Re: Resistor/Fuse replacement (DEC H7104-D)

[Mattis Lind]

2016-03-22 20:47 GMT+01:00 Noel Chiappa :

> > From: Josh Dersch
>
> > I have no excuse, I just get nervous working on these things.
>
> I should hope you do get nervous! Anytime one is working around equipment
> that
> contains lethal voltages, one _should_ be nervous! It helps with...
>

Don't work with lethal voltages! Use a insulation transformer. Then it is
not as likely to kill you unless you brake the rule and put both your hands
in the supply. Then use a variac. My experience is that you can observe the
behaviour at a much lower voltage when the load is small. This supply if I
remember correctly will work fine from 60 VDC at the input caps.

I do this all the time. I am not nervous when putting the scope-probe on
anything in there.

One more thing regarding the H7104. The circuit that enables the relay will
also enable the signal to the main chopper transistors. Thus there will be
no switching at all unless the input voltage is above 250VDC or so. I
disabled this circuit for testing purposes. As long as the load is small
this should not cause any problems. (And since I tested I know it didn't)

>
> > I suppose eventually I'll get used to it.
>
> Don't get too used to it, one wants to always be aware and cautious!
>
> (I myself am missing half a nail - and I'm lucky that's all that's missing
> -
> because I got too "used to" working with my table saw...)
>
> Noel
>

/Mattis

RE: Looking for I/O specs HP 9000/236 - 9836CU

[Rik Bos]

> -Oorspronkelijk bericht-
> Van: cctalk [mailto:cctalk-boun...@classiccmp.org] Namens Pete Lancashire
> Verzonden: woensdag 23 maart 2016 4:24
> Aan: General
> Onderwerp: Looking for I/O specs HP 9000/236 - 9836CU
> 
> I just acquired one of the guys w/o a display
> 
> Looking for the spec's of the display connector.
> 
> I have what I believe to be the pinout but nothing on timing, scan rates, 
> levels
> etc.
> 
> Other identification on the thing is
> 
> "1 MB Board internal set as 1st Card"
> 
> Upgraded to 9836CU
> 
> NO BATT / DOES NOT START / BOOT ?
> 
> Model ID tag 9836C / 2210A01010
> 
> -pete

Pete,

Tony, reverse engineered the HP 9836C (and a lot of other HP equipment)  he 
made the diagrams available through the HPCC.
It's part from a great collection of HP diagrams including calculators 
computers and peripherals etc..
http://www.hpcc.org/cdroms/index.html

-Rik  

RE: Looking for I/O specs HP 9000/236 - 9836CU

[tony duell]

> Tony, reverse engineered the HP 9836C (and a lot of other HP equipment)  he 
> made the diagrams available through the HPCC.
> It's part from a great collection of HP diagrams including calculators 
> computers
> and peripherals etc.. http://www.hpcc.org/cdroms/index.html

It was decided by the HPCC committee to no longer send out physical CD-ROMs for 
this. Instead members (only) can download the latest version free of charge. A 
year's 
membership of HPCC is not much more than the only cost of the CD-ROM, and you 
have the other benefits of HPCC.

The HP9826/36 schematics can be downloaded from the Australian HP museum, 

http://www.hpmuseum.net/ 

They are under the HP9826, there is so much in common between the machines that
I produced one set of diagrams for both. I did the 3 machines I have, a 9826, a 
9836A
and a 9836CU. Yes, I did include monitors, etc.

-tony

RE: Looking for I/O specs HP 9000/236 - 9836CU

[tony duell]

> 
> I just acquired one of the guys w/o a display
> 
> Looking for the spec's of the display connector.
>
> I have what I believe to be the pinout but nothing on timing, scan rates,
> levels etc.

If it is a CU -- that is it has a colour video board set in it -- then it is a 
bit 
strange. There are a pair of TTL level syncs, I can't remember the frequencies
but something tells me it's close to TV. It's also easy to measure with a 
frequency
counter.

The 3 colour signals are analogue current sinks on the machine, not voltage 
level outputs. No normal monitor will connect directly. You need a bit of 
analogue
electronics to sort it out. 

> Other identification on the thing is
> 
> "1 MB Board internal set as 1st Card"

This may mean somebody has fitted a 1M RAM card into
the normally unused internal slot and that it is set for the top of memory 
(which would be logical).

You need to take off the cover (the 4 largest screws on the bottom, behind
the keyboard area) and see just what is in there.

> Upgraded to 9836CU

Probably the CPU board was replaced by the 68010/MMU one.

> NO BATT / DOES NOT START / BOOT ?

May mean it doesn't have the battery backup option (I've never seen it)
and that there is some other fault too...

-tony

TI Silent 743/745 question.

[Cohen, Corey A]

I'm trying to troubleshoot a TI silent 743/745.   When you press the "rubout" 
key should it print anything like an underscore?   Besides sending the rubout 
character, what does the actual print head do?  Backup? Print an underscore?

Thanks,
Corey

corey cohen
uǝɥoɔ ʎǝɹoɔ
Mobile: +1 917 747 1408

Re: TI Silent 743/745 question.

[Chris Elmquist]

On Wednesday (03/23/2016 at 02:03PM +), Cohen, Corey A wrote:
> I'm trying to troubleshoot a TI silent 743/745.   When you press the "rubout" 
> key should it print anything like an underscore?   Besides sending the rubout 
> character, what does the actual print head do?  Backup? Print an underscore?

I get nothing printed when pressing RUBOUT.

With the unit in off-line mode and in half- or full-duplex, characters
typed are printed.  RUBOUT prints nothing.

With the unit in on-line mode and half-duplex, chraracters typed are
printed and RUBOUT prints nothing.  In full-duplex, nothing prints unless
the far end echos it back.

Chris
-- 
Chris Elmquist

Re: TI Silent 743/745 question.

[Chris Elmquist]

On Wednesday (03/23/2016 at 09:25AM -0500), Chris Elmquist wrote:
> On Wednesday (03/23/2016 at 02:03PM +), Cohen, Corey A wrote:
> > I'm trying to troubleshoot a TI silent 743/745.   When you press the 
> > "rubout" key should it print anything like an underscore?   Besides sending 
> > the rubout character, what does the actual print head do?  Backup? Print an 
> > underscore?
> 
> I get nothing printed when pressing RUBOUT.
> 
> With the unit in off-line mode and in half- or full-duplex, characters
> typed are printed.  RUBOUT prints nothing.
> 
> With the unit in on-line mode and half-duplex, chraracters typed are
> printed and RUBOUT prints nothing.  In full-duplex, nothing prints unless
> the far end echos it back.

I should have elaborated a little on what you might be seeing.
If something does print when you hit RUBOUT and you are on-line and in
half- or full-duplex, it is possible that the far end, whatever host
you are connected to, is echoing something back in response to the RUBOUT.

The terminal sends ASCII 0x7F when you press RUBOUT.  This is a non-printing
character locally but the remote system can send back whatever it likes
in response to receiving that 0x7F.

Chris
-- 
Chris Elmquist

Re: TI Silent 743/745 question.

[william degnan]

On Wed, Mar 23, 2016 at 10:37 AM, Chris Elmquist  wrote:

> On Wednesday (03/23/2016 at 09:25AM -0500), Chris Elmquist wrote:
> > On Wednesday (03/23/2016 at 02:03PM +), Cohen, Corey A wrote:
> > > I'm trying to troubleshoot a TI silent 743/745.   When you press the
> "rubout" key should it print anything like an underscore?   Besides sending
> the rubout character, what does the actual print head do?  Backup? Print an
> underscore?
> >
> > I get nothing printed when pressing RUBOUT.
> >
> > With the unit in off-line mode and in half- or full-duplex, characters
> > typed are printed.  RUBOUT prints nothing.
> >
> > With the unit in on-line mode and half-duplex, chraracters typed are
> > printed and RUBOUT prints nothing.  In full-duplex, nothing prints unless
> > the far end echos it back.
>
> I should have elaborated a little on what you might be seeing.
> If something does print when you hit RUBOUT and you are on-line and in
> half- or full-duplex, it is possible that the far end, whatever host
> you are connected to, is echoing something back in response to the RUBOUT.
>
> The terminal sends ASCII 0x7F when you press RUBOUT.  This is a
> non-printing
> character locally but the remote system can send back whatever it likes
> in response to receiving that 0x7F.
>
> Chris
> --
> Chris Elmquist
>
>
What happens when you're in 20 mA mode?  That's what it's for, not serial
comms unless it's mapped specially.  i.e. it's for emulating a teletype.
right?

-- 
@ BillDeg:
Web: vintagecomputer.net
Twitter: @billdeg 
Youtube: @billdeg 
Unauthorized Bio 

Re: TI Silent 743/745 question.

[Chris Elmquist]

On Wednesday (03/23/2016 at 12:57PM -0400), william degnan wrote:
> >
> > The terminal sends ASCII 0x7F when you press RUBOUT.  This is a
> > non-printing
> > character locally but the remote system can send back whatever it likes
> > in response to receiving that 0x7F.
> >
> What happens when you're in 20 mA mode?  That's what it's for, not serial
> comms unless it's mapped specially.  i.e. it's for emulating a teletype.
> right?

Both of my units are 745 with EIA interface, internal acoustic coupler
and no 20mA.  But checking the manual, I don't see any way that you choose
"20mA mode".  It's not a switch or input to the processor that might
change the firmware behavior.  So I don't think what gets sent on 20mA
would be different than what gets sent on EIA when you press RUBOUT...

A lot of systems in that era used RUBOUT like a backspace operator.
If the terminal sent RUBOUT, the host/OS would interpret that as a
delete character operation and then echo back a backspace, maybe an X,
then accept the new input character.

https://en.wikipedia.org/wiki/Delete_character

Chris
-- 
Chris Elmquist

FS: Fulcrum IMSAI 8080 clone system

[Sellam Abraham]

I'm selling this interesting off-shoot of IMSAI history.  It's a Fulcrum 
Data Systems IMSAI 8080 clone in turnkey configuration.  Fulcrum was 
started by Bruce Wright of WW Component Supply, who competed with 
Tom Fischer to buy remaining inventory at the IMSAI bankruptcy sale in the 
early 1980s.  Fulcrum was eventually sued and had to cease and desist but 
not before a few of these systems were sold.

Photos and more information are located here:

http://vintagetech.com/sales/S-100/Fulcrum/

It powers up but I haven't tested the logic.  The bus power is fused and 
I don't have the fuse caps right now.  I can probably round some up with a 
little scrounging.  Otherwise I tested all the voltages coming off of the 
power supply and they are good.

I'm asking $1,200 for the complete system (CPU + dual drive unit) but I'm 
willing to entertain offers.

Please inquire directly via private e-mail.  You might also want to check 
out the other stuff I have for sale by starting here:

http://vintagetech.com/sales/

Thanks!

--

Sellam Abraham VintageTech
--
International Man of Intrigue and Dangerhttp://www.vintagetech.com

Whatsoever a man soweth, that shall he also reap.  The truth is always simple.


   * * * NOTICE * * *

Due to the insecure nature of the medium over which this message has
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reliable for any purpose either express or implied.  The contents of
this message are appropriate for entertainment and/or informational 
purposes only.  The right of the people to be secure in their papers
against unreasonable searches and seizures shall not be violated.

Opening up PSU for Olivetti M24

[Robert Jarratt]

I have just acquired an Olivetti M24. I want to inspect the PSU and I have
removed it from the machine. But I am struggling to remove the only
seemingly removable panel. This is the one with the mains socket and the
on/off switch on it. It looks as if it might be hinged at the bottom, but it
won't pivot out or come away. Does anyone know how to get inside this PSU?

 

Thanks

 

Rob

PDP-8 panels

[Rod Smallwood]

Hello Guys.
To say I'm pleased with the comments on the batch 
just shipped would be an understatement.

However you cant just rest on your laurels.

_Batch now in production_

The next batch is already underway and the quantity increased to thirty,
It will consist of 8/e (A and B), 8/f and 8/m .All the artwork is done 
and ready


I'm trying to get to a ship from stock situation but I keep getting 
pre-orders (not that I mind!!)


_The PDP-8  Product Line So Far_

PDP-8/e (A)  before the switch change
PDP-8/e (B)   after the switch change

PDP-8/f
PDP-8/m

We also offer to change the address from the standard maynard to galway.
If you find any other address variations I'd be interested.to consider 
them as well.



_PDP-8 New Products under consideration _

1. Front panels for any of the other PDP-8 models, Including the 
Straight 8 but excluding PDP-8A.


2. Bezels either cast metal as existing or a tough plastic.
 The metal ones are big and heavy and awkward to ship.

3. Programmers Console PCB (key and lamp unit) / emulator

4. Integrated version of  1 + 2 above

5. Integrated version of  1 + 2 + 3 above

_
__PDP-11 Product Line_

1. Artwork underway for 11/XX panels (11/70 style)

2. No launch date yet but not a long way off.



_DEC unlisted above or non CPU panels._

I'll look at  anything DEC made that uses a flat substrate (Plastic, 
Metal or Glass) and has screen printing



_Non DEC panels
_
I'd be intersted in panels from other makers using similar substrates 
and screen printing.



I think thats the lot

Regards

Rod (Panelman) Smallwood



_
_

DEC H7104-D debugging...

[Josh Dersch]

On 3/22/16 12:29 AM, Mattis Lind wrote:

such good luck.  No smoke or fire, but now I get nothing at all out of the
supply.  The whine is gone, but there's nothing output at all.  The
fuse/resistor didn't blow (it's still got continuity across it) and the
transistor I replaced is still fine, but there must be something else in
the supply that's causing issues...

Blargh.  I hate working on power supplies.


In this case you have an excellent technical manual and a good schematic
which should help a lot. Working with big SMPSU without schematics or
technical manuals is a not fun.

So here is my piece of advice directly from my head.

1. The PSU has really two AC inputs wired together in the input harness.
You can separate the startup supply part from the SMPSU part. Connect the
startup PSU to a separate AC input and the SMPSU part to a insulation
transformer, a variac and lightbulb in series.
2. Check that the startup PSU, that uses a normal 50/60 Hz transformer
gives the correct voltage. +11 if I remember correctly.
3. There is a circuit that monitors the input rectified 300VDC voltage and
enables the relay when it has reached a proper voltage. It is a soft start.
Disable it for temporarily. Good idea to check that is working though. If
not the soft start resistors will become overheated when trying to run it
at full load.
4. Now you need to have the SMPSU section connected to AC inlet. On one of
the daughter boards there is a switching bias supply. Check that it
generates the +/-12 V and +5V.
5. Is the main SMPSU switching logic making a nice square wave signal
output. The control board is yet another daughter board.
6. I disconnected the output terminals from the H-bridge to the transformer
and connected a dummy load to be able to have a look at the output waveform.
7. Reconnect the transformer. The main switch produces +5V and +38V. The
38V is then used on the daughterboards to create all the other voltages,
+/- 12V, +/- 15V, +12V SB, +5VSB (depending on which supply). Is there 38V
here?
8. There is a crowbar circuit on the +5V output terminals. Check that it is
not tripping.


Please note that when working with the +2.5V supply it gets the bias
voltages from the +5V supply. So either get that one working first or
supply bias voltage from a regular PC supply.

/Mattis


So I had a few minutes tonight to investigate a few things:

- The startup PSU is running, and the relay in the 5V supply is firing 
and stays energized until the supply is powered off.
- The +5V, and +/-12V bias voltages are being properly generated. This 
makes sense, since the 2.5V supply is working fine.  From my 
understanding of the supply, this means the 300VDC is also present (also 
validated by the relay firing.)
- The 20Khz clock generated on the bias board is present (measured from 
pin 8 of J1 on on the bias board), at the proper rate and duty cycle.

- 5V AC and DC LO signals (measured at J1) are .3 and .9V, respectively.

So far, so good.  I also measured the 5V Overcurrent and 5V Crowbar on 
J1 (pins 2 and 19) and they're at 12V and 8V respectively.  I'm not sure 
I understand what this indicates; the Overcurrent lamp is not 
illuminated on the power controller, for example, and per the tech 
manual (section 4.4.2) if an overvoltage occurs and the crowbar kicks 
in, the supply should shut down for ~1 second, which I'm not seeing any 
indications of (I'm not seeing the voltage reach anything over .2V with 
a small load attached).  The overcurrent protection appears to work 
similarly.  I don't see an indication of what the levels for the signals 
on J1 are supposed to be, however.


I'll hopefully have more time to debug later this week, thought I'd 
report my findings and see if anyone has any bright ideas.


Thanks as always,
- Josh

Re: Reproduction 8/e panel from Rod Smallwood

[Mike Barnes]

On Fri, Mar 18, 2016 at 8:00 AM, Michael Thompson <
michael.99.thomp...@gmail.com> wrote:

> I received my reproduction 8/e panel from Rod Smallwood (aka "panelman")
> this week. It looks spectacular compared to the peeling paint on the
> original. Rod did not drill the hole for the rotary switch because the
> position varies a little depending on the revision of the switch panel. I
> put the original panel on top of the new one, marked the rotary switch
> location, drilled a pilot hole and successively larger holes. I had to
> adjust the position of the AC power switch a little to optimize the
> clearance around the switches, but that was easy.
>
> The original panel had rubber bumpers between the panel and the front of
> the chassis that I will attach to the new panel with double sided adhesive
> tape. The original panel had a tapered relief at the back of the hole for
> the AC power switch, but the new one does not. I will use a file or Dremel
> tool to remove some of the panel material. Without the relief the panel
> will get stressed near the AC switch.
>
> Overall, the workmanship on the panel is spectacular. Now I need to repaint
> the 8/e front panel frame, RX01, RK05, and TU56 so they look as nice as the
> new front panel.
>
> --
> Michael Thompson
>

I concur. Mine arrived this week and it's more of a work of art than a
computer panel.
Absolutely stunning. Kudos to Rod and his professional silk screeners for
making this
available.

Mike