022, at 1:41 PM, John Robertson via 
>> cctalk  wrote:
>>
>> On 2022/05/14 10:11 a.m., Rob Jarratt via cctalk wrote:
>>> Hello,
>>>
>>> I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
>>> 7474 D flip flop. The problem is I don't know which modern series
>>> would be the best one to replace it with. I am sure I have seen a list
>>> somewhere of modern equivalents for some DEC chip numbers, but I can't
>>> remember where.
>>>
>>> If it helps at all, on the PDP 11/24 printset it is E78 on page K6 of the
>>> schematic (p157 of the PDF).
>>>
>>> Picture of the failed chip here:
>>> https://rjarratt.files.wordpress.com/2022/05/damaged-dec-7474-4_li.jpg
>>>
>>> Can anyone tell me what the best modern equivalent is likely to be?
>>>
>>> Thanks
>>>
>>> Rob
>>>
>> You are stuck with using an original 7474 family assuming this is driving 
>> other early TTL. 74LS74, and others simply don't have the drive capability 
>> to work.
> I know LS has less fanout, but is it not able to drive plain 74xx at all?  
> That doesn't sound right.  If the circuit in question runs near the fanout 
> spec of plain 74 the yes, 74LS won't work.
>
> Spec sheets and the actual schematic will give a definitive answer.
>
>paul
>
>

Re: PL/M & CP/M

[dwight via cctalk]

I'm relatively sure PL/M was written by Gary Kildall.
I believe it was originally used on minis ( not sure which one ) but was later 
ported to the 8080 under ISIS. One might notice the similarities of ISIS to 
CP/M.
Dwight


From: cctalk  on behalf of Chuck Guzis via 
cctalk 
Sent: Tuesday, June 7, 2022 9:05 AM
To: Hector Peraza via cctalk 
Subject: Re: PL/M & CP/M

On 6/7/22 00:30, Hector Peraza via cctalk wrote:

> In the late 80's I disassembled a PL/M compiler I got in paper tape and
> ported it to CP/M. Then stored it in a cassette tape, then lost it, then
> about 8 years ago found it again and recovered it. The compiler had no
> indication whatsoever of who wrote it, but with the help of Mr. Emmanuel
> Roche from comp.os.cpm it's origin was traced back to Norsk Data's
> PL/Mycro compiler for their Mycro-1 8080 machine. It is a one-pass
> compiler (the key to its identification), appeared to be written
> directly in 8080 assembly, and produces hex or binary output. I never
> made it available anywhere, except for the copy I gave to Mr. Roche and
> IIRC to Mark Ogden too. Is that the one you mean? The only other PL/M
> compiler I know about that ran on 8-bit hardware, besides Intel's, was
> PLMX but I don't now the history behind it.
>
Back in the late 70s I sampled (for my employer) MP/M 1.0.  One of the
things that came with the OEM kit was DRI's PL/I compiler.  I'd become
acquainted with PL/I under DOS/360 and was surprised to see PL/I for 8
bit machines.  What was most surprising was that it was a pretty
complete D-level implementation on the 8080 (I ran it on 8085),
including the preprocessor (I can recall wishing that C had a similarly
capable preprocessor back then--not just a bunch of conditionals and the
#define statement).

I recall that DRI at the time was pushing its ISV program, with the hope
that PL/I might be sufficiently platform-independent.

--Chuck

[cctalk] Re: "Revival" of a dedicated Micropolis webpage on internet

[dwight via cctalk]

Maybe it is on a size reduction.
Dwight


From: geneb via cctalk 
Sent: Saturday, August 20, 2022 7:47 AM
To: Liam Proven via cctalk 
Cc: geneb 
Subject: [cctalk] Re: "Revival" of a dedicated Micropolis webpage on internet

On Wed, 17 Aug 2022, Liam Proven via cctalk wrote:

> On Tue, 16 Aug 2022 at 23:51, Fred Cisin via cctalk
>  wrote:
>>
>> 1) because they need to keep reinforcing until the very last SA400 is
>> buried.
>>

Fred, Don't forget the SA390 in every Disk II. ;)

> I had to look up SA400. I'm too young.
>
> The Smithsonian has one. They say it's a 3¼ inch drive.
>
> https://www.si.edu/object/microcomputer-peripheral-shugart-sa400-disk-drive:nmah_334325
>

Now THAT is just tragic.

g.

--
Proud owner of F-15C 80-0007
http://www.f15sim.com - The only one of its kind.
http://www.diy-cockpits.org/coll - Go Collimated or Go Home.
Some people collect things for a hobby.  Geeks collect hobbies.

ScarletDME - The red hot Data Management Environment
A Multi-Value database for the masses, not the classes.
http://scarlet.deltasoft.com - Get it _today_!

[cctalk] Re: Flipping an 8" diskette

[dwight via cctalk]

When punching holes in the envelope I've always had a piece of thin cardboard 
between the back of the punch and the disk. I've never had a problem this way.
I damaged a disk once with the punch and the lesson was learned.
You just cut the cardboard  to slip conveniently in the center hole, between 
the disk and the envelope.
Dwight

From: Mike Stein via cctalk 
Sent: Thursday, September 1, 2022 7:39 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: Mike Stein 
Subject: [cctalk] Re: Flipping an 8" diskette

Flipping disks to use both sides in a single-side drive was really only
feasible in Commodore and similar drives that did not rely on an index hole
for locating the data on the disk; the notch was to allow writing to the
disk and had to be added on the opposite edge.

To use a flipped 5 1/4" disk in any other drive requires punching holes for
the index sensor in the opposite location, as well as the write (un)protect
notch; this can be tricky and it's easy to damage the actual 'cookie'
unless you remove it first.

All 8" drives use an index hole and also require punching corresponding
index holes but, as Jonathan points out, it's a little more complicated
because  the original location of the hole is different depending on
whether the disk is single- or double-sided .

On the other hand, you don't have to add a notch on an 8" drive unless you
want to write-protect it; the notch acts the reverse of the 5 1/4" notch,
i.e. notch=protect, no notch=write enabled.

Finally, there's the issue of the medium itself; if you're flipping
single-sided disks the early 8" disks are more likely to have flaws on the
unused side than the later 5 1/4" diskettes.

m

On Thu, Sep 1, 2022 at 4:10 AM Liam Proven via cctalk 
wrote:

> Someone on Fesse Bouc just found a sealed box of SS/SD 8" floppies in
> their garage.
>
> Most FB types are too young to know 8" disks existed, of course.
>
> Someone suggested punching a notch in them and using both sides.
>
> Was that even possible on 8" disks?
>
> (TBH single-sided actually-floppy floppies are before my time and I
> never used 'em. When they were on low-end American 8-bit home
> computers, this impecunious young Brit couldn't afford floppy drives
> at all. By the time I could, 5.25" DS/DD was the cheapest drive and
> cheapest media.)
>
> --
> Liam Proven ~ Profile: https://about.me/liamproven
> Email: lpro...@cix.co.uk ~ gMail/gTalk/FB: lpro...@gmail.com
> Twitter/LinkedIn: lproven ~ Skype: liamproven
> UK: (+44) 7939-087884 ~ Czech [+ WhatsApp/Telegram/Signal]: (+420)
> 702-829-053
>

[cctalk] Re: Disk imaging n00b

[dwight via cctalk]

Disk compression gone wrong.
I had a number of files from a hard drive to save to floppies. Even compressed 
it took 3 floppies.
Al was fine until one night, I was carrying the box of these and other floppies.
As I got out of the car, I dropped several disc and before I could stop, my 
foot came down on the first disk, of the three ( in the dark).
I was never able to recover any useful information from any of the three disc. 
I didn't create those disc and the person that did had lost the source.
I am willing to waste space to keep the original format, of each file, as much 
as possible.
Any problem reading the first information of compressed files may mean the loss 
of all.
I only use compressed if it is to be re-expanded at it final destination.
Dwight

[cctalk] Re: Diablo series 30 or Dec RK03

[dwight via cctalk]

If all you want is a mass storage, you can do what I did for my NC4000 computer.
I took a controller board from an XT and a ST506 drive( only 5 Megs but how am 
I going to create
that much myself.
It is better than a floppy controller since it buffers a sector. The computer 
can run as slow or fast as it wants because you just send it the commands and 
wait until it tells you that the sector is ready. You can then just read it 
back, a byte at a time. There is no other special hardware to design, other 
than possible buffers to handle data size. The XT controller is simple enough 
to wire up to most any TTL level bus and all the tricky stuff is done for you.
My NC4000 was 16 bits and I needed to do byte operations. Since the processor 
could do short signed constants, I used the high memory address at 0 to do 
a byte swap, rather than do shifts but shifts would be fine, I just wanted to 
minimize the number of cycles.
I also did a floppy, that same way but the NC4000 was fast enough to read the 
status of the controller and transfer a byte at a time and keep up with the 
data rate of a 360 drive.
In fact I had to add some delay because it was too fast. I didn't do a DMA for 
it.
Dwight



From: Chris Zach via cctalk 
Sent: Sunday, January 8, 2023 4:06 PM
To: cctalk@classiccmp.org 
Cc: Chris Zach 
Subject: [cctalk] Re: Diablo series 30 or Dec RK03

> I think I've only ever seen pictures.  I know I haven't seen one up close.

There is "close" and there is "this thing is going to tip over on me"
close.

It was pretty impressive: Amazing lights panel that would allow you to
see what it was doing, what sector and track you were on, and all sorts
of stuff. I wrote a few quick programs to copy the lower 4k of memory to
a specific track, it was handy because I could then load up pretty much
any diagnostic tape image I wanted in a second.

Made a fair bit of noise spinning up, once running you could hear the
disks seeking, quite loud. The write protect panel had a square lighted
switch for each disk and a sector lockout that I think protected the top
sectors of the disk from writing.

One 6 foot rack would fit the panel, controller, one drive, and the
power supply for the drive then the controller. Pretty hefty, a second
drive was in the rack next to it above the pdp8/I and PC08 paper tape
reader. It was a truck. I wonder how it's doing these days...

C

[cctalk] Re: Typing class in high school

[dwight via cctalk]

I took typing in summer school before high school freshman. After 2 weeks I was 
at 20 WPM. At the end of the semester, I was at 20 WPM. 🙁
I have since resorted to index and thumb on both hands.
Dwight


From: Rick Bensene via cctalk 
Sent: Friday, January 27, 2023 11:41 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: Rick Bensene 
Subject: [cctalk] Re: Typing class in high school

>>
>> And, yes, even as a male I had typing in high school.
>>
>
> I had typing as an elective class in 7th grade in 1984. It gave me the
> ability to type in programs faster.
>

I took typing class in High School all four years.

Because I had developed an interest in typing when I was much younger, one of 
my relatives had given me an old Royal typewriter when I was something like 6 
years old.

I was proficient with the alphabet and had a pretty good vocabulary for my age, 
so I started to use the typewriter to write out my ideas for various inventions 
that I thought up(most of which were completely impossible, but I actually did 
make some of them).

Of course, I typed in a way that was  my own creation.   It was at first hunt 
and peck, and evolved as I got more familiar with the layout of the keyboard 
into my own version of touch typing.

I started using a Teletype 33ASR in sixth grade for learning programming on the 
HP 2000C timeshared BASIC system that the county school system owned, and the 
familiarity with a typewriter keyboard meant that I got pretty good at typing 
on the Teletype - being able to type on it about as fast as the mechanism would 
allow.

Since the vocabulary for typing in BASIC programs was fairly limited, my 
fingers got muscle memory on the various keywords and I could rip them out such 
that the interlock on the keyboard held back the pressure of the finger to type 
the next character in a keyword that when the mechanism finished printing, that 
key would immediately be depressed. About the only place I slowed down a little 
was typing literal text in PRINT statements, math expressions, and print 
formats in IMAGE statements.

By the time I got to the High School typing class, I could easily type 70-80 
WPM with very low error rates for extended periods of time, and could burst up 
to 110WPM.  But, I typed in a way that was completely incorrect as far as the 
formal way of typing goes.

After the first few weeks of class, it became apparent to the instructor that I 
could type quite well, as well as quite quickly, but I did it all wrong.   I 
was the second fastest typist in the class (there was a girl in the class who 
was faster), but I had the lowest error rate in sustained high-speed typing.

The teacher was a great guy.   He was constantly on me to type the right way 
out of due diligence, but didn't press it, and I'd constantly ignore him.

He would stand over me and watch me type, and would shake his head in both 
disgust, and in marvel that I could type as fast as I did using a completely 
bizarre method.  He often told me that it was a wonder that I didn't tie my 
fingers into knots typing the way that I did.

When it came time to grade my performance in the class, he was torn.  He told 
me that he wanted to give me a failing grade because I did not learn the proper 
way to type, but at the same time because I could type all of the material very 
accurately and quickly, he could not help but give me an A because I performed 
better than the vast majority of the students in the class despite the bizarre 
way that I typed.

I still use this strange way of typing to this day (many decades later), and 
can still type pretty darned fast, although my error rate has crept up quite a 
bit due to arthritis in my fingers, as well as general neurological degradation 
due to age.  It works for me, and in the end, I got all As in typing class for 
all four years.  I took the class after my Freshman year even though it was no 
longer required (it was required for all students to pass at least one year of 
typing in order to graduate, which was quite forward-thinking for those days) 
because I really liked the teacher, and the practice was good for keeping my 
speed up and error rate down, which proved very helpful for writing papers 
later on in High School, as well as in my computer programming classes and work 
after I graduated.

It's always interesting to study the unusual methods that get used when people 
(especially young people) come up with their own ways of doing things out of 
interest or necessity versus what is the traditionally-trained way.

I think in a lot of cases as people get into the school systems, their unique 
ways of doing things get trained out of them, even though their unique methods 
had evolved into a superior means of accomplishing something.

I had a great deal of respect for this typing teacher for realizing that my 
unique way of typing worked very well for me, didn't affect the results of what 
was required, and thus left 

[cctalk] Re: Multibus card haul

[dwight via cctalk]

I'm assuming that the 286/20 is a series II type with monitor built in?
If so, it has a single density floppy controller built into the IOC board.
You didn't post any pictures so I can't tell if there is a controller set 
there. Until I left Intel,
all the disk controllers were a two board set. One board was had the 3000 
series bit slice
chips and the other board had the analog board. When I was there, the double 
density,
M2FM boards sets were that way.
The series II keyboard was just a regular parallel, 8 bit keyboard. The earlier 
MDS 800 chassis
required a serial terminal. Most of these were made by BeeHive.
I left there when they were basically shutting down the development systems. 
They wanted
to move me to Rosedale, Ca.
Dwight


From: Chris via cctalk 
Sent: Saturday, January 28, 2023 6:02 AM
To: cctalk@classiccmp.org 
Cc: skogkatt...@yahoo.com 
Subject: [cctalk] Multibus card haul

I obtained a bunch of MB (1?) cards from a fellow list member. Mostly Intel, 1 
Matrox video card. Didn'y see a floppy controller anywhere, but I'll have to 
look closer. I have an Intel 286/20 chassis (the 20 doesn't mean mhz). Got to 
get me a keyboard and I'll be all set, right? O how I wish. There's an MDS 
keyboard on ebay, kind of pricey. Have to wonder where I'd stick the plug. No 
ribald suggestions please.

So apparently my future has taken a turn for the very grim. As I'll be writing 
device drivers from this point until my death. Yep. It's all rawhide and 
buffalo chips from here on out. Maybe sum yu westerners can give me a hand. 
Fred, Chuck, Sellam. You're all westerners and cowboys apparently. Just rustle 
up some docs and software for me.

[cctalk] Re: KIM-1 stuck bits from $280 to $29f

[dwight via cctalk]

It is unlikely that a 6 bits in a byte will fail, caused by a RAM, since each 
RAM chip is only one bit, not a byte.
It is more likely that one of the ROM chips is being doubly decoded. Since 
these are decoded as 1 K blocks, it is likely a problem with the address block 
decoder, the 74LS145.
Just my guess.
Dwight




From: Cameron Kaiser via cctalk 
Sent: Friday, May 12, 2023 8:51 AM
To: Jon Elson via cctalk 
Cc: Cameron Kaiser 
Subject: [cctalk] Re: KIM-1 stuck bits from $280 to $29f

> If the failure affects the EPROM monitor,then any results you get from the
> monitor are suspect.

No, what I mean is, the appearance of the upper six bits being dead was because
of how the monitor shifts in data from the keypad. Since bit 2 was always zero,
it would look like everything above it was zero too because the bit shifts
carried the error forward. A direct brute-force step through showed the actual
issue and I should have just done that in the first place. The monitor works
properly everywhere else outside of those locations, including from the TTY.

--
 personal: http://www.cameronkaiser.com/ --
  Cameron Kaiser * Floodgap Systems * www.floodgap.com 
* ckai...@floodgap.com
-- Ninety-nine percent of lawyers give the rest a bad name. ---

Re: Cross-talk square-wave?

[dwight via cctalk]

Is there any load resistance at the end of the line?

Dwight



From: cctalk  on behalf of Noel Chiappa via 
cctalk 
Sent: Wednesday, March 29, 2017 6:40:22 AM
To: cctalk@classiccmp.org
Cc: j...@mercury.lcs.mit.edu
Subject: Cross-talk square-wave?

Hi, a question about generic analog stuff.

In the process of getting SD cards to work, Dave is seeing square-wave noise
on a line. (1V of square wave, with pulses about 400ns long, running at
375kHz.) The line runs through a flat cable of modest length, along with
other signal-carrying lines. (No, we were not smart, and didn't put ground
lines between each pair of signal lines!)

Could cross-talk cause this kind of noise? We would have thought that you'd
only get spikes, associated with the rising and trailing edges of a signal in
a parallel wire, not a whole square-wave. During the constant-current period
in the middle of the pulse, there shouldn't be any cross-talk? Is there some
mechanism I/we don't understand that could do that?

(My guess is there's a leakage path in the circuitry on one end or the other,
not cross-talk in the cable, but...)

Thanks!

Noel

Re: Cross-talk square-wave?

[dwight via cctalk]

270K is not a transmission line load.

As I recall ribbon cable is around 100-150 ohms

impedance some place.

The signal does look nice and square.

I doubt is is inductive coupling, with that high a

load, I'd say it was capacitive.

inductive coupling requires current flowing.

Dwight



From: cctalk  on behalf of Al Kossow via cctalk 

Sent: Wednesday, March 29, 2017 2:35:54 PM
To: cctalk@classiccmp.org
Subject: Re: Cross-talk square-wave?



On 3/29/17 2:14 PM, David Bridgham via cctalk wrote:
> And I think this picture is the smoking gun.
>
> http://pdp10.froghouse.org/qsic/pic_24_2.gif
>
> Again, the bottom trace is the CS signal in question and the upper trace
> is now one of the QBUS DAL lines (after the bus transceiver and level
> converter) that's running across the ribbon cable near the CS signal.
> It does appear that induction can make a fairly clean square wave.
>
>

simple thing to try is split the ribbon cable between the two signals

Re: Cross-talk square-wave?

[dwight via cctalk]

again, I don't know the circuit, but I have personally witnessed this behavior 
on my PDP-8/e where a 7474 flip flop chip was bad. The input looked great and 
the output was "half baked"


I'll bet that flop was a Fairchild.

Dwight



From: cctalk  on behalf of W2HX via cctalk 

Sent: Wednesday, March 29, 2017 6:48:09 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: Cross-talk square-wave?

I am still not convinced it is coupling at all. You would expect the affected 
line to show a signal like dV/dt , no? I just don't think you can get square 
waves from square waves. That's not to say the input of some logic somewhere 
isn't getting triggered by unintended coupling and then getting "squared up" in 
some gate to produce the square we see.

Oh, and 270K surely is a transmission line load if the source has a 
characteristic impedance of 270K. Granted, that seems unusual and I don't know 
what the circuit looks like, but yes, most probably it is not a matched load. 
Having said that, given such a probable mismatch, then it is even harder to 
believe one could successfully couple a square wave onto such a transmission 
line unless the signal is actually being asserted on the line at a low 
impedance (ie the intentional output of a gate somewhere).

Looking at this picture
http://pdp10.froghouse.org/qsic/pic_24_1.gif

this shows exactly what I would expect to see with cross talk the little 
glitches on the CS line that correspond to edges on the clock signal. Classic 
dV/dt. scenario.

Looking at this one
http://pdp10.froghouse.org/qsic/pic_24_2.gif

again, I don't know the circuit, but I have personally witnessed this behavior 
on my PDP-8/e where a 7474 flip flop chip was bad. The input looked great and 
the output was "half baked"
Here is a screenshot of what I was seeing (look for "Line OUT E29 pin5" on the 
scope screenshot...)
http://w2hx.com/x/VintageComp/PDP-8e/M8650/LecroyScreen14.png
(post on that subject is here:  
http://www.vcfed.org/forum/showthread.php?55171-PDP-8-e-Project/page6 )

Anyhow, I dunno. My jury is still out on this one.

Eugene


-Original Message-----
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of dwight via 
cctalk
Sent: Wednesday, March 29, 2017 8:33 PM
To: Al Kossow; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Cross-talk square-wave?

270K is not a transmission line load.

As I recall ribbon cable is around 100-150 ohms

impedance some place.

The signal does look nice and square.

I doubt is is inductive coupling, with that high a

load, I'd say it was capacitive.

inductive coupling requires current flowing.

Dwight



From: cctalk  on behalf of Al Kossow via cctalk 

Sent: Wednesday, March 29, 2017 2:35:54 PM
To: cctalk@classiccmp.org
Subject: Re: Cross-talk square-wave?



On 3/29/17 2:14 PM, David Bridgham via cctalk wrote:
> And I think this picture is the smoking gun.
>
> http://pdp10.froghouse.org/qsic/pic_24_2.gif
>
> Again, the bottom trace is the CS signal in question and the upper
> trace is now one of the QBUS DAL lines (after the bus transceiver and
> level
> converter) that's running across the ribbon cable near the CS signal.
> It does appear that induction can make a fairly clean square wave.
>
>

simple thing to try is split the ribbon cable between the two signals

Re: Cross-talk square-wave?

[dwight via cctalk]

I didn't look clearly at the trace but it could also be

a reflected un-terminated line and not cross talk.

Dwight



From: cctalk  on behalf of Chuck Guzis via 
cctalk 
Sent: Thursday, March 30, 2017 1:59:00 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Cross-talk square-wave?

On 03/30/2017 01:21 PM, ben via cctalk wrote:

> Well that does not solve the ring, but off loading the SD card is a
> good idea, if you have the software time for a new cpu. Most of the
> time upper managment drags thier feet, unless they want it
> yesterday. Ben.

Well, Noel has stated that this will not be the situation in the final
stage, but my suggestion was done in the spirit of having a well-behaved
low-impedance linkup with the host; not something that resembles an antenna.

--Chuck

Re: RTX-2000 processor PC/AT add-in card (any takers?)

[dwight via cctalk]

I'd also like to have the board. I have a board with a NC4000 but never managed 
to get a RTX-2000.

One might say the NC4000 was the prototype for the RTX-2000.

The RTX-2000 could run applications several times faster than the same 
applications on a X86 machine of the time. They were often used as accelerators 
for different purposes. The ran two 16 bit busses at the same time and could 
execute as much as 4 operations in a single cycle.

Most instructions did a minimum of 2 operations in a single cycle.

Harris made the RTX-2000 in a rad hardened form so they were commonly used for 
satellites.

Having only a few gates for a processor meant they were more reliable for such 
applications

as well.

As an example. I wrote code for my NC4000, running at 2MHz that could sort 
1,000 integers in 19.1 ms, worst case.

I'm in silicon valley.

Dwight



From: cctalk  on behalf of Dave via cctalk 

Sent: Monday, April 10, 2017 11:41:34 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RTX-2000 processor PC/AT add-in card (any takers?)

I have a Harris RTX-2000 based system control board for a long defunct system.  
The board worked when removed more than 20 years ago in the mid 90's.  The 
RTX-2000 is a stack-based processor designed for running FORTH.  I think it was 
designed by Phil Koopman based on his graduate work.  The board is a 16-bit ISA 
board.  It was part of an MRI system that ran a version of MPE forth with a 
C-to-FORTH compiler (actually a C-like variant) that spits out a 16-bit FORTH 
variant with some embedded RTX-2000 code.

I also have another card with 3 channels of streaming 16-bit digital I/O, with 
special hardware to implement on-the-fly rotation matrices to the streaming 
output.
I have all the software and drivers as well. and I have written a c-based 
simulator that can run the FORTH/assembly emitted by the C-to-FORTH compiler 
(as well as the MRI libraries and hardware.)
If anyone wants to tinker with this hardware, or just pull the RTX-2000 chip, I 
would rather find a good home than toss the boards.
Dave

Re: If C is so evil why is it so successful?

[dwight via cctalk]

I know most don't get it but I like Forth because it is easy to follow the 
program flow and easy to test. C has too much boilerplate to solve the problem 
of not being able to use white space to keep things organized.

One uses Forth like a combination assembler and high level language. Most all 
the stack fiddle faddle is hidden at the lower assembly like levels. The high 
level code is like reading sentences. It always seems to me to be the most 
straight forward way to tell the computer what to do.

The order is left to right, top to bottom.

Testing can be done at any level, solving the complexity problem of proper 
testing.

I see too many programmers testing a program at the top level with something 
like 20 decision points to navigate through. When it seems to work, they call 
it tested. No wonder things are getting too complex to fix.

It isn't really the programming languages fault but most programming languages 
don't make it any easier.

Dwight



From: cctalk  on behalf of Eric Smith via cctalk 

Sent: Wednesday, April 12, 2017 2:33:38 PM
To: Sean Conner; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: If C is so evil why is it so successful?

On Wed, Apr 12, 2017 at 9:55 AM, Sean Conner via cctalk <
cctalk@classiccmp.org> wrote:

>   Yeah, I'm having a hard time with that too.  I mean, pedantically, it
> should be:
>
> #include 
> int main(void) { return EXIT_SUCCESS; }
>
> where EXIT_SUCCESS is 0 on every plaform except for some obscure system no
> one has heard of but managed to influence the C committee back in the late
> 80s.
>

Returning zero from main to indicate success is perfectly valid according
to the most recent three C standards.  ISO/IEC 9899:1990(E) §7.10.4.3,
ISO/IEC 9899:1999(E) §7.20.4.3 ¶5 and ISO/IEC 9899:2011(E) §7.22.4.4 ¶5
both requires that either 0 or EXIT_SUCCESS as an argument to exit() be
considered success.  EXIT_SUCCESS may or may not be zero, but zero is
considered success regardless of that.

One annoyance with the way the standard defines the EXIT_x macros is that
if you use other exit status values, including those from sysexits.h (not
part of the C standard), it's possible that an intended failure status
value might happen to match EXIT_SUCCESS on some standard-compliant
implementation.

§5.1.2.2.3 ¶1 of both :1999 and :2011 state that if execution reaches the
closing brace of main without a return statement, that it is equivalent to
returning zero, so even the return statement in this alleged non-portable
example is unnecessary.

On the other hand, the earlier ISO/IEC 9899:1990(E) §5.1.2.2.3 says that
main returning with no value yields an undefined termination status.

-- Eric "not a language lawyer but I play one on the internet" Smith

Re: APL and descendants - was Re: If C is so evil why is it so successful?

[dwight via cctalk]

To my knowledge, there is only one person that claims to

have a cartridge for the APL on the VideoBrain. He considers it

more valuable than gold and won't let anyone look at it or

dump its contents.

Such code running on a VideoBrain would surely warrant the /S

label for "Small".

Without some form of bank switching the resources of the VideoBrain

are minimal.

It has almost no RAM and the decoding has mirrored images through

the address space.

The F8 was clearly intended as an embedded controller similar to

the Rockwell PPS4.

Dwight




From: cctalk  on behalf of Eric Christopherson 
via cctalk 
Sent: Thursday, April 13, 2017 8:22:32 PM
To: Jecel Assumpcao Jr. via cctalk
Subject: Re: APL and descendants - was Re: If C is so evil why is it so 
successful?

On Thu, Apr 13, 2017, Jecel Assumpcao Jr. via cctalk wrote:
> Toby Thain via cctalk wrote on Thu, 13 Apr 2017 19:34:08 -0400
> > On 2017-04-13 6:54 PM, Chuck Guzis via cctalk wrote:
> > > So, whence APL today?
> >
> > Still lives on -- Dyalog, J, K, etc. Recently discovered the #jsoftware
> > channel on Freenode for APL fans.
>
> I consider Matlab and Julia to be spiritual descendents of APL.
>
> One thing that hurt APL in early microcomputers was that they used text
> mode with the wrong font. I would also have guessed that Basic could
> work better in really limited hardware, but some early APL
> implementations were impressively frugal.

The VideoBrain home computer had something called APL/S, but I can't
find any information on how it differs from APL. Does anyone know?

--
Eric Christopherson

Re: Pass on (Was: APL and descendants - was Re: If C is so evil why

[dwight via cctalk]

I have a tiny APL that was written for the 8080 someplace.

It has input that use ASCII keyboard input instead of the

funny characters.

I played with it a little on my IMSAI. The fellow had hand

written and assembled it by hand.

Not something I'd ever like to do.

I make to many simple mistakes and I don't have any interest

in erasure companies.

Dwight



From: cctalk  on behalf of jim stephens via 
cctalk 
Sent: Friday, April 14, 2017 8:49:38 PM
To: william degnan; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Pass on (Was: APL and descendants - was Re: If C is so evil why



On 4/14/2017 8:20 PM, william degnan via cctalk wrote:
> I've made a will, with a bunch of specific bequests.
No will, but at this point, the wife knows who to call.  Already trying
to figure out how to get things into longer term collections if they
will stay there, and not get ebay-ed immediately.  Hope it is far into
the future before that happens to any of us, but it happens.

Re: Extracting files off “unknown” 8 inch disks. Any thoughts…

[dwight via cctalk]

Hi Tez

 You where lucky. You had a format that was more or less standard. I have disk 
done in formats that are not so common.

One was a real toughie. I had some 5.25 and some 8 inch hard sectored disk in 
MFM format. These were for the Polymorphic machines. I'd modified a Polymorphic 
8 inch controller to run at the lower frequency of the 5.25 disk and was able 
to read most all of the 5.25 disk. This was the bulk of what needed to be done. 
I used my Poly88 as the reader and controlled it remotely from my PC through 
the serial lead.

I'd never got the time to reconfigure the controller board for the 8 inch disk. 
I finally got help form Chuck who was able to extract the data. Ihad to parse 
it into files but that was the easier part.

These are not in the common Polymorphic format that used the controller similar 
to the NorthStar. These were still hard sectored but MFM instead of FM. It was 
non-standard because it didn't use the ID and other MFM soft sectored markers.

What was cool about the 8 inch disk is that they contained the entire source 
code for the BASIC that Polymorphic used.

As an example of other formats, my Nicolet 1080 uses 8 inch 32 hard sectored 
disk and formats them as only two sector per track of 512 20 bit words.

None of these formats would read correctly on a PC controller.

One of the bit timing formats type of reader would have been needed.

Dwight



From: cctalk  on behalf of Terry Stewart via 
cctalk 
Sent: Monday, April 17, 2017 3:19:33 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Extracting files off “unknown” 8 inch disks. Any thoughts…

Hi,

Just an update on this.  I still haven't got those 8' floppies of unknown
origin to play with but I HAVE made a lot of progress with my own disks.
Thanks to everyone who gave me help with this.

Here's a writeup for those interested:
http://www.classic-computers.org.nz/blog/2017-04-15-adventures-with-an-8-inch-disk-drive-part1.htm
Adventures with an 8 inch (8”) disk drive - Part 1. New acquisition: A 
Mitsubishi 
M2896-63
www.classic-computers.org.nz
This page contains part 1 of an article on disk imaging experiences with an 8 
inch disk drive




Terry (Tez)

Re: Extracting files off “unknown” 8 inch disks. Any thoughts…

[dwight via cctalk]

Some times it reads part of the disk. I don't know what it is looking at but it 
won't format over some types of original data. I've often erased with supper 
magnet to get past such stuff.

It may also be that is just doesn't support 77 and can only do 80 tracks.

Dwight



From: cctalk  on behalf of Terry Stewart via 
cctalk 
Sent: Monday, April 17, 2017 4:36:01 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Extracting files off “unknown” 8 inch disks. Any thoughts…

>Here's a writeup for those interested:
>http://www.classic-computers.org.nz/blog/2017-04-15-
adventures-with-an-8-inch-disk-drive-part1.htm

One thing in this project puzzled me.   Initially when I was testing the
drive I tried to format it for 77-tracks. I used the command FORMAT B: /u
/T:77 /N:15  .   It wouldn't let me.  MS-DOS said "
"Formatting 1.15M
parameters not supported by the drive"

After trying a few other things (unsuccessfully)  I just tried a straight
FORMAT B: /u
It then formatted it without complaint?

Listening to the head moving, I counted 77 tracks. The last three tracks
the clicking stopped.  I'm assuming the head just wrote over that final
track 3 times.  MS-DOS told me I'd formatted for 1.2MB.

I'm puzzled why I couldn't format the disk using the /t:77 and /n:15
switches.  Did MS-DOS just go by what was in the CMOS.  If that's the case,
why have those switches at all?   Are they just legacy switches for
pre-CMOS machines?

Anyone know the answer to this?

Terry (Tez)

>
>

Re: What would cause a regular pattern of bad sectors?

[dwight via cctalk]

Heat damage can cause a fold or wrinkle as well.

Many format programs don't look at the index anymore as it isn't important for 
reading the disk. It is only used to indicate that the disk is turning.

That is why you see it moving each time you reformat. It is the same place on 
the disk surface.

Dwight



From: cctalk  on behalf of Paul Koning via 
cctalk 
Sent: Monday, April 24, 2017 6:16:26 AM
To: Terry Stewart; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: What would cause a regular pattern of bad sectors?


> On Apr 24, 2017, at 8:44 AM, Terry Stewart via cctalk  
> wrote:
>
> Hi guys,
>
> Ive been extracting data off a 3.5 inch windows XP-formatted floppy disk
> with many bad sectors.  The odd thing is it's always the same bad sectors
> on every track.  Such a 3, 8, 12 and 17.  Once or twice it might be just 3,
> 8 and 17.  Or occasionally 3, 8, 9 12, 17.  This patten is the same for
> every track.  It's  (more or less) always the same sectors that are bad.
> Why?  I can't believe natural degredation would be so consistent.  Anyone
> have any thoughts?

A radial scratch on the media?

paul

Re: Diablo 3x pictures

[dwight via cctalk]

I'll have to give mine a look. I hate that foam.

Dwight



From: cctalk  on behalf of Al Kossow via cctalk 

Sent: Friday, April 28, 2017 9:00:28 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Diablo 3x pictures

Was working on some Drives this week, and took some pictures of it disassembled.
http://bitsavers.trailing-edge.com/pdf/diablo/photos/Diablo_33F/

The prefilter was orange crumblefoam. I took a look at my NOS ones and they have
a greenish prefilter that still appears to be OK. The gasket going up to the 
plastic
basket that holds the pack is crublefoam as well. I'm going to try some 3/8" x 
1/2"
Norprene foam strip as a replacement, with polyurethane glue over the seam.

The door latch and load lamp is driving me nuts. Dug out my extender card this 
morning
to try and figure out why the driver transistors aren't turning on. Tranistors, 
diodes
are fine, and the J9 board that drives it works in another drive.

Re: Oscilloscope Recommendation

[dwight via cctalk]

If it is your only scope I recommend an analog scope of at least 100 MHz, with 
dual trace and delayed sweep.

If you already have an analog scope, I recommend a logic analyzer instead of a 
digital scope.

If you already have both above, I recommend a digital scope.

Dwight



From: cctech  on behalf of Michael Thompson via 
cctech 
Sent: Saturday, April 29, 2017 4:15:33 PM
To: allison
Cc: General Discussion: On-Topic Posts
Subject: Re: Oscilloscope Recommendation

Thanks for the recommendation

Sent from my iPhone

> On Apr 29, 2017, at 4:30 PM, allison  wrote:
>
>> On 04/29/2017 01:28 PM, Michael Thompson via cctech wrote:
>> The RICM just received $1,000 to buy a new oscilloscope. I would like a
>> four channel. and color would also be nice. The bandwidth doesn't need to
>> be high because we usually work on ancient equipment.
>>
>> What would you suggest?
>>
> I use a RIgol DSO at work to replace a 200mhz Tek with power issues.  Far 
> better scope.
> For the money we paid, 4 channels and wide band its very decent.  Being able 
> to get
> screen grabs to a USB stick is a big plus.
>
> I personally have a Rigol DS815T spec analyser with tracking generator and 
> its a good performer.
> Not up to the standards of a R&S FSH6 but about 1/15th the price.
>
>
> Allison

Re: IBM 4331 Mainframe

[dwight via cctalk]

Aren't these water cooled?

I seem to remember hoses.

Dwight



From: cctalk  on behalf of Dave Wade G4UGM via 
cctalk 
Sent: Monday, May 1, 2017 9:48:52 AM
To: 'Guy Sotomayor Jr'; 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: IBM 4331 Mainframe

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Guy
> Sotomayor Jr via cctalk
> Sent: 01 May 2017 05:39
> To: General Discussion: On-Topic and Off-Topic Posts
> 
> Subject: IBM 4331 Mainframe
>
> Just to let folks know that I finally moved the IBM 4331 Mainframe this past
> weekend from where it was currently stored to my shop.  Pictures are here:
> https://www.flickr.com/gp/150223282@N04/NrX91K
> 
>
> As can be seen in the pictures, it filled a 26’ box truck that I had rented 
> for
> this purpose.
> Right now I just have it placed somewhat in my shop.  Some early tasks will
> be:
>* I have to verify that I have everything.  Even if I missed some items, 
> they
> won’t be
>  scrapped.  I just need to go over what is currently in my shop and verify
> that I didn’t
>  leave anything behind.  I’m mostly worried about cables at this point.
>   * I have to figure out some way to produce enough “clean” 3-phase power
> to run the
> peripherals (the CPU is 220v single phase) as I only have 220v single 
> phase
> coming
> into my shop.
>
> Starting to power it up will probably be a while yet.  ;-)
>

Yes I remember having a gentle discussion with the University of Salford 
electricians, who wanted to know why I wanted 2 x 100amp feeds for the room 
into which the 4361 (I think it was a 4361, might have been a 4331 or 4341) was 
placed. I don't think we ever loaded them at 100amps but that was what IBM 
required. One was for the AirCon and the other for the CPU. If I remember 
properly those disks are the truculent ones. Assuming you have AirCon they need 
to sit for several hours to acclimatise.


> TTFN - Guy

Dave

Re: AB "Multibus"?

[dwight via cctalk]

Why do you ask?

Dwight


From: cctalk  on behalf of Ken Seefried via 
cctalk 
Sent: Tuesday, May 2, 2017 8:28:59 PM
To: cctalk@classiccmp.org
Subject: AB "Multibus"?

Are Allen-Bradley Multibus-1 form factor cards actually Multibus
compliant or something proprietary?

KJ

Re: 110 Baud modem

[dwight via cctalk]

Rtty was fsk. You needed a scope or a needle to

indicate when the BFO was centered.

That would be tuning.

I think the Wiky was talking about the 101 standard, not

the hardware.

One wonders what all the terminal strips were for.

Maybe more phone line or you could connect to more

TTYs

Dwight



From: cctalk  on behalf of Paul Koning via 
cctalk 
Sent: Tuesday, May 9, 2017 7:39:00 AM
To: Pete Lancashire
Cc: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: 110 Baud modem

So Wikipedia is wrong, since it claims that it was introduced in 1958 for ASCII 
and 110 Baud.

Then again, 101/103 modem modulation doesn't care about speed (it isn't 
clocked) up to a limit of 300 baud or so.

I wonder if there is also terminology here: what we now call a "modem" was 
earlier called a "tuning unit" and that term goes back to 5 bit machines and 
the 1950s.  It may be more a radio TTY term than a landline term, but the 
concept is identical.  I remember QST articles around 1958 or so about RTTY 
tuning units, built out of tubes with a relay (differential relay?) thrown in 
for good measure.

paul

> On May 9, 2017, at 10:32 AM, Pete Lancashire  wrote:
>
> The C version came later with the introduction of ASCII ( 5 to 8 bits ) and 
> 110 baud. So it does not go back to the 50's.
>
> I do not know when the C version was released. The ASCII Teletype Model 35 
> was introduced in 1961.
>
> -pete
>
>
>
>
> On Tue, May 9, 2017 at 6:47 AM, Paul Koning  wrote:
>
> > On May 8, 2017, at 10:27 PM, Pete Lancashire via cctalk 
> >  wrote:
> >
> > Bell 101C
> >
> > https://goo.gl/photos/hrhAwvzMBLWWteXu6
> >
> > https://en.wikipedia.org/wiki/Bell_101
>
> Interesting.  Released in 1958 but that unit is stamped 10 years later.
>
> It would be nice to see photos of the circuit boards.  And I sure wonder what 
> those rows of large relays are for.
>
> paul
>
>
>
>

Re: HP Draftmaster RX pen plotter needs love

[dwight via cctalk]

I would guess the lower voltages are generated from

a switcher off the 85 or 42 volt lines.

First check with an ohm meter in those lines to look for

a dead short.

Dwight



From: cctalk  on behalf of Philipp Pap via 
cctalk 
Sent: Tuesday, May 9, 2017 6:26:43 AM
To: michael.new...@gmail.com; cctalk@classiccmp.org
Subject: Re: HP Draftmaster RX pen plotter needs love

Hi Michael,
dear board

 Did you solve your power supply problem?

My Draftmaster I did work for 1 hour, I did even manage to do a demo plot.
 Then it died, right before my eyes the display got brighter and brighter and 
now - nothing when powering on, except a humming sound.
 I think that I’m responsible for the dead, as the plotter stood in an attic 
for 20 years, meanwhile power was raised from 220 to 230v (+-10%)
in Europe.
I realized that the input power can be adjusted between 220 and 240v at the 
power inlet of the plotter (on the top
there is a small stage for a screwdriver, then the cover opens and the rotating 
think can be taken out)!!

 Anyhow, now I have 41 and 83 Volts at the 42 and 85V test points,
 but always 0 Volts at the +5,-12,+12,+15V test points.
 The fuses are good and the secondary transformer seems good as well.
 Right now I am waiting for an esr-meter to test the capacitors,
any clue would be extremely helpful for me!

 With nice greetings Philipp
PS: tinkering with this masterpiece of engineering is fun, but now my back 
hurts, but it is worth it

Re: Commercial AIM-65 Video Controller?

[dwight via cctalk]

I don't believe the AIM-65 normally does color??

Dwight



From: cctalk  on behalf of Kyle Owen via cctalk 

Sent: Thursday, May 18, 2017 10:08:32 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Commercial AIM-65 Video Controller?

Any idea what this thing is?

https://imgur.com/a/aNFiK

Didn't come up with much of anything with Motion Control, Inc.

I did plug it in, and it seemed to come alive. I tempted fate again and
plugged a composite video source into the input, and a monitor into the
output. One pot on top adjusts the vertical sync, apparently; other than
making the colors slightly weird, the video came through more or less the
same. The other two (marked Y and Z cal) seemed to change nothing. The
switch mounted behind the pots caused the LED display to change (as seen in
the pictures), though the switch mounted closer to the right side of the
unit seemed to make no difference.

When I get done moving, I'll dump the EPROMs and get more pictures,
especially if there's sufficient interest.

Thanks,

Kyle

I hadn't made the connection before

[dwight via cctalk]

I was looking at an old GI catalog and casually noting the CP1610 that was most 
of a PDP11 processor. I did some more web surfing and noticed that the 
Intellivision game machine used this chip. It just never dawned on me that they 
used this processor.

I see that one could even get a keyboard for these.

Dwight

Re: I hadn't made the connection before

[dwight via cctalk]

Such things were often done on loyalty to previous companies.

It is like the Video Brain used the F8 or that Olivetti used the Z8000 for the 
M20.

The Video Brain was because the designer had worked on the F8 at Fairchild.

The M20 was because Faggin was Italian and had connections to Olivetti.

Such things were not always done because they were better or cheaper.

Woz was rare in his way of thinking at the time. He was mostly looking for cheap

but having a rich set of addressing mode was surely a plus.

Dwight



From: cctalk  on behalf of Cameron Kaiser via 
cctalk 
Sent: Friday, June 2, 2017 9:37:13 AM
To: ccl...@sydex.com; cctalk@classiccmp.org
Subject: Re: I hadn't made the connection before

> I sold a bare CP1600 chip about a year ago to a collector.   "Odd" is an
> understatement. A 10-bit wide instruction word, with the upper 6 bits of
> the opcode unused.   Loading a 16-bit address took three words.
>
> Also, slow, very slow, with no I/O instructions.

But that was because it has memory-mapped I/O, no? On the other hand the
decles were weird and it has a lot of instructions that were removed.

Retrospectively a 6502 or a Z80 would have looked like a better choice in
this application, even considering this was supposed to be a higher-end
console.

--
 personal: http://www.cameronkaiser.com/ --
  Cameron Kaiser * Floodgap Systems * www.floodgap.com 
* ckai...@floodgap.com
-- Knowledge puffs up, but love builds up. -- 1 Corinthians 8:1 ---

Re: Serial keyboards

[dwight via cctalk]

If you look on the ebay for a dolch ethernet sniffer, you'll see

many with no keyboard.

Why would someone separate the keyboard from a box when it

is clipped onto it?

These are not just any keyboard. They have custom shaped cases

and connector specifically for that model dolch.

What would anyone want with those keyboards?

Dwight



From: cctalk  on behalf of Dave Wade via cctalk 

Sent: Tuesday, June 6, 2017 2:02:34 AM
To: 'Henry Bond'; 'General Discussion: On-Topic and Off-Topic Posts'; 'Al 
Kossow'
Subject: RE: Serial keyboards



> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Henry
> Bond via cctalk
> Sent: 06 June 2017 00:49
> To: Al Kossow ; General Discussion: On-Topic and Off-
> Topic Posts 
> Subject: Re: Serial keyboards
>
> Seems somewhat counterintuitive / or simply is it just business?

Just business. Its made worse by the fact that DEC keyboards were considered 
reliable, and cheap compared to the terminals and so often discarded, but the 
terminals kept s spares.
I believe that the later PS2 variety could also be used on a PC with emulation 
software. Good keyboards are rare...

> Am I just going to have to pay over the odds for a good condition one
> whether I like it or not?

"Over the odds" implies that its over the market value. The odds are that a 
good DEC terminal keyboard will go for "top dollar"..
... especially in the UK and as that was a UK link I assume you are in the UK...

>
> On 6 June 2017 00:30:17 BST, Al Kossow via cctalk 
> wrote:
> >
> >
> >On 6/5/17 3:12 PM, Henry Bond via cctalk wrote:
> >> the same price for the keyboard as the terminal is greedy.
> >
> >
> >Welcome to the world of the keyboard collector, who buys up keyboards
> >and leaves terminals and classic computers behind, rendering them
> >useless.
>
> -- H

Dave
G4UGM

Re: Recovered a .bas file from my old Mac Plus

[dwight via cctalk]

If you still have a MAC plus handy you can experiment

by making short programs and viewing them in hex.

You can build up a translation dictionary that way.

I've done that for other Basics in the past.

You show 16 bit values, be careful they are sometimes

byte swapped. The original encoding is most likely bytes

and not words in size.

Dwight



From: cctalk  on behalf of Michael Hunter via 
cctalk 
Sent: Tuesday, June 6, 2017 8:32:14 PM
To: cct...@classiccmp.org
Subject: Recovered a .bas file from my old Mac Plus

Hey folks,

I hope all is well. Curiosity got the better of me and I sent in an EMAC
external HDD I had for my old Mac Plus in for recovery. I'm happy to report
that the recovery was a success. Now I'm struggling to figure out how to
get at the old content :)

The biggest prize was finding piano.bas, which is a BASIC piano program I
wrote that (if I recall correctly) allows you to set how many notes to have
between octaves.

Anyway, the .bas file is not plaintext, but I can see strings in it.  Here
are the first few bytes:

: f900 1b00 3aaf e84f 6e65 2046 7275 636b  :..One Fruck
0010: 6564 2075 7020 7069 616e 6f00 000c 0061  ed up pianoa
0020: 3af8 823a 20f8 8300 001e 009a 2022 5374  :..: ... "St

I remember watching a documentary saying that source code used to be
encoded / compressed.

Anybody have any suggestions on how to decode it? Sorry if it's poor form
to put this in the body but here's the whole file:

begin 644 piano.bas
M^0`;`#JOZ$]N92!&`)H@
M(E-T87)T:6YG('!I=&-H("@T-#`I(CMA```;`)H@(DAA;&8@H1()<@&P``
M`'<``!(`8CIDZF'N$_`H8N\/#"D```L`^,`@9"P@$P``$P"4('/J$2#E(!P3
MB#JI(',```D`9>IE[!(``!$`F"!EZA0@ER`;9@``$0"8(&7J&""7(!L`
M``!F```1`)@@9>H9()<@&P```&<```D`8NIB[!,```L`ER`;8@``"P!F
M.F+J8NP2```+`)<@&P```&(``!<`9SH@F"!G).HB>2(@ER`;:```"P"7
M(!L```!A```*`&@Z(&+J$0``"P"7(!L```!B```+`'H<`;@```L`ER`;
(8@``
`
end

Also, again sorry if this is poor form, but I'm looking to find a good home
for the Mac Plus, if you know somebody in the Bay Area who's interested
please let me know.

Thanks!

Mike

PS I'm interested in other formats I'm seeing too (.ht, some extensionless
thing that might be MacPaint), any pointers are appreciated!

Re: rectangular sense core vs. diagonal

[dwight via cctalk]

This is more like DRAM. There are bit lines and word lines.

All the address decoding is done outside the array.

No X Y partial addresses.

Instead of having one plain for each bit, the bits are all in the single plane.

Dwight



From: cctalk  on behalf of Christian Corti via 
cctalk 
Sent: Thursday, June 8, 2017 1:08:19 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: rectangular sense core vs. diagonal

On Wed, 7 Jun 2017, Paul Koning wrote:
>> How is ECS constructed?   I fooled with a lot of it back in the day, but
>> never got a good look at the core planes.
>
> I'd love to know.  I never saw the insides of ECS.  There are some
> documents on Bitsavers but none that I have seen show the ECS memory
> subsystem itself, certainly not at the circuit level.

I got two ECS modules, I put pictures of them on my FB album. I've
also put them on our server right now, at
ftp://computermuseum.informatik.uni-stuttgart.de/cdc/ecs/

The core planes are *huge*, about 4000cm² !

Christian

Sparcbook 1

[dwight via cctalk]

Ok, this will be a tough one.

I've located a Sparcbook 1 technical manual. It has a lot of good

information in it with schematics for the electronic.

It seems to be missing schematics for the power supply in

it. This takes the single input and creates all the other

voltages, like +-12V and such.

Does anyone have the schematics for the supply?

Dwight

Re: Sparcbook 1

[dwight via cctalk]

https://labs.ono-sendai.com/docs/SPARCbook%201%20Technical%20Reference%20Manual.pdf


 site has the technical manual. Several sites have the users manual ( I do have 
that one ).

Dwight




From: cctalk  on behalf of jim stephens via 
cctalk 
Sent: Wednesday, June 14, 2017 5:12:21 PM
To: cctalk@classiccmp.org
Subject: Re: Sparcbook 1

I'd love to get what you have with the remaining schematics and
technical info.

I don't have any such documentation right now or where to find any online.
thanks
jim

On 6/14/2017 4:44 PM, dwight via cctalk wrote:
> Ok, this will be a tough one.
>
> I've located a Sparcbook 1 technical manual. It has a lot of good
>
> information in it with schematics for the electronic.
>
> It seems to be missing schematics for the power supply in
>
> it. This takes the single input and creates all the other
>
> voltages, like +-12V and such.
>
> Does anyone have the schematics for the supply?
>
> Dwight
>
>
>

Re: Unknown boards

[dwight via cctalk]

I like the Elgin clock module. I didn't know they made electronic time pieces.

I'd guess the board is a clock generator.

Dwight



From: cctech  on behalf of william degnan via 
cctech 
Sent: Friday, June 16, 2017 10:02:18 AM
To: Jon Elson; General Discussion: On-Topic Posts
Subject: Re: Unknown boards

I checked and they are no GE 4000 system boards.

On Fri, Jun 16, 2017 at 12:57 PM, Jon Elson via cctech <
cct...@classiccmp.org> wrote:

> On 06/16/2017 09:31 AM, David Gesswein via cctech wrote:
>
>> Can anyone identify these boards? Person I got them from can't
>> remember
>> anything about them.
>> http://www.pdp8online.com/ftp/misc/unknown_boards/
>>
>> Date codes of 1964. Size 4.5"x3.25". Looks like used card edge for
>> keying but has separate 23 pin connector for electrical connection.
>> No useful markings I can see. Has card ## on the back.
>>
>> Search by picture didn't find anything.
>>
>> Thanks
>>
>> They remind me of RCA bizmac boards, which are likely to be related to
> GE, as that computer division changed hands a number of times.
>
> The connectors are Elco Varilok.
>
> Jon
>

Re: Fairchild F8

[dwight via cctalk]

If you want to mess with a F8, get your hand on a VideoBrain.

There is a group that has a lot of information as well.

Dwight



From: cctalk  on behalf of Mark Linimon via 
cctalk 
Sent: Friday, June 16, 2017 7:07:03 PM
To: ste...@malikoff.com; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Fairchild F8

On Sat, Jun 17, 2017 at 11:54:55AM +1000, Steve Malikoff via cctalk wrote:
> So, I've just joined and put up a few docs this Saturday morning...
>  https://archive.org/details/@galasphere347

ooh, F8 stuff.  My pile of that is on my to-do list for this summer.

There may still be a chip in a box somewhere ...

mcl

Re: Unknown boards

[dwight via cctalk]

The board in the bottom center is 6 buffers or inverters.

The upper right is 4 flipflops. The upper right is some type

of decoder( maybe an address or something ).

The bottom right is a clock generator and the one on the

lower left looks to be a massive gate, nor or nands depending on the logic used.

Function is not the issue, what machine used it is the question.

Dwight





From: cctalk  on behalf of Dominique Carlier via 
cctalk 
Sent: Friday, June 16, 2017 10:38:11 AM
To: william degnan via cctech
Subject: Re: Unknown boards

This reminds me the 5 boards that were in the back of my Uniservo 10/14
and which were the terminators (to put on the last tape drive connected
to the main controller). Maybe these boards have a similar function?

On 16/06/2017 19:02, william degnan via cctech wrote:
> I checked and they are no GE 4000 system boards.
>
> On Fri, Jun 16, 2017 at 12:57 PM, Jon Elson via cctech <
> cct...@classiccmp.org> wrote:
>
>> On 06/16/2017 09:31 AM, David Gesswein via cctech wrote:
>>
>>>  Can anyone identify these boards? Person I got them from can't
>>> remember
>>> anything about them.
>>> http://www.pdp8online.com/ftp/misc/unknown_boards/
>>>
>>> Date codes of 1964. Size 4.5"x3.25". Looks like used card edge for
>>> keying but has separate 23 pin connector for electrical connection.
>>> No useful markings I can see. Has card ## on the back.
>>>
>>> Search by picture didn't find anything.
>>>
>>> Thanks
>>>
>>> They remind me of RCA bizmac boards, which are likely to be related to
>> GE, as that computer division changed hands a number of times.
>>
>> The connectors are Elco Varilok.
>>
>> Jon
>>

Re: Unknown boards

[dwight via cctalk]

oops. the 4 flops are upper left.

Dwight


From: dwight 
Sent: Friday, June 16, 2017 9:31:15 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Unknown boards


The board in the bottom center is 6 buffers or inverters.

The upper right is 4 flipflops. The upper right is some type

of decoder( maybe an address or something ).

The bottom right is a clock generator and the one on the

lower left looks to be a massive gate, nor or nands depending on the logic used.

Function is not the issue, what machine used it is the question.

Dwight





From: cctalk  on behalf of Dominique Carlier via 
cctalk 
Sent: Friday, June 16, 2017 10:38:11 AM
To: william degnan via cctech
Subject: Re: Unknown boards

This reminds me the 5 boards that were in the back of my Uniservo 10/14
and which were the terminators (to put on the last tape drive connected
to the main controller). Maybe these boards have a similar function?

On 16/06/2017 19:02, william degnan via cctech wrote:
> I checked and they are no GE 4000 system boards.
>
> On Fri, Jun 16, 2017 at 12:57 PM, Jon Elson via cctech <
> cct...@classiccmp.org> wrote:
>
>> On 06/16/2017 09:31 AM, David Gesswein via cctech wrote:
>>
>>>  Can anyone identify these boards? Person I got them from can't
>>> remember
>>> anything about them.
>>> http://www.pdp8online.com/ftp/misc/unknown_boards/
>>>
>>> Date codes of 1964. Size 4.5"x3.25". Looks like used card edge for
>>> keying but has separate 23 pin connector for electrical connection.
>>> No useful markings I can see. Has card ## on the back.
>>>
>>> Search by picture didn't find anything.
>>>
>>> Thanks
>>>
>>> They remind me of RCA bizmac boards, which are likely to be related to
>> GE, as that computer division changed hands a number of times.
>>
>> The connectors are Elco Varilok.
>>
>> Jon
>>

Re: Free HP 9836 in Santa Cruz, CA

[dwight via cctalk]

Sounds like Bob Rosenbloom.

Dwight



From: cctalk  on behalf of Connor Krukosky via 
cctalk 
Sent: Friday, June 23, 2017 5:55:53 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Free HP 9836 in Santa Cruz, CA

I am in no way affiliated and wish it wasn't on the other side of the
country so I could get it!

https://sfbay.craigslist.org/scz/sys/6188389886.html

"I have a single monochrome HP 9836 computer with two monitors and three
printers left.
All completely untested, but free!"


Hope someone can save these, it looks like they might be owned by a
collector as it is?
Last photo has TWO ASR33s in the corners of the photo!

-Connor K

Re: Depressing article

[dwight via cctalk]

This is often called "The Information Era".

I've always called it "The Information Lost Era".

You may quote me.

Why the NASA person said to immediately destroy the tapes, one can only guess.

Those tapes belonged to the people of the USA. They were not some single 
persons option to destroy. We as tax payer own that information.

Dwight



From: cctalk  on behalf of Eric Christopherson 
via cctalk 
Sent: Friday, July 14, 2017 1:03:01 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Depressing article

On Fri, Jul 14, 2017 at 3:02 PM, Eric Christopherson <
echristopher...@gmail.com> wrote:

> On Fri, Jul 14, 2017 at 9:25 AM, Al Kossow via cctalk <
> cctalk@classiccmp.org> wrote:
>
>>
>> https://arstechnica.co.uk/science/2017/07/nasa-computer-engi
>> neer-basement/
>>
>> of events that happened two years ago that had to be obtained through a
>> NASA FOIA request
>>
>
> Another depressing recent article: https://www.theatlantic.com/
> national/archive/2013/12/scientific-data-lost-forever/356422/
>

Whoops, not *recent* recent. (I only just encountered it.)


>
> --
> Eric Christopherson
>



--
Eric Christopherson

Re: Diehl Combitron

[dwight via cctalk]

Now, if someone would just send me a Combitron, I could figure how to make it 
play pong on a scope.

The delay lines are serial, it was clever to use it to hold a video image.

One wonders what it would do if it tried to execute it?

I don't even care if someone sends me a NCR Combitron. I'm not that particular.

Dwight



From: cctalk  on behalf of Rick Bensene via 
cctalk 
Sent: Wednesday, July 19, 2017 8:13:05 AM
To: Christian Corti; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Diehl Combitron

This is a truly wonderful accomplishment, as well as a great remembrance of a 
true genius in early electronic calculator design, not to mention computer 
design.

Stan Frankel isn't all that well known, but those that do know of him hold him 
in high regard. He was a master of minimizing circuitry yet still providing 
great functionality. He deserves more of a place in history than he has 
received, but fortunately, more and more recognition of his accomplishments are 
being acknowledged by historians as time goes on.

I will pass this posting on to his son, Allan, with whom I communicate with 
frequently. I am sure he will love this remembrance of his father.

Rick Bensene
The Old Calculator Museum
http://oldcalculatormuseum.com


From: Christian Corti via cctalk 
Sent: Jul 19, 2017 4:20 AM
To: cctalk@classiccmp.org
Subject: Diehl Combitron

Hi,
I want to share the latest result of a bachelor thesis in our museum. We
are now able to program and load arbitrary machine programs and run them
on the Combitron. As a proof-of-concept, the student wrote an hommage to
Stanley Frankel, the designer of the CPU, by writing a boot tape that in
the end, fills the M delay line with data that is displayed on a scope,
triggering to the beginning of a 110 bit word.

http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf1.jpg
http://computermuseum.informatik.uni-stuttgart.de/pics/combitron/sf2.jpg

Christian

Re: Removing Pitting and Rust From an Enclosure

[dwight via cctalk]

You can't remove pitting. You mean remove the dark oxide?

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Wednesday, July 19, 2017 12:52:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Removing Pitting and Rust From an Enclosure

The TURBOchannel extender I got has a bit of rust and quite a lot of dark
pitting on the steel surfaces. I am not sure what the finish is, whether it
is anodized or galvanized. In any case, does anyone have recommendations for
how to remove the unsightly pitting? Bear in mind that I am in the UK, so
brands available in the US may not be available here and it may be more
useful to know what the active ingredients are.



Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg



Thanks



Rob

Re: Diskette size

[dwight via cctalk]

I have a system that uses hard sectored disk( 8 inch 32 sectors ) but only used 
two sectors 16 sector holes long.

I understand that the Wang systems used hard sectored with the holes around the 
outside of the disk.

There is more than size that is strange.

Dwight



From: cctalk  on behalf of Chuck Guzis via 
cctalk 
Sent: Friday, July 21, 2017 1:16:54 PM
To: cctalk
Subject: Re: Diskette size

On 07/21/2017 12:19 PM, Paul Koning wrote:

> Interesting.  Another example, slightly later, is the audio unit of the PLATO 
> IV terminal (1974 or thereabouts).  It uses a rather large disk, perhaps 10 
> inches diameter, brown oxide, no grooves.  It's a random access device, with 
> 128 tracks.  Each track has 32 sectors; a given audio clip can be up to 127 
> sectors long (though I'm not sure what happens if it's more than 32 sectors 
> -- does it switch tracks?  Seems unlikely).

There was also a 1954 Timex Magnetic Disc recorder--there was also a UK
product of a similar date and time--Pye, but that used grooved discs.
The advantage of the Timex format was that you could fold the disc up
and mail it to someone:

http://ftldesign.com/Timex/index.htm
http://www.obsoletemedia.org/pye-magnetic-disc/

> The track seek is done with a binary encoded pneumatic cylinder
assembly, 7 cylinders -- low order stroke is one track pitch, next is 2
tracks, next is 4 tracks, etc. So the binary track number would select 7
air valves which would feed supplied "shop air" to one or the other side
of each piston, moving the read/write head to the correct track.

I remember the same system used on the Univac Fastrand II drum; a great
big dual sewer-pipe unit, complete with fluorescent-lit observation windows:

https://www.fourmilab.ch/documents/univac/fastrand.html

At the time, I was fascinated by the positioning system.  A later (late
1970s) system was proposed for 8" hard drives using a setup of
concentric cups.  The outfit, run by a friend was called "Ontrack" and
never came to fruition.  There's probably a patent on file somewhere.
---
>From Fred:

> Although Chuck mentioned Dysan putting on hub rings, Verbatim (who
> were selling more) didn't do so until later. Therefore, some had
> hub-ring; some didn't. Office workers might as well have been told,
> "put the ones with hub rings into the drive with the asterisk",
> since lack of hub-ring and lack of asterisk mean nothing. Note: One
> of the options for The Berkeley Microcomputer Flip-Jig (MY first
> retail product) was a jig on the side of it for aligning and
> installing hub-rings.

Yup--the Dysan guys showed up with a jig and a bunch of self-sticking
hub rings before they were standard on their floppies.  They helped.

One of the things that apparently complicated matters is that Shugart
had the patent on the expanding-cone hub clamp.  If you look at a
Micropolis drive of the same time, they used a cup-and-rigid tapered
cone arrangement, which wasn't nearly as effective.

Of course, by the time 1.2MB (high density) drives came out, the problem
had been resolved on production drives, so almost all 5.25" HD floppies
are sold without reinforcement rings.

-
Those hub-reinforcing rings could be a pain in the posterior.  I vividly
recall one of our customers yelling about one of our copying products
producing bad copies.  Since we verified after writing, this seemed
somewhat unlikely.  We had them check the spindle speed--it was right on
the money.

After a few suggestions yielding no fruit, we had them send us some samples.

Sure enough--you copied to the diskette and couldn't read the result
successfully.   I was going nuts.

So I grabbed the Kyread/Visomag/Magnasee (whatever it was called back
then) and my microscope to see what I could see.   It was right about
then that I noticed that the samples had *two* reinforcing rings
installed--one on top of the other and offset slightly.

This interfered with the clamping action of the drive hub to produce an
effect that the same disk could never be clamped in the same position
consistently.

The problem was solved by the customer trashing his stock of blanks.

--Chuck












>
> These terminals also had a back-protection setup for the plasma panels (the 
> "slide projector", actually more like a microfiche projector).  Same sort of 
> setup, but with X and Y both done by binary weighted sets of 4 air cylinders 
> each.
>
>paul
>
>


--
--Chuck
-

"The first thing we do, let's kill all the spammers."

Re: Replacing flat drive belts alternatives?

[dwight via cctalk]

I wouldn't expect the cogged belt to work well.

The teeth would still cause jumps.

Now, if you came up with a way to grind the teeth off.

That might work.

Dwight



From: cctech  on behalf of Craig Ruff via cctech 

Sent: Sunday, July 23, 2017 8:45:41 AM
To: cct...@classiccmp.org
Subject: Replacing flat drive belts alternatives?

I would like to have both the drives in my HP 9895A working. Since flat belts 
for old equipment are becoming nearly impossible to find, has anyone had 
success replacing a flat belt with a toothed?  Either by reversing the belt or 
by also replacing the pulleys?  Or by the installation of an idler pully to 
correct for belt stretch?

Re: scary warning about bubble memory loop mask, TI 763/765 maint manual

[dwight via cctalk]

I wonder if they can be reset by just removing the bias magnets.

The bias field is needed to maintain the domains in the material.

Of course, that might make them totally useless.

Dwight



From: cctalk  on behalf of Al Kossow via cctalk 

Sent: Sunday, August 6, 2017 6:00:15 AM
To: cctalk@classiccmp.org
Subject: Re: scary warning about bubble memory loop mask, TI 763/765 maint 
manual

the terminals pop up on eBay every so often. I picked up a couple in poor 
physical
condition as donor machines for the one clean one I've found

On 8/5/17 10:56 PM, Eric Smith via cctalk wrote:

> With Intel devices, there is a special "seed module" and procedure that can
> be used to recover bubble devices which have become corrupted. TI just says
> that such devices have to be replaced, which is pretty difficult these days.
>

Re: VCF?

[dwight via cctalk]

It's over now.

I came away with about 3 times as much stuff as I when with.

I've not seen any photos posted yet.

For those that do post photos I recommend adding

xiiw as a single word. It will make searches easier.

Dwight



From: cctalk  on behalf of Ed via cctalk 

Sent: Sunday, August 6, 2017 2:06:48 PM
To: ci...@xenosoft.com; cctalk@classiccmp.org
Subject: Re: VCF?

Ol'  Fred -  Best of  luck  with surgery
Prayers be  with you...

Ed#


In a message dated 8/6/2017 11:27:03 A.M. US Mountain Standard Time,
cctalk@classiccmp.org writes:

How is  VCF going?


I was going to take a dozen boxes of books, a couple of  computers, and
some miscellaneous.
My health got in the way.
I'm  getting prostate surgery (ANOTHER TURP) on Thursday,
I just don't feel up  to packing loading, or even driving an hour each
way.


--
Grumpy Ol' Fred   ci...@xenosoft.com

Re: This Is Such An Exciting Listing!

[dwight via cctalk]

And the bidding has gone wild!

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Friday, August 18, 2017 4:13:56 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: This Is Such An Exciting Listing!

http://www.ebay.co.uk/itm/182707649701

Re: This Is Such An Exciting Listing!

[dwight via cctalk]

These are notoriously bad. Most radio repairers replace them without even 
measuring them to see if they leak.

"black beauties"

Tinker Dwight



From: cctalk  on behalf of Jon Elson via cctalk 

Sent: Friday, August 18, 2017 8:59:26 PM
To: couryho...@aol.com; gene...@ezwind.net; Discussion@
Subject: Re: This Is Such An Exciting Listing!

On 08/18/2017 09:32 PM, Ed via cctalk wrote:
> I was  going to   do the make an offer  for   $1
> alas... no USA shipping it  says!
>
> Sorry, this item cannot be posted to United States.
> You  are unable to bid on or buy this item because:
>  *   The  seller has specified that this item cannot be sent to
> addresses in United  States
>
>
> Ed#
>
>
> In a message dated 8/18/2017 7:25:05 P.M. US Mountain Standard Time,
> cctalk@classiccmp.org writes:
>
> And the bidding has  gone wild!
>
>
My favorite was a pair of "Les Paul" capacitors for roughly
$75 USD each.  These were USED oil-paper capacitors that
looked like they came from the 1950's or 60's.  Black
tubular with color code stripes, and leads about 1/4" long.

Jon

Re: A little power circuit explanation please

[dwight via cctalk]

The regulator needs about 2.5 to 3 volts head room. The circuit is what is 
often called a boost circuit. If my calculations are right, it should produce 
about 15.5 to 16V on C10. This gives the regulator enough over voltage to work 
as a regulator. If the supply you have is not regulated it won't be able to be 
used directly.

TR2 and L1 transformer form an oscillator. When TR2 conducts, it causes a field 
to build up in L1. When TR2 turns off, the field in L1 tries to collapse. The 
voltage build up until the diode conducts charging C10. This is often called 
fly-back. Coils like to keep conducting at a constant rate. Since TR2 turns 
off, the coils voltage will continue to rise until it finds a path to send the 
current ( the diode ).

When the voltage gets high enough across the resistor divider, R16/R15, TR3 
turns off. This removes the bias needed to turn on TR2, shutting down the 
oscillation.

If the voltage on C10 drops to the point that TR3 conducts, the oscillation 
will start again, boosting the voltage on C10 again.

Dwight



From: cctalk  on behalf of Adrian Graham via 
cctalk 
Sent: Wednesday, August 23, 2017 12:33:44 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: A little power circuit explanation please


> On 23 Aug 2017, at 00:49, Rob Doyle via cctalk  wrote:
>
> It's a little switching power supply.  It steps up the 9V input voltage to 
> something a few volts greater than 12V to feed the 12V regulator.
>
> If your 12V is correct, it is probably working.
>

This is from 2 months ago but I was puzzling over the 12V circuit in this 
particular machine and also maybe suffering from a red herring since the PSU I 
was using is from a ZXSpectrum+2 which is an unregulated 12-14V lump so the 
coil was already being fed 12V.

A

> Rob.
>
> On 8/22/2017 4:30 PM, Adrian Graham via cctalk wrote:
>> Hi folks,
>> Failing Atari PSU aside I remembered a question I had ages ago but never 
>> posted about the power circuit of another 80s home micro, the Enterprise 64. 
>> This machine is powered by a 2A 9V unregulated PSU and internally there’s a 
>> pair of 7805s and a 78L12 to smooth things out.
>> There’s also a small transformer coil in there too (L1 on the following 
>> schematic) and I’m not entirely sure what it’s for. Here’s the schematic of 
>> the original circuit, any enlightenment gratefully received since I have an 
>> Enterprise 64 with a dead coil :)
>> http://www.binarydinosaurs.co.uk/ep64PowerRegulators.png

[http://www.binarydinosaurs.co.uk/ep64PowerRegulators.png]


>> Cheers!
>> —
>> Adrian/Witchy
>> Binary Dinosaurs - Celebrating Computing History from 1972 onwards
>

Re: PSU Input Rectifier Question

[dwight via cctalk]

They would have electrolyte in them. It is mildly corrosive as it is mostly a 
borate solution. You can drill a couple holes in the tops of the case and drain 
them.

Since you say you've unsoldered the bases, are they wire or snap in. If snap 
in, you must get the lead clear of any solder touching the edge of the hole 
before you can think of any prying.

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Tuesday, August 29, 2017 1:01:14 PM
To: 'Maciej W. Rozycki'; 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: PSU Input Rectifier Question



> -Original Message-
> From: Maciej W. Rozycki [mailto:ma...@linux-mips.org]
> Sent: 29 August 2017 01:06
> To: r...@jarratt.me.uk; Rob Jarratt ; General
> Discussion: On-Topic and Off-Topic Posts 
> Cc: 'Tapley, Mark' 
> Subject: RE: PSU Input Rectifier Question
>
> On Tue, 29 Aug 2017, Rob Jarratt via cctalk wrote:
>
> > Not really no. The base of the capacitors is actually touching the
> > board, so I can't get under it to cut anything anyway, which is why I
> > am thinking I would have to cut the tops off them. Even if I could cut
> > one of the leads, I can't solder a capacitor underneath as that is
> > where the board is mounted into the enclosure, there is only room for
> > the mounting standoffs on the underside.
>
>  If you need to replace the caps anyway, then I think just cutting through
the
> outer PET sleeve should do as chances are it's only the sleeve that's got
glued
> and not the leads or the closing cap.  Then you might be able to just pull
the
> inner aluminium can containing the capacitor itself from the sleeve and
with
> the component proper out of the way get rid of any remains from the PCB.
>

Thanks Maciej,

I would just like to make doubly sure, before cutting into the outer body of
the caps, am I likely to hit any gotchas? Just how wet are they inside, do I
need to take any precautions with the electrolyte?


>  NB the originals are just snap-in capacitors AFAIK, e.g. Chemi-Con KMH
series
> (I can't figure that out from your photos and luckily none of my H7878s
has
> failed so far, so I haven't made this a part list for this PSU for
myself), still
> manufactured, so modern replacements should do.  With the PCB hole
> diameter supposed to be 2mm by the manufacturer's spec I wouldn't be
> bothered with a small lead pitch variation, you can always bend the leads
> slightly as there's some space between the closing cap and the rim that
rests
> against the PCB.
>


I did wonder if there would be enough tolerance. I have never encountered
these snap-in ones before, I don't know what they are like. Sounds like I
can try some snap-ins, which widens the choice immeasurably.


>  Also I would't be bothered about the LED holder getting damaged; it's a
> standard piece, available online.  I can dig out the part numbers,
separate for
> individual pieces of the holder (you can match different kinds against
each
> other, depending on your needs), if that would help; I ordered a bunch a
while
> ago for my own use.
>

I found some LED holders/clips which do seem to fit the bill, although I am
not sure I see how you get the old LED out, unless you have to break the
thing.

Regards

Rob

Re: Odd Ebay auction showed up today...

[dwight via cctalk]

Mostly a bunch of picked over junk.

Enough said.

Dwight



From: cctalk  on behalf of Dennis Boone via 
cctalk 
Sent: Monday, September 4, 2017 6:07:10 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Odd Ebay auction showed up today...

> Yeah, you usually are better off not sending messages. Inexplicably,
 > I once got a good deal out of him on an Altair 8800B Turnkey
 > system. It arrived very poorly packed, which was actually surprising,
 > given the price and his feedback (he does indeed move items, I've
 > ended up with a few messes he's sold people on my workbench).

He's known for crappy packaging, as well as the astronomical and ever
rising pricing.

De

Re: Odd Ebay auction showed up today...

[dwight via cctalk]

Hi Eric

 It is vintage-computer-store

Dwight



From: cctalk  on behalf of Eric Christopherson 
via cctalk 
Sent: Tuesday, September 5, 2017 8:58:16 AM
To: Robert; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Odd Ebay auction showed up today...

On Mon, Sep 4, 2017 at 1:47 PM, Robert via cctalk 
wrote:

> On Mon, Sep 4, 2017 at 12:07 PM, william degnan via cctalk
>  wrote:
> > I noticed that he had not been selling as much lately, I guess he ran out
> > of the good stuff and needs to close out the business, or raise new
> funds.
> > His normal list of Altairs and such appear to have all been sold.
>
> As best we can tell, he's moved all the good stuff to a new account,
> vintagecomputerstore, operating out of a location that's nearby but
> not the same. This must be the stuff that wasn't worth hauling to the
> new warehouse.


FWIW, vintagecomputerstore doesn't seem to exist on eBay.

--
Eric Christopherson

Re: Odd Ebay auction showed up today...

[dwight via cctalk]

The seller is in business. Old computers seem to be the target. They do not 
seem to have much computer knowledge. They seem to be a member of VCF and such 
as a business would be that sells such items. anyone can be a member They 
periodically change their seller name. They don't seem to be interested in 
having people correct their descriptions of items(personal experience).

I what their ebay sales with curiosity now. They do sell some items every now 
and then. I suspect it is enough to justify their efforts.

I've not found anything that they sell to be at a reasonable pricing but that 
is just my personal opinion.

Dwight




From: cctalk  on behalf of Sam O'nella via 
cctalk 
Sent: Tuesday, September 5, 2017 7:24:41 PM
To: Warner Losh; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Odd Ebay auction showed up today...

Since it wasn't said already, i think (if its the same user) they've posted 
similar auctions several times in the past also (over several years). You can 
see some of us discuss it in vcfed.org forums.
No affiliation or bad blood myself. I know i bought my working Columbia Data 
Products luggable from them years back. But i know they have premium/eBay 
prices generally.
We also occasionally see the reminder that the user is a member of the 
community and on some forums so despite opinion its a bit ashame to see bad 
mouthing of any collector. Albeit actual sales, and comments from first hand 
deals are certainly legitimate information.
null

Re: Strange grounding problem

[dwight via cctalk]

Were does the powerup signal go?

Dwight



From: cctalk  on behalf of Adrian Graham via 
cctalk 
Sent: Wednesday, September 27, 2017 5:23:45 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Strange grounding problem

Hi folks,

This is another Grundy Newbrain problem on a different machine that is probably 
easily explained by someone who understands current flow. This machine has two 
startup circuits that are simply a resistor and 10uF capacitor each, both 
feeding a Hex Schmitt Trigger (CD401068CM). When the caps have charged up 
sufficiently they activate both PWRUP and RESET signals one after the other 
thanks to the 220K and 560K resistors.

Schematic for the circuits is here - 
http://www.binarydinosaurs.co.uk/newbrainPowerupCircuits.png 
 - top circuit is 
PWRUP and the bottom one is RESET that goes straight to the Z80.

Only in this machine it doesn’t unless I have 3 sampling probes and a GND probe 
on my USB-powered logic analyser attached to pins 3-5 of the CD401068CM and the 
GND pin of any nearby chip. Less than 3 sampling probes and it won’t start so 
those probes must be facilitating current flow to GND?

Cheers!

PS Brent, I got the other Newbrain going by replacing the 74LS166 shift 
register, the one that provides the SOVSR signal. All good now!

—
Adrian/Witchy
Binary Dinosaurs - Celebrating Computing History from 1972 onwards

Re: OT: the death of shortwave / Re: Hallicrafters S-85

[dwight via cctalk]

One wonder how many SW hams were active in the Caribbean. Most hams today seem 
to be into 2 meter and not so much long range SW.

I would suspect it was still quite important.

As a fun project, a number of years ago, I used a modem card with a DSP chip to 
decode radio weather fax. I used to DSP to be a narrow band filter and to 
digitize the signal, when connected to a receiver. As far as I know, they still 
transmit weather fax on SW.

Dwight




From: cctalk  on behalf of Jon Elson via cctalk 

Sent: Saturday, October 7, 2017 7:51:14 PM
To: Brent Hilpert; gene...@ezwind.net; Discussion@
Subject: Re: OT: the death of shortwave / Re: Hallicrafters S-85

On 10/07/2017 06:46 PM, Brent Hilpert via cctalk wrote:
> SW is dead. The internet killed it. You can fix your S-40B
> but there won't be much to make it fly with. There are a
> couple international broadcasters left, but nothing like
> it used to be. I was an SWL'er as a kid in the 70s,
> learned a lot about the world. Voice of America, Armed
> Forces Network, Radio Japan, Radio Hilversum Holland,
> Deutsche Welle, HCJB Voice of the Andes, Radio Prague,
> Radio Moscow, Radio Peking, BBC, etc., etc., etc.
> Listening to the Cold War play out on the international
> airwaves. Pretty much all gone. Left between the static
> are a few religious broadcasters.
I used to do a lot of RTTY receiving.  I copied RCC in
Washington DC.  That was the Soviet embassy!  They'd send
some clear test stuff for a while, then go off the air for 5
minutes and start sending 5 digit code groups.

I also figured out how to decode a binary synchronous
transmission that turned out to be a police net among the
French-speaking Caribbean islands.  It was standard ITA2
(5-level teletype code, often called Baudot) with the start
and stop bits removed, and blocked into groups.

Only hams seem to use RTTY any more.  There are a plethora
of digital modes used by hams, though.

Jon

Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette subsystem : Restoration

[dwight via cctalk]

You can not fix anything without knowing what it is suppose to do. Chuck's idea 
is sound. You will not likely get much with the logic analyzer unless the 
processor is actually running some code.

It doesn't sound like it is. You need to check that it is.

Dwight




From: cctalk  on behalf of Dominique Carlier via 
cctalk 
Sent: Tuesday, October 17, 2017 10:50:29 AM
To: Chuck Guzis via cctalk
Subject: Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette 
subsystem : Restoration

Hi Chuck,

Yes I understand well. But the fact that the machines Z80 based were all
equipped with this famous serial I/O channel A and B, I therefore
thought that the principle of verification of these channels would
probably be the same on this type of architecture (Z80+PIO+CTC+SIO).
Therefore, there should be probably more people able to give me some
useful information.

Dominique


On 17/10/2017 19:26, Chuck Guzis via cctalk wrote:
> On 10/17/2017 04:56 AM, Dominique Carlier via cctalk wrote:
>> Hi guys!
>>
>> Nobody here has any information to help me to solve my problem?
>> Do you think I should talk about this breakdown on another forum? If
>> yes, have you an address to recommend me?
>>
> Dominique, the probably reason that many of us don't jump in is that
> you've got a tough job, given the house-numbered ICs and lack of visible
> traces.
>
> If this were my system and I was determined to get it working, I'd
> probably start by dumping and disassembling the ROMs to find out exactly
> what set of program steps occur to produce the error message.
>
> I'd probably then write a diagnostic ROM that would allow me to probe in
> detail to characterize the fault.  The happy circumstance is that the
> display (and possibly the keyboard) is functional.)
>
> Then I'd jump in with a logic analyzer or ICE to determine the exact
> nature of the failure and its source.
>
> You can see that this is an arduous process that few are equipped to
> help you diagnose remotely.
>
> My two cents' worth,
> Chuck
>
>

Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette subsystem : Restoration

[dwight via cctalk]

Since you know the pinout of the SIO chip, you might first look to see if where 
the rx and tx pins go. This may require some hunting with an ohm meter. I'd 
suspect they go to a RS232 level shifter.

You may also have to write some code to run the serial chip and any possible 
external loopback. As I recall these chips may have an internal loopback.

If you have a working logic analyzer, you can trigger on the select pin to the 
SIO and look to see what address the SIO is located at. That will allow you to 
create some debug code.

I'm not saying this is easy. Still, this is the way I'd attack the problem as a 
start.

You have to realize, there is not much more we can do for you.

Creating a ROM with a diagnostic looping program is about the only practical 
way to deal with a machine with no documentation.

I fixed an old mini once without schematics but it was all DTL and TTL and 
there were signal names at the card edges.

You have a Z80 computer. If you can program EPROMs you have a chance, otherwise 
it is unlikely that your current easter egg hunting method is likely to be very 
fruitful. You have already gone through most all of the likely failure items. 
From here you will likely have to begin to troubleshoot.

Dwight



From: cctalk  on behalf of Dominique Carlier via 
cctalk 
Sent: Tuesday, October 17, 2017 1:59:47 PM
To: Chuck Guzis; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette 
subsystem : Restoration

Thanks for your response Chuck,

As described in the topic, just after the Power On, the machine runs a
self-test which is called "POC TEST" on the UTS range of Sperry Univac.
During this test, the machine checks the status of the RAM, the ROMs,
the Counter Timer, and the various communication interfaces.
Everything is OK except the ninth line which says: "SERIAL I / O CHANNEL
B: FAILED"

(ignore the FAILED next to "OPTIONAL RAM BANK 0,1", the machine can
start without this board)
http://www.zeltrax.com/classiccmp_forum/uts40_screen03.jpg

This channel B error completely freezes the machine, it does not load
the default settings, I no longer have access to the setup page, in this
situation the keyboard remains without effects.

When the POC test is successful, it loads the default settings in non
volatile RAM:
http://www.zeltrax.com/classiccmp_forum/uts40_screen01.jpg

And I can access the setup page:
http://www.zeltrax.com/classiccmp_forum/uts40_screen02.jpg

The few times I was able to go into the setup page (CHANNEL B: PASSED),
I rushed to try to encode (with the dead keyboard) the data to declare
the subsystem and finally return to the CP/M mode. And I had twice the
case where without warning hop! Blank screen, automatic reset, self-test
(POC) -> SERIAL I / O CHANNEL B: FAILED (again).
Maybe we have there some interesting information about the problem, the
intermittent nature of this failure, could this give information about
the type of component in fault?

But note that since weeks now the problem has become permanent, I have
never been able to return to this famous setup page and the "serial I/O
channel B" is now always marked as 'FAILED'.

So I have no way to try anything using the terminal at this point.

It is possible that the breakdown is in fact very simple (dry solder dry
or attacked solder by the acid of the battery), but I would like to
avoiding to rework all the solders, and maybe to finally find that the
problem was at the level of an IC, I would try to locate the components
linked to this problem. I look at the SIO, try to discover what is after
just after, see how I can eventually act on the pin 30 (W/RDYB) of that IC :
http://www.sbprojects.net/projects/izabella/assets/images/sio1.jpg


And try to understand why this SIO no longer considers the channel B as
'READY'
This kind of things ...
There are probably programmable loop-back circuitry used by the POC test
program (in the ROM of the program cartridge).To ignore the negative
diagnostic I would like to induce to the self-test program that the
channel B is OK, what should I inject to the SIO (perhaps on this pin
30) to force a positive diagnosis?
It would be interesting, just to see if in that way I can take control
again on the machine, and check that the rest is working.

And yes, the SIO is working (as the CPU, the counter timer and the DMA
controller) because I replaced these IC by another ones with the same
faulty result.
http://www.zeltrax.com/classiccmp_forum/sio_issue_01.jpg

Thanks for your help ;-)

Dominique


On 17/10/2017 20:22, Chuck Guzis via cctalk wrote:
> On 10/17/2017 10:50 AM, Dominique Carlier via cctalk wrote:
>> Hi Chuck,
>>
>> Yes I understand well. But the fact that the machines Z80 based were all
>> equipped with this famous serial I/O channel A and B, I therefore
>> thought that the principle of verification of these channels would
>> probably be the same on this type of architecture (Z80+

Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette subsystem : Restoration

[dwight via cctalk]

By the way, how is the terminal and keyboard connected to the computer?

Is it by RS232?

If so, it might be through SIO B. If this is the case, it might be the problem.

Also, the RAM failure may be the issue as well. You have something that is 
intermittent there. Bad RAM can cause programs to misbehave as well. Just 
because it passes some times doesn't mean it is good enough to run programs.

Dwight



From: cctalk  on behalf of dwight via cctalk 

Sent: Tuesday, October 17, 2017 4:08:46 PM
To: Dominique Carlier; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette 
subsystem : Restoration

Since you know the pinout of the SIO chip, you might first look to see if where 
the rx and tx pins go. This may require some hunting with an ohm meter. I'd 
suspect they go to a RS232 level shifter.

You may also have to write some code to run the serial chip and any possible 
external loopback. As I recall these chips may have an internal loopback.

If you have a working logic analyzer, you can trigger on the select pin to the 
SIO and look to see what address the SIO is located at. That will allow you to 
create some debug code.

I'm not saying this is easy. Still, this is the way I'd attack the problem as a 
start.

You have to realize, there is not much more we can do for you.

Creating a ROM with a diagnostic looping program is about the only practical 
way to deal with a machine with no documentation.

I fixed an old mini once without schematics but it was all DTL and TTL and 
there were signal names at the card edges.

You have a Z80 computer. If you can program EPROMs you have a chance, otherwise 
it is unlikely that your current easter egg hunting method is likely to be very 
fruitful. You have already gone through most all of the likely failure items. 
From here you will likely have to begin to troubleshoot.

Dwight



From: cctalk  on behalf of Dominique Carlier via 
cctalk 
Sent: Tuesday, October 17, 2017 1:59:47 PM
To: Chuck Guzis; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: The SPERRY UNIVAC UTS 40 system + 8406 double-sided diskette 
subsystem : Restoration

Thanks for your response Chuck,

As described in the topic, just after the Power On, the machine runs a
self-test which is called "POC TEST" on the UTS range of Sperry Univac.
During this test, the machine checks the status of the RAM, the ROMs,
the Counter Timer, and the various communication interfaces.
Everything is OK except the ninth line which says: "SERIAL I / O CHANNEL
B: FAILED"

(ignore the FAILED next to "OPTIONAL RAM BANK 0,1", the machine can
start without this board)
http://www.zeltrax.com/classiccmp_forum/uts40_screen03.jpg

This channel B error completely freezes the machine, it does not load
the default settings, I no longer have access to the setup page, in this
situation the keyboard remains without effects.

When the POC test is successful, it loads the default settings in non
volatile RAM:
http://www.zeltrax.com/classiccmp_forum/uts40_screen01.jpg

And I can access the setup page:
http://www.zeltrax.com/classiccmp_forum/uts40_screen02.jpg

The few times I was able to go into the setup page (CHANNEL B: PASSED),
I rushed to try to encode (with the dead keyboard) the data to declare
the subsystem and finally return to the CP/M mode. And I had twice the
case where without warning hop! Blank screen, automatic reset, self-test
(POC) -> SERIAL I / O CHANNEL B: FAILED (again).
Maybe we have there some interesting information about the problem, the
intermittent nature of this failure, could this give information about
the type of component in fault?

But note that since weeks now the problem has become permanent, I have
never been able to return to this famous setup page and the "serial I/O
channel B" is now always marked as 'FAILED'.

So I have no way to try anything using the terminal at this point.

It is possible that the breakdown is in fact very simple (dry solder dry
or attacked solder by the acid of the battery), but I would like to
avoiding to rework all the solders, and maybe to finally find that the
problem was at the level of an IC, I would try to locate the components
linked to this problem. I look at the SIO, try to discover what is after
just after, see how I can eventually act on the pin 30 (W/RDYB) of that IC :
http://www.sbprojects.net/projects/izabella/assets/images/sio1.jpg


And try to understand why this SIO no longer considers the channel B as
'READY'
This kind of things ...
There are probably programmable loop-back circuitry used by the POC test
program (in the ROM of the program cartridge).To ignore the negative
diagnostic I would like to induce to the self-test program that the
channel B is OK, what should I inject to the SIO (perhaps on this pin
30) to force a positive diagnos

Re: Cleaning and Restoring a Badly Corroded PSU

[dwight via cctalk]

I don't see why you have assumed that one of the capacitors has leaked. The 
corrosion could have come from water or condensation onto the board.

I don't see any corrosion on the components.

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Monday, October 23, 2017 1:45:42 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Cleaning and Restoring a Badly Corroded PSU

I am now looking at the H7826 PSU that came with a TURBOchannel Extender. It
looks like there may have been capacitor leakage and some heatsinks will
need to be replaced. I have posted pictures here:



https://robs-old-computers.com/2017/10/23/corroded-h7826-power-supply/



So two questions:



1.   Any suggestion on how to clean the board? Some of the corners are a
bit inaccessible to reach with just a cotton bud and isopropyl.

2.   Do those heat sinks have a particular name/spec that I can search
for?



Thanks



Rob

Re: Cleaning and Restoring a Badly Corroded PSU

[dwight via cctalk]

I would remove the transformers before putting it in the wash.

The big one doesn't look to be hermetically sealed.

Dwight



From: cctalk  on behalf of Phil Blundell via 
cctalk 
Sent: Monday, October 23, 2017 3:27:29 PM
To: r...@jarratt.me.uk; Rob Jarratt; General Discussion: On-Topic and Off-Topic 
Posts
Subject: Re: Cleaning and Restoring a Badly Corroded PSU

On Mon, 2017-10-23 at 21:45 +0100, Rob Jarratt via cctalk wrote:
> I am now looking at the H7826 PSU that came with a TURBOchannel
> Extender. It
> looks like there may have been capacitor leakage and some heatsinks
> will
> need to be replaced. I have posted pictures here:
>
>
>
> https://robs-old-computers.com/2017/10/23/corroded-h7826-power-supply
> /

Maybe the photos don't do justice to the full horror but it doesn't
look all that bad from what you've posted.

The heatsinks do look a bit corroded but, if they are aluminium (which
I would guess they are from the photos) then this might just be
dampness rather than anything more sinister.  Aluminium does tend to
rot a bit in prolonged contact with water, and if it is also in contact
with steel then you get an electrolytic reaction which can be fairly
ruinous.

I doubt the heatsinks are a standard part you can buy off the shelf.
They have a bit of a custom look about them.  But, unless you are
worried about authenticity of those parts, a standard heatsink from
Farnell etc will work just fine.  If you do want the authentic article
then you might need to get some replacements machined.

As for cleaning the board, given that it seems to be relatively low-
tech I would probably be fairly comfortable putting it in the
dishwasher on a shortish cycle.  Then give it a bit of a rinse with
deionised water and let it dry out.

The caps don't look obviously leaky, and (unlike batteries) it doesn't
seem to be common for capacitors to ooze their electrolyte without
fairly evident physical distress.  But replacing them is probably a
good plan anyway!

p.

Re: HP 21mx/whatever processor works with doublesided key... i forgot model#

[dwight via cctalk]

Most real lock smiths can make a key for it. Just remove the lock and bring it 
to them.

Dwight



From: cctalk  on behalf of Ed via cctalk 

Sent: Friday, October 20, 2017 8:24:28 PM
To: jw...@classiccmp.org; cctalk@classiccmp.org
Subject: Re: HP 21mx/whatever processor works with doublesided key... i forgot 
model#

IT RUNS MEMORY RESIDENT  LOADED  FROM PAPER TAPE?
ED#


In a message dated 10/20/2017 7:37:48 A.M. US Mountain Standard Time,
jw...@classiccmp.org writes:

"Forth-like" system that is well developed/flushedout. So in  addition to
BASIC, you get oh-so-many-wonderful-things. I very highly  recommend that
anyone messing with 21mx/1000 systems take a good look at  HP-IPL/OS.

Re: NEC 4164-12

[dwight via cctalk]

One caution for 4164s. When they first came out, there were some that were 256 
cycle refresh and others that were 128 cycle.

There is no way by looking at them to tell which is which other than getting a 
matching original manufacture document.

Many machines expect 128 cycle. You can use 256 cycle on chips designed for 128 
but not the other way around.

Most Z80 setups only do 128 unless it has additional hardware to handle the 
extra bit ( not to likely ).

Dwight



From: cctalk  on behalf of Ethan Dicks via 
cctalk 
Sent: Saturday, October 28, 2017 1:31:36 PM
To: e. stiebler; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: NEC 4164-12

Hi, Emanuel,

I have a quantity of 4164 DRAM from the Comboard days, new in tube.  It is
likely to mostly be 150ns and I don't know the brands until I dig it out,
but I will check when I get home.  If it matches what you need, I'm happy
to send some to you.

-ethan

On Oct 28, 2017 12:32, "emanuel stiebler via cctalk" 
wrote:

Hi all,
anybody has some spare in the bin, he doesn't need?

Looking for 18 pieces, preferably NEC, -12.

Thanks!

Re: NEC 4164-12

[dwight via cctalk]

Nice chart Chuck.

Dwight



From: cctalk  on behalf of Chuck Guzis via 
cctalk 
Sent: Saturday, October 28, 2017 10:19:53 PM
To: dwight via cctalk
Subject: Re: NEC 4164-12

On 10/28/2017 10:14 PM, dwight via cctalk wrote:
> One caution for 4164s. When they first came out, there were some that were 
> 256 cycle refresh and others that were 128 cycle.
>
> There is no way by looking at them to tell which is which other than getting 
> a matching original manufacture document.
>
> Many machines expect 128 cycle. You can use 256 cycle on chips designed for 
> 128 but not the other way around.
>
> Most Z80 setups only do 128 unless it has additional hardware to handle the 
> extra bit ( not to likely ).
>

There's a great chart of the 4164s and their characteristics here:

http://www.minuszerodegrees.net/memory/4164.htm

NEC 4164 use 128 cycle refresh, but so do many others.

--Chuck

An interesting read

[dwight via cctalk]

Look at Dr Dobb's August 1979. There is an article on computer crime. It is 
interesting how times have changed.

Dwight

Re: Computing Pioneer Dies

[dwight via cctalk]

It was interesting, going looking at some of the youtube videos from some of 
the inventors.

It seems that the only reason it didn't have a machine writable program memory 
was cost.

It had the ability to do conditional flow and used an instruction decoder.

Previous computers were patched pieces like counters, adders, inverters and 
constants. Flow control was done with counters and data was passed to the next 
patch.

RAM was just becoming available with things like the William's tube. Otherwise 
RAM was a number of flipflops made with vacuum tubes. At two triodes per latch 
the cost per bit was quite high. A diode ROM array made sense.

The concept was there, only the implementation was different.

I was like that two with the thought of how the program was loaded but when one 
considers the leap from a number of patched elements to a cpu, the ability to 
have RAM loadable wasn't as relevant until until they got away from the 
Manchester architecture.

Dwight


Dwight


From: cctalk  on behalf of Paul Birkel via 
cctalk 
Sent: Monday, November 13, 2017 11:52:15 PM
To: 'Noel Chiappa'; 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Computing Pioneer Dies

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel
Chiappa via cctalk
Sent: Monday, November 13, 2017 5:00 PM
To: cctalk@classiccmp.org
Cc: j...@mercury.lcs.mit.edu
Subject: Re: Computing Pioneer Dies

> From: Brent Hilpert

> What about that little issue of writeable program storage?

Just to clarify my understanding of your position, is a system with a CPU
chip (say one of the 68K models) with only ROM not a 'stored program
machine'?

Noel

PS: You really should look at the book ("ENIAC In Action"), and not rely on
the articles; it's later, more coherent (not being split across a handful of
papers), and much more detailed (e.g. it includes the instruction set for
the
'programmed' version of the ENIAC).

-

Note that most of the BRL references in the three articles in the IEEE
Annals of the History of Computing are available online through DTIC.
Search using Google Scholar.

Unfortunately the referenced manuscripts located in private archives appear
to remain inaccessible to the general public.

Tables I thru III in the second paper, offering a set of side-by-side
comparisons for "ENIAC, EDVAC, and three other computers of the late 1940s"
are well worth contemplation.  The third paper puts a practical perspective
on the somewhat more theoretical perspectives of the first two papers. "1948
ENIAC" was a quite interesting reorganization/application of the computing
resources available in the "1945 ENIAC".

It looks like the somewhat less expensive paperback for "ENIAC in Action" is
due for publication in January.

Noel:  Does the book make any attempt to trace any technological/social
effects *from* the "1948 ENIAC" to other computer developments?  Or are we
to conclude that the "1948 ENIAC" was aa significant "existence proof" for
aspects of the First Report (and evidently quite productive as a
computational tool) but sterile with respect to direct progenitors and
impact on other computer developments of the late-1940's?  For example, do
they cite any evidence that either BINAC or early UNIVAC were other than
"from whole cloth" in nature?  Any of the "IACs"?  Perhaps more at the level
of "coding style/procedures" than hardware
architecture/design/implementation?

As an engineer, I like systems that "get stuff done" and the "1948 ENIAC"
certainly qualifies.

As a (computer) scientist I like what SSEM demonstrated and the fact that it
had direct (physical & intellectual) offspring.

As a practical person I like that the SSEM directly led to the "first
general-purpose commercially produced computer" (Ferranti Mark 1).

There's a lot to like in the span of 1945-1955!

-
paul

Re: Need help with an odd design construct

[dwight via cctalk]

Why not just measure the voltage across the resistor. That will tell you the 
amount of current flowing.

Dwight



From: cctalk  on behalf of Brent Hilpert via 
cctalk 
Sent: Tuesday, November 14, 2017 6:29:47 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Need help with an odd design construct


On 2017-Nov-14, at 4:51 PM, Jim Brain via cctalk wrote:

> On 11/14/2017 6:32 PM, Brent Hilpert via cctalk wrote:
>>
>> Once the cart is pulled the 4008 chip should end up in standby mode - no 
>> enables asserted.
> The 3K3 ties both !CROM and !CRAM high, and they are both open collector 
> outputs on the port.
>
> But, I forgot to put one important detail in the original note.  I so 
> apologize.  The original cart has a HM62256LP-12, but it is evident from the 
> traces being cut on the cart that this was not even the original SRAM.  I do 
> believe the original SRAM was 32kB in size, though.
>
> SInce the original SRAM was not even original, I replaced with the '4008 for 
> various reasons.
>>
>> In standby a CMOS chip like this will appear as a near infinite impedance, 
>> so there isn't much voltage dividing going on with a 6.8K R.
>> The full battery voltage (minus epsilon) will be across the chip.
> Then, why do the 6K8 there?
>>
>> The datasheet specs standby current Isb1 at typically 4 uA (50 max).
>> Ohm's law will get you an idea of the effective resistance of the chip if 
>> you really want to calculate what epsilon is here.
> I'll try and calculate it for the HM62256LP, which seems to be .5mA under no 
> load:
>
> http://www.farnell.com/datasheets/97905.pdf
>
> (2.7/.0005) = 5K4?That seems incomplete, like I need to also take into 
> account that .5mA flows through the 6800 resistor, but that means 
> (6800*.0005) = 3.4V, which can't be right.
>
> If I put that into a Voltage Divider (2.7V Vih, R1 = 5400, R2 = 6800, output 
> is 1.5V, implying the GND line is at 1.5V relative to the battery...
>>
>>
>> Why the circuit might be as you have it with the 6.8K I'm not sure, perhaps 
>> for some current limiting or glitch suppression as the cart is pulled out/in.
>> Doesn't really matter much as the only other thing on that gnd side is the 
>> switches.
> And they aren't there on the original.
>>
>> Those 4 10K resistors are kind of weird, each 'on' switch is chewing up 
>> orders of magnitude more battery current than the chip,
> Good point.  I copied the design from the "ROM cart" schematic, where the 
> battery is not in place, and the switches were there to choose the bank of 
> 32K that would be visible in the address space. I should reconsider the 
> schematic, and...
>> might make more sense if they went to Vcc where they would be diode blocked 
>> when the cart is on battery.
>>
>>
> Excellent suggestion.  I will do so.


With the 62256 drawing consequential standby current, you can't ensure an 
accurate calculated value for
the voltage division from specs as the chip current probably isn't a linear 
relation to Vcc.

But going from what we have:
Isb @ 5V Vcc = 0.5ma  then chip R = 5V / 0.0005A = 10 Kohms

2.7V Vbatt * 1 / (1+6800) = 1.6V across the chip supply pins.

But from the datasheet it also looks like Isb goes down considerably (40uA) if 
the voltage on nCS approaches Vcc
and other inputs pins go to 0V, as it might/would/should with the cart pulled.
That would be a higher effective R for the chip and so a higher V supply for 
the chip.

There is another potential problem with those switches though,
it's not clear to me whether you resolved whether X1P pins 1 & 27 connect 
together when plugged into the computer.
If not, then when plugged in and operational, the switch 10K Rs form a varying 
voltage divider with the 6.8K and the
input levels on bank-select address pins would be all over the place.

I would suggest you redraw the schematic with GND as the chip/computer GND
rather than establishing a second GND, and have a bus line across the bottom 
for the battery negative.

If you move the switches R supply it may be a good idea to put another diode in 
series to give a similar V drop as the main supply diode
so the V on the bank address pins doesn't go above the chip Vcc.

I'm not clear on what all is going on there between original design and 
modifications and additions.

Re: Types of corrosion on computers

[dwight via cctalk]

Could be the zinc plating?

Dwight



From: cctalk  on behalf of Sam O'nella via 
cctalk 
Sent: Friday, December 8, 2017 2:46:40 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Types of corrosion on computers

I've seen rust and dust, but there's an old vaxstation II at Goodwill
Computers in Austin right now (very cheap, anyone welcome to buy it and get
it off my mind) but as most things, I checked out the back and see some
circles of white corrosion on the back where the cards? are contacting the
case.

I don't really have room or time but I don't own anything that uses QBUS or
is almost related to some of the neat iron some of you all collect (I've
mostly collected way too many home computer history items).

Anyway, what is that type of white corrosion on metal?  Would one probably
assume this means any bus would be corroded and this wouldn't be a computer
for the faint of heart hobbyist? I've only seen that maybe from batteries
but it's in an unusual place and pattern (I think).

Re: Epson PX-8 specifically TF-10 problem...

[dwight via cctalk]

If it were a 5.25, I'd say it was the floppy sticking in the jacket.

Dwight



From: cctalk  on behalf of allison via cctalk 

Sent: Sunday, December 10, 2017 4:26:24 AM
To: Brent Hilpert via cctalk
Subject: Re: Epson PX-8 specifically TF-10 problem...

On 12/09/2017 09:14 PM, Brent Hilpert via cctalk wrote:
> On 2017-Dec-09, at 6:06 PM, allison via cctalk wrote:
>> On 12/09/2017 07:52 PM, Fred Cisin via cctalk wrote:
>>> On Sat, 9 Dec 2017, allison via cctalk wrote:
 I have several Epson PX-8s and i used them.. They work well with the
 various wedges I have.
 I also Have a PF-10 which is the portable 3.5" 40 track two side floppy.
 The problem is it randomly does not turn the media unless I give it a
 push to get it turning.
 Things checked:
 * Batteries, NEW fully charge (Both).
 * internal Power supplies, current voltage and bridged with external
supplies does not help.
 * media checked for binding, it does not.
  When it turns it reads and writes correctly and at the correct speed.
  It may do so without help for many tries then will stop required a
 manual push.
 At first glance I though there were motor bearing issues but have
 verified
 this is not so.   If I force motor on and restrain it I has good torque
 and no
 dead spots.  All signals in the motor control look good on the scope.
 Any thoughts?
>>> How does it detect the presence of a disk?   and/or disk change?
>>>
>>>
>> Functions normally save for the motor does not always turn on command
>> but will if manually pushed.  All other functions are normal.
> How about a problem with the current supply to the motor, such as low gain in 
> the driver.
> A progressive failure may be just on the edge of supplying enough current to 
> keep it rotating, but not enough for startup torque.

That was my thought and I checked, not the problem.  I suspect that the
magnets in the rotor
have gotten really weak.

Allison

Re: EPROM baking

[dwight via cctalk]

When I was at Intel, years ago, I recall the baking was only to repair the 
retention of the EPROMs. It was not to fix random failures.

It sounds like your EPROMs have various failures that wouldn't be helped by 
baking.

Each time the EPROM is programmed, there is a slight increase in the leakage of 
the floating gate. This was typical after thousands of program/erase cycles. 
Baking them repaired the damage to the insulating layer that was damaged.

Dwight



From: cctalk  on behalf of william degnan via 
cctalk 
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking

On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk@classiccmp.org> wrote:

> Hi,
>
> I am working on several projects requiring 2708 and 2716 EPROMs, and
> am finding some of my chips will not erase, and some will not take
> a program. I've also learned more in the past week than I wanted
> to know about repairing Data-I/O 29a/b programmers.
>
> I vaguely remember in the 1990s baking such EPROMs in the oven, but
> I do not remember temperature or time. I was surprised that Google
> didn't turn up anything useful with this info.
>
> I'm sure someone here will have some notes on EPROM baking.
>
> Mark
>
>
>

Mark,

If this is an issue about reviving bad eproms?  I assume you have tried the
regular stuff.

What process are you using now to erase 2708/16's?  I have a simple eraser
unit and it seems to always work.  Some eproms go bad but I never have
issues with erasing them.  My point is that maybe you need a better prom
eraser unit.  I would avoid baking them until you have exhausted other
options.  Not sure what others think.  This topic has come up before here,
about putting them outside and all that.  The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job?I assume there is more to it that
simply erasing them.


Bill

Re: EPROM baking

[dwight via cctalk]

If you've over voltages them, they are history.

If the ground pin is not making good contact and you try to program them, they 
will also be history.

Dwight



From: cctalk  on behalf of Pete Rittwage via 
cctalk 
Sent: Thursday, December 21, 2017 7:05:06 AM
To: Mark G Thomas; General Discussion: On-Topic Posts
Cc: cctalk@classiccmp.org
Subject: Re: EPROM baking

> Hi,
>
>> On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
>> cctalk@classiccmp.org> wrote:
>>
>> > Hi,
>> >
>> > I am working on several projects requiring 2708 and 2716 EPROMs, and
>> > am finding some of my chips will not erase, and some will not take
>> > a program. I've also learned more in the past week than I wanted
>> > to know about repairing Data-I/O 29a/b programmers.
>> >
>> > I vaguely remember in the 1990s baking such EPROMs in the oven, but
>> > I do not remember temperature or time. I was surprised that Google
>> > didn't turn up anything useful with this info.
>> >
>> > I'm sure someone here will have some notes on EPROM baking.
>> >
>> > Mark
>>
>> Mark,
>>
>> If this is an issue about reviving bad eproms?  I assume you have tried
>> the
>> regular stuff.
>>
>> What process are you using now to erase 2708/16's?  I have a simple
>> eraser
>> unit and it seems to always work.  Some eproms go bad but I never have
>> issues with erasing them.  My point is that maybe you need a better prom
>> eraser unit.
>
> They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
>
>> I would avoid baking them until you have exhausted other
>> options.  Not sure what others think.  This topic has come up before
>> here,
>> about putting them outside and all that.  The erasers are all over ebay,
>> and the hardware store is full of the correct types of lighting, why not
>> make a box that will do the job?I assume there is more to it that
>> simply erasing them.
>>
>>
>> Bill
>
> Erasing seems to work fine. It's the re-programming them that is the
> problem.
>
> On Wed, Dec 13, 2017 at 02:49:39PM +, dwight via cctalk wrote:
>> When I was at Intel, years ago, I recall the baking was only to repair
>> the retention of the EPROMs. It was not to fix random failures.
>>
>> It sounds like your EPROMs have various failures that wouldn't be helped
>> by baking.
>>
>> Each time the EPROM is programmed, there is a slight increase in the
>> leakage of the floating gate. This was typical after thousands of
>> program/erase cycles. Baking them repaired the damage to the insulating
>> layer that was damaged.
>>
>> Dwight
>
> I don't think these chips have been reprogrammed many times. It seems more
> age related, affecting some brands/models in my spares but not others.
>
> The failure mode is the chips erase successfully, but any attempt to
> program them fails, and they still test blank and read back "...".
> Some of these were chips I erased years ago before putting in my spares
> drawer, and some had fine working code on them, but I erased them to
> re-program with a newer version of software on them, to discover I could
> not.
>
> My stash of TI and NEC 2732s seem to have the disease, but my ST,
> Mitsubishi, and several others program fine.
>
> In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
> programmer and a modern Batronix programmer, with the same results.
> I don't think I have a programmer problem.
>
> I still swear someone in the late 80's had me baking EPROMs in an oven
> to restore their programability, but I don't remember the specifics. I
> tried a few at 450F for 15 minutes, but they still won't program.
>

Are you positive you have the programming voltage right? I have a box of
really old ones and every time I have to research a little to find the
right voltage for different brands. All 27128's are not the same, for
example. Some are 12V, some may be 25V (for example). My programmer only
has one setting in the software, and I have to change jumpers to modify
programming voltage. My USB programmer won't touch any of the old ones
because I assume it can't provide enough voltage/current for them.

-Pete Rittwage

Re: EPROM baking

[dwight via cctalk]

When I had access to a wire bonder, we took EPROMs that had been plugged in 
upside down and removed the lids. We'd see a blown wire and replace it.

On several of these parts we found that 100% worked. So it would seem that no 
silicon damage was done, just the bonding wire was blown like a fuse.

I doubt this method would repair those blown from excess programming voltage.

Dwight



From: cctalk  on behalf of Curious Marc via 
cctalk 
Sent: Friday, December 22, 2017 9:04:07 PM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking

I see the same things. Some chips just won't reprogram. Symptoms include 
failure to program just like you, but also "chip backwards" errors. Can't 
remember the chip brands, I just toss them out when that happens. I have not 
found any way to resuscitate them. Maybe ~10% of the chips I tried had this, so 
rather frequent, but never any from new old stock. The failed ones were all 
previously programmed chips, just erased.
Marc

On Dec 20, 2017, at 6:18 PM, Mark G Thomas via cctalk  
wrote:

My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.

In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.

I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.

Mark

--
Mark G. Thomas (m...@misty.com), KC3DRE

[cctalk] Re: IMSAI SIO 8080 Comm Program?

[dwight via cctalk]

Hi Bill
 I don't have one handy but you need to state how your SIO card is configured. 
The one I have, has a number of jumper options. I think we'd need to know the 
options for which bits are used for which.
Dwight


From: Bill Degnan via cctalk 
Sent: Sunday, July 23, 2023 6:52 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: Bill Degnan 
Subject: [cctalk] IMSAI SIO 8080 Comm Program?

I am looking for a basic or commercial IMSAI SIO 8080 Comm Program that
uses SIO serial connector 2 for modem communications.  Something I can
start from a ROM monitor running from the console running through serial
connector 1.

My system is using the original 8080, I want to avoid the cp/m z80 route.

Bill

[cctalk] Re: VCF this weekend, any one up for a trade?

[dwight via cctalk]

My Poly-88 should be working but I've not played with it for a few years. The 
last time I had it up and doing something was at the last MakerFaire .
What Is your issue?
Dwight


From: Steve Lewis via cctalk 
Sent: Thursday, August 3, 2023 10:19 PM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: Steve Lewis 
Subject: [cctalk] Re: VCF this weekend, any one up for a trade?

I can't make it to VCF this weekend - though I'm hoping to make it to the
one in September.

I actually am looking for something: any working IEC device for a C64 (1541
drive, printer, plotter?).   More for an experiment than collection, but do
prefer clean and presentable.


Earlier this year, I reached someone with a working Poly-88.  But then in
March they reported health issues and hospital stays, so I haven't heard
since.  Would be interested if anyone else is aware of a still-working one.

We're still working on recovery of an IBM 5100 "launch title" tape
(analytic functions) - practicing with other tapes first.  Its 2-channel
deal so far isn't quite that straightforward.  But if the Tektronics folks
can do it with their QIC tapes, I'm somewhat hopeful we can too (although
late 70s/early 80s Tektronic is apparently a more proper IEEE-488).

Only thing I could offer right now is a fairly not-working 5110 (display
don't work, PSU don't work, cards don't work - but the case is pristine).

-Steve





On Thu, Aug 3, 2023 at 8:49 PM Fred Cisin via cctalk 
wrote:

> >> I did not get any of whatever mailings there were.
> >>
> >> I don't exhibit, but I do have an excessive amount of stuff to sort and
> >> pack for sale and giveaway.
> >> --
> >> Grumpy Ol' Fred ci...@xenosoft.com
>
>
> On Thu, 3 Aug 2023, Sellam Abraham via cctalk wrote:
> > We'll just have to organize a VCF Fred at some point.  That way, they
> come
> > to you.
> >
> > I mean, after all, that's why I started the VCF ;)
>
> Yes, but you handed it over to a swell bunch of people before I finished
> parting with my stuff!
>
> --
> Grumpy Ol' Fred ci...@xenosoft.com
>

[cctalk] Re: Silly question about S-100 and video monitors

[dwight via cctalk]

I do understand the warranty sticker. Say we have the average computer buyer. 
He has a screw driver and mostly knows how to use it. He also went to Radio 
Shack ( long gone 🙁 ) and bought a cheap soldering iron. He is now fully 
equipped to repair what ever is wrong with his box. ( obviously not at Tony's 
level of competence ) He takes the cover off and has no idea what he is looking 
at or what he is looking for. ( I think we have all been there at one time ) He 
sees something with a screw driver slot. He has a screw driver. Perhaps all it 
needs is a minor adjustment. He turns the screw one way, and nothing changes. 
He turns it the other way and, pop, some smoke comes out of the other side of 
the chassis.
Oh well, it is under warranty so he goes to sends it in for warranty repair 
but, dang!, he broke that warranty seal.
If we want to have it repaired under warranty, we don't need to know what 
failed ( just curious ). If we expect to fix it ourselves, we bought it. There 
is value in learning how to fix it ourselves but the price is the warranty 
sticker. I except that and will open it up anyway. I just can't stop myself. I 
need to know what failed and often can fix it myself.
Dwight


From: Wayne S via cctalk 
Sent: Thursday, August 31, 2023 9:45 PM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: Wayne S 
Subject: [cctalk] Re: Silly question about S-100 and video monitors

I think you might be confusing a law argument with a logic argument.  🤓 The 2 
are not related.


Sent from my iPhone

> On Aug 31, 2023, at 21:00, Tony Duell via cctalk  
> wrote:
>
> On Thu, Aug 31, 2023 at 9:53 PM Chris Zach via cctalk
>  wrote:
>>
>> Which is weird, since Radio Shack was renowned for putting schematic
>> diagrams on so many of their products. My Flavoradio still has the
>> schematic on it if a transistor goes bad
>
> And they  would sell spare parts and service manuals for just about
> everything they sold.
>
> Their pocket computers were of course essentially re-badged Sharp and
> Casio machines. Getting the service manuals from the original
> companies was moderately harder than getting defence secrets. Getting
> the manuals from Tandy/Radio Shack was simply a matter of ordering
> them at the local shop.
>
> -tony

[cctalk] Re: Silly question about S-100 and video monitors

[dwight via cctalk]

My first computer was a Poly-88. I had no monitor and no keyboard.
I read and understood the instructions about finding a TV that used a 
transformer power supply. Many newer TV's of that day were not using a 
transformer for the main supply. I went to several secondhand stores and found 
one that would work.
The keyboard was from a surplus Singer data entry machine ( I thought they only 
made sewing machines ).
Dwight



From: W2HX via cctalk 
Sent: Wednesday, August 30, 2023 2:08 PM
To: William Sudbrink ; 'General Discussion: On-Topic 
and Off-Topic Posts' 
Cc: W2HX 
Subject: [cctalk] Re: Silly question about S-100 and video monitors

Ok great info, everyone. Thanks for the information!


73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos


-Original Message-
From: William Sudbrink 
Sent: Wednesday, August 30, 2023 5:06 PM
To: 'General Discussion: On-Topic and Off-Topic Posts' 
Cc: W2HX 
Subject: RE: [cctalk] Re: Silly question about S-100 and video monitors

Now that I'm thinking about it, there were also instructions for hacking the 
composite signal straight into the TV, bypassing the tuner... but Mom and Dad 
probably wouldn't go for that (mine didn't).

-Original Message-
From: William Sudbrink via cctalk [mailto:cctalk@classiccmp.org]
Sent: Wednesday, August 30, 2023 4:54 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'

Cc: 'W2HX' ; William Sudbrink 
Subject: [cctalk] Re: Silly question about S-100 and video monitors

There were RF modulators.  See the November 1976 review of the Poly-88 here (on 
page 16):

http://cini.classiccmp.org/pdf/DrDobbs/DrDobbs-1976-11-12-v1n10.pdf

Note the reference to the "Pixie Verter".  It is a little cheap circuit board 
that takes the composite signal and modulates it onto channel 3.  You will find 
references to the Pixie-Verter in a number of publications and user manuals for 
early video boards.  The Matrox and the Cromemco Dazzler and the Ohio 
Scientific documentation all reference it.  David Ahl in his "Saga Of A System" 
magazine article references it.  With that, a TV, video board, RF modulator and 
a parallel keyboard were much cheaper than any serial terminal back then.  The 
RF modulator was separate from the video board (usually hung on the back of the 
TV) for noise reasons.



-Original Message-
From: W2HX via cctalk [mailto:cctalk@classiccmp.org]
Sent: Wednesday, August 30, 2023 3:39 PM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: W2HX 
Subject: [cctalk] Silly question about S-100 and video monitors

Hi all,

I recently acquired an S-100 computer, and it came with a video card and a 
keyboard (3rd party products, not originally equipped with these). I am trying 
to figure out the benefits of having a video card and keyboard vs just using a 
serial port and terminal. Certainly if the video card supported graphics, that 
would be a reason to go that route over a terminal. As for the keyboard, 
ok-maybe you need specific keys for a specific application.
But I don't understand the video monitor. I could understand maybe if there was 
an RF modulator so that you could use a standard TV. That would save the 
builder some money. But this computer just provides composite.

Other than graphics (and maybe some special function keys for an application on 
a keyboard), why would an S-100 builder in those days opt to buy a video card 
instead of a terminal?

Thanks for the bandwidth.

73 Eugene W2HX
Subscribe to my Youtube Channel: https://www.youtube.com/@w2hx/videos


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[cctalk] Re: Friden (was Silly question about S-100 and video monitors)

[dwight via cctalk]

I like OSHPark. They are not the cheapest but they also would drill tightly 
spaced feed thru's that I could pass wire wrap wire through ( uninsulated ). I, 
also, didn't need to create Gerber files for drilling ( always a possible 
source of errors from a past place I worked at ).
I used KiCad.
Their boards were purple, if that meets your fancy.
Dwight


From: Paul Koning via cctalk 
Sent: Sunday, September 3, 2023 1:28 PM
To: cctalk@classiccmp.org 
Cc: Paul Koning 
Subject: [cctalk] Re: Friden (was Silly question about S-100 and video monitors)



> On Sep 2, 2023, at 3:49 PM, ben via cctalk  wrote:
>
> On 2023-09-02 8:01 a.m., Will Cooke via cctalk wrote:
>>> On 09/02/2023 8:50 AM CDT Peter Corlett via cctalk  
>>> wrote:
>>>
>>>
>>> On Fri, Sep 01, 2023 at 04:32:57PM -0600, ben via cctalk wrote:
>>> [...]
 I think that way has been for a while. Having a hard time finding a 68B50
>> Unicorn Electronics has the 68B50 for $7.99
>> https://www.unicornelectronics.com/IC/6800.html
> $ 30 mininum order and 4 weeks shipping to canada stopped me.
> $12.06 US from china. (ebay).
> I am having my PCB's made from PCBWAY in china. Shipping takes longer
> than them being made. ~ $100 US for the PCB's and ~ $50 for shipping and tax.

I like OSHPark, US based and pretty quick, decent pricing.  Low enough I 
haven't felt compelled to look for cheaper alternatives.  One nice feature is 
that they take KiCAD board files directly, no need to generate the low level 
Gerber files.  One oddity is their purple (or black) solder mask, but one gets 
used to it.  2 or 4 layers and some other variations.

paul

[cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs rescue...

[dwight via cctalk]

I have an older one and it seems like, I recall, openboot has a name for the 
nvram. possible caMel or similar.
Dwight


From: erik--- via cctalk 
Sent: Sunday, September 24, 2023 1:35 PM
To: cctalk@classiccmp.org 
Cc: e...@baigar.de 
Subject: [cctalk] Re: Tadpole/RDI UltraBooks - UNIX notebooks - species needs 
rescue...

Played a little around - and the OpenFirmware's "dump" command on my older 
SparcBook 3GX (so no Ultra, but 4m architecture) is able to dump virtual 
memory. Obeying to the forth syntax, the following command...

1000 100 dump

...dumps 256 bytes starting at address 1000. Of course, reading undefined 
(=unmapped) memory leads to an access violation. But as the firmware manual 
describes, devices can be selected and than it is possible to dump their 
io-space and I bet somewhere in there, the NVRAM is hidden. At ffee I see 
populated memory in the 3GX - the dumpable range starts at ffee and ends at 
ffef (in total 128k). So having a running UltraBook that would be the way 
to seach for the NVRAM?

[cctalk] Re: Intel 4004

[dwight via cctalk]

There is little surviving software for the 4004. There are a few places with 
snippets of code to do things like add or subtract several digits but my 
searches of the internet have shown little actual code. The NBS has some code 
to track satellites and correct for time delays from their clocks ( think GPS ).
I'd had a spare 4004 and always wanted to do something with it. I found that 
the library for work done at the Navy Post Graduate School in Monterey 
California had 2 projects that students of Gary Kildall created. One was a load 
calculator for helicopters and the other was for calculating closest point of 
approach for ships. I'd been unsuccessful at down loading the helicopter code 
but was able to down load the ships document.
I'd let the listing sit for 10's of years while always on the back burner. Over 
the years I'd acquired the needed parts. I did make a few substitutions, 
though. The original used 13 each 1702A EPROMs. Since that exceed my budget for 
a PC board space, I chose the option of using a 4289 and a 2732 EPROM. I did 
use the original designs number of 4002s, as using RAM through the 4289 would 
have made significant changes to the software.
The problem of the circuit needed to be dealt with. The document had a page 
labelled 'schematic' that turned out to be the keyboard layout and display 
layout( both of which I ignored and used my own layout that I though was better 
).
Before getting to the board design, I needed to get working software. The 
listing was done on a ASR33 with a deeply rutted platen, typical of 
hand-me-down things used by a school's command. Letters like R or P would look 
like F and 0 would look like C. Other letters were easy to figure out but still 
often had their right edge missing.
After entering the list by hand, I'd feed it into my assembler and the tried to 
run it with my simulator.
I'd make corrections as I got the code running.
I need to create the circuitry for the keyboard decoder, that took 25 buttons 
to the 4 bit data bus input of the 4004. There was enough description in the 
document to create the LED display but I did missed one thing ( that I'll 
mention later ).
I created the board with my typical incorrect wiring, requiring several extra 
cuts and jumpers. ( the concept was right but I got the pins of the 7402 mixed 
up.) The one thing that I'd missed was the order of the digit scan. I assumed 
left to right but the code was actually right to left. After so many cuts and 
jumpers to get the keyboard right, I dreaded more to fix the scan order so I 
made the one change to the original software to do right to left ( I still feel 
bad about that change ).
I thought I'd talk a little about how a Closest Point of Approach Calculation 
is done. Normally it had been done by a graphical method of line drawing on 
what is called a plotting maneuver board. One used graphical calculations for 
the trig used. It was all done by pencil and parallel. It is so important that, 
I believe, that to this day a ship's pilot still needs to be able to do this 
calculation on a maneuver board, even though such graphical displays are 
capable of doing such, today. Large ships require significant knowledge of 
where they are relative to other fixed and moving objects in order to determine 
the safest path to proceed. A broken display is not time to learn how to do 
such a calculation.
This 4004 calculator used a newly found way of doing tangent calculations, 
called the CORDIC method. One could clearly see the influence of Gary Kildall's 
hand in this code. It is noted that he wrote the division routine used and the 
organization of the code clearly shows the influence of a seasoned programmer. 
Bring such code back to life was almost as much as making a 4004 processor from 
discrete transistors but I felt was for me as part of my bucket list.
Things I needed to do, included writing an assembler, writing a simulator, 
learn a PC board CAD, transcribing a poor quality listing, debugging the poorly 
transcribed listing, creating the keyboard decoder and instrumenting my 
simulator to be the calculator.
Dwight



From: ED SHARPE via cctalk 
Sent: Tuesday, November 21, 2023 1:03 AM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: ED SHARPE 
Subject: [cctalk] Re: Intel 4004

So what are the other contenders and what do they bring to table


Sent from AOL on Android

  On Mon, Nov 20, 2023 at 9:06 PM, Adrian Stoness via 
cctalk wrote:   someone should build it in minecrsft

On Mon, Nov 20, 2023 at 7:01 PM ben via cctalk 
wrote:

> On 2023-11-20 5:36 p.m., Murray McCullough via cctalk wrote:
> > On Nov. 15, 1971 Intel commercially released the 4004 microprocessor
> which
> > some consider to be the first. Nonetheless, even if not in agreement, it
> > made possible the instrument which drives the classic-computing industry
> or
> > at the very least our hobby!
> >
> > Happy computing.
> >
> > Murray 🙂
>
>
> https://retrocomputin

[cctalk] Re: Intel 4004(sp?)

[dwight via cctalk]

The Intlec 4 was no more or less a computer than the Altiar or IMSAI was. It 
didn't typically have as much RAM but one could write and run code on it.
As for the F14 processor. For the purpose used, it was likely a DSP. More 
intended to do matrix multiplication using adds and shifts. This would be 
similar to Intel's early try at a DSP.
The F14 processor was said to control the flight surfaces. Like the Intel 2920 
( not to be confused with the AMD bit slice part) it likely ran tight loops of 
signal processing operations using tables of lookup coefficients.
Dwight

[cctalk] Re: Intel 4004(sp?)

[dwight via cctalk]

The 4040 was more of an enhanced 4004. It had a deeper stack ( 4004 was only 3 
levels ), It had interrupt capabilities and a second register bank.
The mulplexed bus was almost identical except the 4040 had one additional bus 
operation. I forget the exact difference.
Still, people seem to think that the 4004 wasn't a capable microprocessor. 
Benchmarks showed that much code was faster on the 4004 than the 8008, if 
working in BCD math.
The main reason the 4004 was thought of as just a calculator chip was that the 
chipset that it originally came with, the ROM and RAM, was to use a minimal 
additional amount of custom bus circuity for the Busicom project. I guess it 
wouldn't be a real uP if one didn't have to create bus buffers and address 
decoders.
As an example, Tom Pittman wrote a two pass assembler that ran on the SIM4-01( 
4ea1702.s or 1k of code! ). That seems to be a uP type of process, to me. I 
should note that Tom's code won't run on a 4040 without modification. This was 
because he took advantage of the fact that the stack would overflow on the 
fourth subroutine push. The 4040 had a deeper stack. Still, the 4004 could 
handle text as well as do calculations.
Probably, the main thing that tended to put it in the calculator bucket was the 
restricted instruction memory range, without using some form of bank swapping. 
Its natural memory range was limited to 4096 addresses. But then, the 8080 was 
considered a real uP with similar restrictions to 64K.
Both the 4004 and the 8008 used a multiplexed bus, for the 8008, one had to 
design their own bus interface. The 8080 was what made the type of uP we tend 
to think of. It had separate data and address busses ( note the 8085 and 8086 
both multiplexed the address and data buses. A step back I'd say. )
I'd say things really started to happen when they created the 6502. That 
brought the pricing into a range that people could start small and expand to 
bigger things.
Dwight



From: ED SHARPE 
Sent: Wednesday, November 22, 2023 7:43 PM
To: General Discussion: On-Topic and Off-Topic Posts 
Cc: dwight 
Subject: Re: [cctalk] Re: Intel 4004(sp?)

Ibad an intellectual 4 offered to me one time that had a 4040 in it. Is t a 
4040 like a 5 but more of the aux chips integrated? Is instruction set the same?

Sent from AOL on 
Android<https://play.google.com/store/apps/details?id=com.aol.mobile.aolapp>

On Wed, Nov 22, 2023 at 8:34 PM, dwight via cctalk
 wrote:
The Intlec 4 was no more or less a computer than the Altiar or IMSAI was. It 
didn't typically have as much RAM but one could write and run code on it.
As for the F14 processor. For the purpose used, it was likely a DSP. More 
intended to do matrix multiplication using adds and shifts. This would be 
similar to Intel's early try at a DSP.
The F14 processor was said to control the flight surfaces. Like the Intel 2920 
( not to be confused with the AMD bit slice part) it likely ran tight loops of 
signal processing operations using tables of lookup coefficients.
Dwight

[cctalk] Re: WWVB

[dwight via cctalk]

I'm in San Jose, Calif. I have a cheap clock that I picked up at a garage sale. 
It being a cheap clock, uses a ferite rod, so is quite directional. Also, I 
need to place it in a window as well. It seems to pick up the signal at least 
once a day, most likely after dark.
Mine blinks the antenna signal when it thinks it is receiving the signal and 
then has a solid one when it updates, for a day. These are all different so 
your milage may vary.
Dwight



From: Robert Feldman via cctalk 
Sent: Monday, January 15, 2024 12:17 PM
To: cctalk@classiccmp.org 
Cc: Robert Feldman 
Subject: [cctalk] Re: WWVB

>Message: 17
>Date: Mon, 15 Jan 2024 12:52:15 -0500
>From: Bill Gunshannon 
>Subject: [cctalk] Re: WWVB
>To: cctalk@classiccmp.org
>Message-ID:  
>Content-Type: text/plain; charset=UTF-8; format=flowed
>
>On 1/15/2024 10:47 AM, Chris Elmquist via cctalk wrote:
>> On Sunday (01/14/2024 at 09:55PM -0600), Chris Elmquist via cctalk wrote:
>>> There are a number of WWVB simulator projects out there that will transmit 
>>> a weak but usable signal to your clock after getting sync’d from ntp or GPS 
>>> NMEA time messages.  They were developed to help people develop receivers 
>>> :-)   One in particular uses an AVR and it should be pretty simple to make 
>>> it do the “old protocol”.  You’d then hide this behind your clock and it 
>>> will sync to it instead of the actual WWVB signal.  Solves the protocol 
>>> problem and the weak signal problem from real WWVB with one little circuit.
>>>
>>> If Google does not provide, I can dig up some links tomorrow.
>>
>> Hmm. Strange.  I did follow-up shortly after the above post with this
>> link,
>>
>> https://www.instructables.com/WWVB-Simulator/
>>
>> but I don't see that that made it to the list.
>>
>> Chris
>>
>
>It did.  I got it.
>
>bill

Your original email with the link did not make it into the digest, which is 
what I receive.

Chirs, Did you also send it directly to Bill. Perhaps that is what he got.

Bob

[cctalk] Re: Z80 vs other microprocessors of the time.

[dwight via cctalk]

From: ben via cctalk 
Sent: Monday, April 22, 2024 12:43 PM
To: cctalk@classiccmp.org 
Subject: [cctalk] Re: Z80 vs other microprocessors of the time.

On 2024-04-22 1:02 p.m., Chuck Guzis via cctalk wrote:

> I'd like to see a Z80 implemented with UV-201 vacuum tubes... :)
> --Chuck

Real computers use glow tubes like the NE-2 or the NE-77.:)

For those that don't know what a UV(UX)201 was, it was most commonly used for 
audio amplification in early battery powered radios. These used a lot of 
filament current, not like later miniature tubes.
They had a UV(UX)200 tube for RF detections that worked better as a grid leak 
detector, I think because of less cutoff voltage needed as a detector.
The A series used a better getter and lower current filament ( one or both? ) 
but still used a lot of filament current.
Dwight

[cctalk] Re: First Personal Computer

[dwight via cctalk]

I'm not claiming it was the first personal computer but is was my first 
personal computer. It was within a year or two of just about any other first 
personal computer.
It was a Poly88 with ROM based tiny basic. I had a keyboard, I think I got from 
Mike Quin's as well as a Singer typing terminal that I converted into a serial 
printer.
I used a transformer powered TV as a monitor and used a cassette recorder as 
mass storage.
It was more personal than other machine as it was my personal creation after 
several modifications to enhance it. I learned a lot about computers and how 
they worked from that machine.
Dwight

[cctalk] Re: Intel 8086 - 46 yrs. ago

[dwight via cctalk]

No one is mentioning multiple processors on a single die and cache that is 
bigger than most systems of that times complete RAM.
Clock speed was dealt with clever register reassignment, pipelining and 
prediction.
Dwight

[cctalk] Re: Value of Intel MDS System

[dwight via cctalk]

Sounds like a MDS 800. Separate drive box and machine.
If it is, it is a Multibus system. It likely has a 8080 processor but could 
have been upgraded to a 8085. It might have a 8086 but it would likely still 
have the 8080 as the boot processor.
Unless it was upgraded to something else, it would have a fm or m2fm disk 
controller.
Key board and display would likely be a Beehive ( an excellent terminal ) but 
it could be most any serial terminal.
It would likely boot to ISIS II from disk.
Which boards it has would be intersting.
Dwight



From: Marvin Johnston via cctalk 
Sent: Friday, July 12, 2024 8:29 PM
To: cctalk@classiccmp.org 
Cc: Marvin Johnston 
Subject: [cctalk] Value of Intel MDS System

In keeping with a previous discussion about reducing a collection  size,
I have an intel MDS system I am kind of looking to sell. This system
consists of the processor box, dual floppy drives, two keyboards (one
missing a keycap), and monitor. Unfortunately, no manuals or software
came with it when I got it some 30 or so years ago. Also I have never
powered it up and won't since it has been sitting for a long time and
will need a careful checkout to make sure it is safe to power up.

I do plan on attending VCFMW in early September, and can bring it with
me (and Sellam) for pickup at the show. My route will be I5 to I80 from
California so it might be possible for the buyer to make arrangements
with us to transfer the unit to the buyer along the way. Generally
speaking, there won't be much time along the way since I generally drive
24/7 except for short stops for gas and rest as needed

Long winded way of asking here has anyone a clear idea of what to
charge. It has been sitting in my garage since I acquired it.

Marvin