On 2022-Jan-06, at 12:19 AM, Joshua Rice via cctech wrote:
> Not cost effective at nearly $10,000! I understand they're very rare, given
> they were only used for a few years in industry and they're clocking on 3/4
> of a century old, but even then, that seems an order of magnitude or two off
>
On 2022-Jan-06, at 12:19 AM, Joshua Rice via cctech wrote:
> Not cost effective at nearly $10,000! I understand they're very rare, given
> they were only used for a few years in industry and they're clocking on 3/4
> of a century old, but even then, that seems an order of magnitude or two off
>
On 2022-Jan-06, at 4:04 PM, Matt Burke via cctalk wrote:
> On 06/01/2022 12:59, Jonathan Chapman via cctalk wrote:
>> That said, it's not like replacing them with new will *hurt* -- it just
>> might not fix the whine.
>
> I suspect that it won't fix the problem. Slightly hijacking the thread
> he
On 2022-Jan-26, at 3:41 PM, Rob Jarratt via cctalk wrote:
> I am trying to test a couple of H745 regulators with a DC bench PSU and I am
> having some problems with testing them.
>
> My bench PSU is a twin unit so I can supply the +15V required as well as the
> "AC" input using 20VDC from the othe
On 2022-Feb-10, at 9:50 PM, Chuck Guzis via cctalk wrote:
> I've got a piece of gear here with a bad MC858P used as a bus
> driver--terminated in 220/330 ohms at the far end.
>
> Given that old DTL is a hit-or-miss proposition, I'm proposing to
> substitute a 7438 OC buffer. Pinout's the same, a
On 2022-Feb-13, at 9:04 AM, Douglas Taylor via cctalk wrote:
> Stopped fooling with the AXV11 for now. Applied various voltages to the Data
> Translation input and recorded the A/D octal values to get an idea of what
> the calibration of the board is. It looks very linear, +/-10v range.
>
> Us
On 2022-Feb-17, at 2:38 PM, Rob Jarratt wrote:
>> -Original Message-
>> From: Brent Hilpert
>>
>> 20V on a 10 ohm load: current = 2A.
>> 15V, 1.5A.
>>
>> In this regulator design there is no path for more current than that which
>> the
>> load draws, aside from temporary peak currents t
On 2022-Feb-17, at 11:40 PM, Rob Jarratt wrote:
>> -Original Message-
>> From: Brent Hilpert
>> On 2022-Feb-17, at 2:38 PM, Rob Jarratt wrote:
-Original Message-
From: Brent Hilpert
20V on a 10 ohm load: current = 2A.
15V, 1.5A.
In this regulat
On 2022-Feb-24, at 8:29 AM, Clemar Folly via cctalk wrote:
>
> I'm looking for information about Texas Instruments TB-759933 IC.
>
> Does anyone have the datasheet or any other information about this IC?
A search shows this question was posted over here, with a picture:
https://atariag
On 2022-Feb-24, at 11:32 AM, Paul Berger via cctalk wrote:
> On 2022-02-24 14:16, Brent Hilpert via cctalk wrote:
>> On 2022-Feb-24, at 8:29 AM, Clemar Folly via cctalk wrote:
>>> I'm looking for information about Texas Instruments TB-759933 IC.
>>>
>>> Do
Does anyone have or know whether the schematics for the IBM 5110 or 5100 are
available?
And the tightly related question of whether anyone has done ROM (ROS) dumps?
There are some service manuals on bitsavers, they are field-service board-level
manuals, mostly step-by-step problem resolution gui
On 2022-Mar-17, at 5:02 PM, D. Resor via cctalk wrote:
> Was the computer auction in question a 5100 or a 5110?
>
> Presently I see there is a 5110-C for sale
> https://www.ebay.com/itm/294865912729
Yes, that was/is the one. So it has been relisted. It had been listed as a 5100
or 5100-C earlie
On 2022-Mar-17, at 9:09 PM, Guy Sotomayor via cctalk wrote:
> But it has APL (you can tell by the keyboard *and* the BASIC/APL switch).
>
> I can't say if the price is worth it for that...but having the APL ROS and
> the keytops has some value.
Yes, that is the particular interest in this unit
On 2022-Mar-17, at 8:56 PM, D. Resor wrote:
> It looks as if it needs at least a replacement CRT. From one image it
> appears to be phosphor is blown away in the middle screen. The only way I
> know of this happening, is the neck of the CRT, or the evacuation nipple has
> been cracked/broken.
Tha
On 2022-Mar-18, at 1:31 AM, Christian Corti via cctalk wrote:
> On Thu, 17 Mar 2022, Brent Hilpert wrote:
>> Does anyone have or know whether the schematics for the IBM 5110 or 5100 are
>> available?
>
> No, there are no schematics, only block diagrams. I had created the
> schematics for the Asy
On 2022-Mar-28, at 4:07 PM, Noel Chiappa via cctalk wrote:
>> I don't think the CPU is working at all. The reason being that there is
>> absolutely no LED activity. Including an LED that is supposed to indicate
>> a clock.
>
> Looking at the KDF11-U prints, I finally found that LED (it's pretty lo
On 2022-Mar-31, at 12:36 AM, Noel Chiappa via cctalk wrote:
>> From: Tony Duell
>
>> A short in FET Q15 on the bias/interface board in the PSU could do it.
>> The gate of that FET is driven from an LM339 comparator the -ve supply
>> of which is -15V.
>
> Ah; I hadn't even looked at the P/S prints
On 2022-Mar-31, at 2:14 PM, Rob Jarratt wrote:
>> Those three comparators in the H777 are looking at a time-delay ramp
>
> Is that a typo? This is the H7140 not the H777.
Groan.
When this thread came up I went looking for the 11/24 schematic. I found the
document I linked earlier for the 11/24
On 2022-Mar-31, at 4:12 PM, Noel Chiappa wrote:
>> From: Brent Hilpert
>
>> So apparently I've been looking at the wrong +5V supply (H777) because
>> the rest of you are indeed looking at a different +5 supply (H7140),
>> both of which are in that same 11/24 pdf document
>
> That's because the H7
On 2022-Mar-31, at 8:05 PM, Anders Nelson via cctech wrote:
> Hey all, found this on eBay:
>
> https://www.ebay.com/itm/Corning-Glass-memory-/125087612899
>
> I can't find any info on it - was it some kind of delay-line or magnetic
> laminate stack?
>
> Interesting!
Very interesting - there w
On 2022-Mar-31, at 11:56 PM, Mark Huffstutter via cctalk wrote:
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Brent
> Hilpert via cctalk
> Sent: Thursday, March 31, 2022 11:53 PM
> To: General Discussion: On-Topic and Off-Topic Post
On 2022-Mar-31, at 8:05 PM, Anders Nelson via cctech wrote:
> Hey all, found this on eBay:
>
> https://www.ebay.com/itm/Corning-Glass-memory-/125087612899
>
> I can't find any info on it - was it some kind of delay-line or magnetic
> laminate stack?
>
> Interesting!
Very interesting - there we
On 2022-Mar-31, at 7:44 PM, Noel Chiappa wrote:
>> From: Brent Hilpert
>> DCLO & ACLO behave as power-on-reset signals to the system.
>
> Minor nit: actually, I think it's DCLO which performs that function in a lot
> of places; see e.g. the latches on pg. K2 (pg. 153 of the PDF) and K7. (INIT,
> u
On 2022-Apr-01, at 5:54 AM, Paul Koning via cctalk wrote:
>> On Apr 1, 2022, at 2:56 AM, Mark Huffstutter via cctalk
>> wrote:
>>
>> https://archive.org/details/TNM_Glass_computer_memories_-_Corning_Electronics_20171206_0185
> ...
> That Corning document is also interesting because of its compar
On 2022-Apr-01, at 10:52 AM, Chuck Guzis via cctalk wrote:
> On 4/1/22 10:27, Paul Koning wrote:
>>
>>> On Apr 1, 2022, at 1:25 PM, Chuck Guzis via cctalk
>>> wrote:
>>>
>>> Wasn't some of this glass delay line memory used in early raster-scanned
>>> computer video displays?
>>
>> I don't know
On 2022-Apr-01, at 6:02 AM, Paul Koning via cctalk wrote:
> When I looked at that ebay listing of "glass memory" it pointed me to another
> item, https://www.ebay.com/itm/265623663142 -- described as "core rope
> memory". Obviously it isn't -- it's conventional core RAM. Interestingly
> enoug
On 2022-Apr-01, at 11:51 AM, Paul Koning wrote:
>> On Apr 1, 2022, at 2:38 PM, Brent Hilpert via cctalk
>> wrote:
>> On 2022-Apr-01, at 6:02 AM, Paul Koning via cctalk wrote:
>>
>>> When I looked at that ebay listing of "glass memory" it pointed me to
On 2022-May-15, at 1:16 AM, Eric Smith via cctalk wrote:
> On Sat, May 14, 2022, 16:09 ben via cctalk wrote:
>> On 2022-05-14 11:50 a.m., Nigel Johnson Ham via cctalk wrote:
>>> AFAIR LS can only drive one unit TTL load.
paul
>> LS is 4 TTL, 4 ma low.
>> Was there a trick of forcing the ou
On 2022-May-15, at 3:53 PM, Eric Smith wrote:
> On Sun, May 15, 2022, 13:03 Brent Hilpert via cctalk
> wrote:
> On 2022-May-15, at 1:16 AM, Eric Smith via cctalk wrote:
> > On Sat, May 14, 2022, 16:09 ben via cctalk wrote:
> >> On 2022-05-14 11:50 a.m., Nigel John
On 2023-Jan-21, at 11:25 AM, Mike Stein via cctalk wrote:
> Finally, some Burroughs memory boards containing what I think are 2102s,
> but I'd have to investigate.
Soldered or socketed?
I'm on the lookout for 16 (or more to have some spares) 2102s to populate an
EconoRAM S100 memory board to go
On 2023-Jan-21, at 10:14 AM, Chris via cctalk wrote:
> And if your lids aren't gold plated, is the lid aluminum or some related
> alloy?
Tin-plate on copper would be likely, easy to solder-seal on. Al would not
solder on easily.
Tin does make a nice plating. Even HP made some lab/computing
On 2023-Apr-22, at 3:53 PM, Peter Coghlan via cctalk wrote:
On 2023-Apr-22, at 1:07 AM, Rob Jarratt via cctalk wrote:
>> This seems to be because I measure a steady 0.6V on pin 6 of the transformer
>> (p4, PSU Sheet 3). I just can't imagine where it might be coming from as the
>> chopper won't b
On 2023-Apr-23, at 8:04 AM, Peter Coghlan via cctalk wrote:
...
> This should result in a current
> of about 45 microamps flowing to ground through those components mentioned.
...
> It ought to be possible to measure the same 0.6V across the diode to confirm
> this is where it is being dropped (a
On 2023-May-01, at 2:25 AM, Peter Coghlan via cctalk wrote:
> It seems a bit odd that a power supply from someone like DEC of that era would
> be designed to depend so critically on the absolute value of a rail used
> for startup purposes.
Further to Peter's point above, the 1988 NatSemi databook
On 2023-May-07, at 1:54 AM, Rob Jarratt via cctalk wrote:
> The comments about the tolerance of the 7812 were right, it doesn’t appear to
> be an issue with the replacement 7812 regulator because when I tried using
> the bench PSU to feed exactly 12V to the circuit from the output of the 7812
>
On 2023-May-08, at 11:24 PM, Rob Jarratt via cctalk wrote:
>
> I am going to read your answer more carefully later. But I wanted to check
> one thing. I measured the base-emitter voltage as negative in both cases, and
> yet the TIP121 appears to be conducting on the bad PSU. Surely that means
>
On 2023-May-08, at 12:27 PM, Peter Coghlan via cctalk wrote:
> However, Brent's calculations show that the current trip value for the -12V
> line is as low as 1.3mA and I can't see any reason to disagree with his
> calculations or his conclusion that this seems very low (except that another
> tiny
On 2023-May-09, at 12:28 AM, Brent Hilpert via cctalk wrote:
> I thought I must be off somewhere by 10^n when first doing the calc. The 51Ω
> is 3 orders of magnitude away from the 0.01Ω on the other outputs, so a
> similar diff could be anticipated on the current sense.
>
>
On 2023-May-09, at 11:08 AM, W2HX via cctalk wrote:
> I see some altairs have a metal escutcheon on the bottom with the stylized
> words "MITS ALTAIR 8800 COMPUTER" whereas others, the front panel is just the
> dark faceplate top to bottom. What is the difference? Would one have been a
> kit and
On 2023-May-11, at 7:41 PM, Cameron Kaiser via cctalk wrote:
> it's actually an artifact of the monitor that the upper 6 were clear.
> Actually,
> the stuck bit is entirely bit 2 (i.e., it goes
>
> 0 1 2 3 4 5 6 7 8 9 a b c d e f
> 0 1 2 3 0 1 2 3 8 9 a b 8 9 a b
>
> and the high nybble is OK).
> On 4/22/2023 6:14 PM, Jay Jaeger wrote:
>> I have an HP 2875B paper tape drive that I want to interface to. It has a
>> 50 pin block connector (using well under 1/2 the pins). The connector
>> manufacturer was Continental.
>> I have already discovered, the hard way, that it is not a wincheste
On 2023-May-25, at 1:43 PM, Rob Jarratt via cctalk wrote:
>
> This evening I went to check Vstart for any oscillation. However, all of a
> sudden, the current draw is down to 85mA and PWM has started working. I am at
> a loss to explain it. I wondered if there might be a dry joint, but I have
>
On 2017-Mar-24, at 11:06 AM, Paul Koning via cctalk wrote:
> Which makes sense; DIP packages (independent of material) are designed to a
> small set of standard dimensions. 0.1 inch lead pitch, pin spacing 0.300 or
> 0.400 or 0.600 or similar round numbers.
One (perhaps the singular) exceptio
On 2017-Mar-28, at 2:08 PM, Andrew K. Bressen via cctalk wrote:
> I have about four or five hundred things I'm ready to stop owning.
> I'm in Boston. If anyone wants a number of objects, I could deliver
> to VCF East this weekend.
>
> Inventory list at:
> http://threefingered.com/2017_inventory_
On 2017-Mar-30, at 1:13 PM, Noel Chiappa via cctalk wrote:
>> From: Allison
>
>> FYI this is the same problem designers hit with DRAMS back 40 years ago.
>
> This didn't ring (pun not intended) a bell for me; can you say a bit more?
>
>> From: Chuck Guzis
>
>> I'll offer a suggestion that if yo
On 2017-Apr-13, at 1:24 PM, Chuck Guzis via cctalk wrote:
> On 04/13/2017 12:30 PM, Rich Alderson via cctalk wrote:
>> From: allison Sent: Wednesday, April 12, 2017 3:18 PM
>>
>>> BASIC, why is that the most universal language implemented on
>>> nearly every micro and many other systems.
>>
>> Be
>> 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
On 2017-May-09, at 9:06 AM, Chuck Guzis via cctalk wrote:
> Looking at this documents:
>
> http://www.samhallas.co.uk/repository/telegraph/data_set_101c.pdf
>
> I sill can't figure out what a lot of the stuff inside is for.
I've looked at one of these modems in the bottom of a 33 although not e
On 2017-May-11, at 5:56 PM, Cory Heisterkamp via cctalk wrote:
> Can anyone ID what this panel is from? I picked it up recently for parts but
> the more I study it the more I suspect it may have been part of a computer
> system. At least one status light references 'No Write Ring'. The displays a
On 2017-May-12, at 10:17 AM, Shoppa, Tim via cctalk wrote:
> Cory asks:
>> http://www.radar58.com/panel/
>
> I had always thought Transistor Electronics Corporation had something to do
> with CDC (both in Minneapolis) but CHM tells me I was wrong: it was a
> spin-off from Univac:
> http://www.c
> On 6/4/17 5:44 PM, Michael Thompson via cctalk wrote:
>> I am trying to LTSpice simulate a DEC H-724 power supply from a PDP-12. It
>> includes a Motorola SDA7 dual transistor. I can find any information on
>> this part. Anyone have any info?
On 2017-Jun-05, at 12:38 PM, Al Kossow via cctalk wr
On 2017-Jun-07, at 7:12 AM, william degnan via cctalk wrote:
> Where there any computers that used a "rectangular sense" core RAM?
> Whirlwind core is diagonal. This page describes the differences/evolution
> of the sense line.
>
> More: http://ed-thelen.org/comp-hist/Byte/76jul.html
>
> Were r
On 2017-Jun-13, at 2:26 PM, Eric Smith via cctalk wrote:
> On Tue, Jun 13, 2017 at 12:39 AM, Chuck Guzis via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> The trimpot on the board says to me that the clock is most likely a
>> simple RC affair.
>
> That does seem likely.
There's a 7493 (4-bit cou
On 2017-Jun-14, at 7:44 AM, Noel Chiappa via cctalk wrote:
>> From: Brent Hilpert
>
>>> The trimpot on the board says to me that the clock is most likely a
>>> simple RC affair.
>
>> There's a 7493 (4-bit counter) on the board as well, which looks to
>> have connections to the dip switches beside
On 2017-Jun-14, at 11:33 AM, Noel Chiappa via cctalk wrote:
>> From: Brent Hilpert
>
>> I don't expect anyone was making boards like this expecting to get the
>> target timing from fixed/off-the-shelf component values
>
> Right, that comment was more directed to the discussion here about baud rat
> 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 iden
On 2017-Jul-19, at 3:10 PM, Eric Smith via cctalk wrote:
> I'm interested in the history of the logic design for the edge-triggered D
> flip-flop, as used in the SN7474. The design is composed of three set-reset
> latches (six NAND gates total) per flip-flop.
>
> Does anyone know what year the SN7
On 2017-Jul-19, at 4:22 AM, Christian Corti via cctalk wrote:
> 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 Stan
On 2017-Jul-19, at 5:01 PM, Al Kossow via cctalk wrote:
> On 7/19/17 4:40 PM, Brent Hilpert via cctalk wrote:
>
>> There are near-type cross-refs in the 69 book to the National DM8510,
>> Sprague NE8828, Sprague USN7474, and Signetics N7474.
>>
>> I can ta
On 2017-Jul-19, at 11:37 PM, Rob Jarratt via cctalk wrote:
>> -Original Message-
>> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
>> via cctalk
>> Sent: 20 July 2017 03:34
>> To: Fred Cisin via cctalk
>> Subject: Re: Removing Pitting and Rust From an Enclosur
On 2017-Aug-07, at 3:43 PM, James Hamilton via cctech wrote:
> Hello all,
>
> Is there any good advice on avoiding shorts while testing a male DIN plug
> with a multimeter? I'm trying to test my C64 power supply, but I'm very
> nervous about accidentally shorting it in the process.
>
a few opti
On 2017-Aug-19, at 12:10 PM, Dominique Carlier via cctalk wrote:
> Maybe it's better to give us all the useful information these power supplies,
> moreover it might be useful to other people with the same computer.
>
> An overall bloc diagram of the D-116 power supply including G1 and G2.
> http:
On 2017-Aug-20, at 12:08 AM, Brent Hilpert via cctalk wrote:
> On 2017-Aug, at 12:10 PM, Dominique Carlier via cctalk wrote:
>>>
>>> Question: a faulty voltage regulator can behave in this way? I always
>>> thought it worked or it did not work, but not between th
On 2017-Aug-20, at 4:45 AM, Adrian Graham via cctalk wrote:
> I think I’ve mentioned this PSU before but the question I have might be
> applicable to other cheap switchers. This lump for the original Atari 520ST
> is run by an NE5561N control chip with a D45H1 switching transistor. It’s
> suppli
On 2017-Aug-21, at 8:46 AM, Dominique Carlier via cctalk wrote:
>> As is typical for power supplies of this type and era, this power supply
>> includes current limiting circuitry.
>>
>> The current-limiting circuitry will throttle down the output voltage (not
>> shut it off completely) as the
On 2017-Aug-23, at 6:17 AM, Dominique Carlier via cctalk wrote:
> Here is the situation.
>
> The + 5V 12A that collapses comes out from pins 10-14 / 36-40, the other + 5V
> 12A (pins 15-22 / 36-40) never goes down.
>
> All that I surrounded in green on that image (1950×2361, zoomable) are the
>
On 2017-Aug-23, at 9:55 PM, Lyle Bickley via cctalk wrote:
> On Wed, 23 Aug 2017 21:45:12 -0700
> Lyndon Nerenberg via cctalk wrote:
>
>>> On Aug 23, 2017, at 9:27 PM, Josh Dersch via cctalk
>>> wrote:
>>>
>>> Well, this is the stupidest thing I've read today.
>>
>> "Do Not Feed The Troll" s
On 2017-Aug-25, at 3:23 AM, Dominique Carlier wrote:
> Thank you Marc, I will follow your advice. Doubts must be removed. I would be
> glad to know that the big (and expensive) capacitors are OK.
>
> In the meantime I have new information. Following the remarks of Brent
> Hilpert I sought to hav
On 2017-Aug-26, at 9:57 AM, Rob Jarratt via cctalk wrote:
> I have replaced several parts in the area of the monitor sense circuit,
> including the comparator and the buffer it is driving, but the comparator
> does not seem to be doing what you would expect. I have reverse engineered
> the circuit
On 2017-Aug-26, at 11:09 PM, Rob Jarratt wrote:
>> You have some of your reasoning reversed regarding comparator behaviour.
>> Comparators are typically: +in > -in --> output transistor off --> output
> TRUE /
>> HIGH with pull-up R.
>
>
> I have double-checked the datasheet
> (http://www.ti.com/
On 2017-Sep-06, at 11:03 AM, Paul Koning via cctalk wrote:
>> On Sep 6, 2017, at 1:25 PM, Fred Jan Kraan via cctalk
>> wrote:
>>
>> While reading a biography of Claude Shannon, I try to get a picture how
>> computers were seen and used before Information Theory emerged. It might be
>> somethin
On 2017-Sep-12, at 9:47 PM, Eric Smith via cctalk wrote:
> On Mon, Sep 11, 2017 at 7:43 PM, Charles Dickman via cctalk <
> cctalk@classiccmp.org> wrote:
>
>> On Mon, Sep 11, 2017 at 1:15 PM, Shoppa, Tim via cctalk
>> wrote:
>>> He seems to have been the first to mention ARPANET in a popular
>> ho
On 2017-Sep-25, at 12:42 AM, Adrian Graham via cctalk wrote:
> I’ve been troubleshooting another one of “uncle” Clive Sinclair’s offspring
> (though most folk don’t know his involvement), the Grundy Newbrain. It’s a
> typical early 80s micro with Z80 and 32K RAM made up of 16x 4116 DRAM.
>
> Wha
On 2017-Oct-07, at 2:39 PM, Ed via cctalk wrote:
> Good collection start Al!
> What homed you in collecting Hallicrafters?
>
> We have various SW radios at SMECC but I was really touched to get
> hold of a S-40B like I had in my youth. Now to put new power supply
> capacitor
On 2017-Oct-15, at 4:20 PM, Mike Stein via cctalk wrote:
> Can anybody direct me to some interesting HPGL plotter files for a display at
> the upcoming World of Commodore show?
I'm sending (in a separate, direct message with attachment) the semi-famous /
once ubiquitous Space Shuttle plot from
I don't have the stuff to do the disk recovery, but two years ago I got a
telidon image decoder/display working (the original hardware) at request of
someone who had images/data to display.
He had already done a lot of work recovering data and (IIRC) had a software
decoder for later-protocol im
On 2017-Oct-27, at 10:27 AM, Paul Koning via cctalk wrote:
> So it's a question of what you're after. If you want to run the software, or
> teach the machine at the programmer level, SIMH or equivalent is quite
> adequate. If you want to teach FPGA skills, an FPGA behavioral model
> emulation
On 2017-Oct-27, at 11:28 AM, Paul Koning via cctalk wrote:
> It helps to have a machine built with sane design principles. Things like RS
> flops that don't have both inputs active at the same time. And a properly
> clocked architecture. Neither of these properties holds for the CDC 6600...
On 2017-Oct-27, at 8:40 AM, Dave Wade via cctalk wrote:
> I have an Apple II that produces one beep at power on, but my monitor says
> "no video present". A scope on the output shows frame sync but at low
> levels. The odd thing is that ic A9 appears to be a 74S151 not a 74LS151. I
> wouldn't expec
On 2017-Oct-27, at 12:13 PM, Ethan Dicks via cctalk wrote:
> On Fri, Oct 27, 2017 at 11:40 AM, Dave Wade via cctalk
>
>> The odd thing is that ic A9 appears to be a 74S151 not a 74LS151. I
>> wouldn't expect this to work, but I assume it was working at some point in
>> time!
>
> I don't think tha
On 2017-Oct-27, at 12:57 PM, Paul Koning via cctalk wrote:
>> On Oct 27, 2017, at 3:21 PM, Al Kossow via cctalk
>> wrote:
>> On 10/27/17 12:16 PM, Chuck Guzis via cctalk wrote:
>>
>>> I've long had a fantasy about building a core-logic CPU such as the
>>> Univac Solid State.
>>
>> I have been t
On 2017-Nov-05, at 9:14 AM, Rob Jarratt via cctalk wrote:
> I have moved on with the work on the H7826 PSU in the TURBOchannel Extender.
> However I have found that there appears to be no signal at all on the output
> windings of the transformer. I have posted all the details of what I have
> been
On 2017-Nov-10, at 9:35 AM, Dave Wade via cctalk wrote:
>> -Original Message-
>> From: Brian L. Stuart [mailto:blstu...@bellsouth.net]
>> Sent: 10 November 2017 15:45
>> To: General Discussion: On-Topic and Off-Topic Posts
>> ; Dave Wade
>> Subject: Re: Computing Pioneer Dies
>>
>> On Fri
On 2017-Nov-10, at 12:37 PM, Evan Koblentz wrote:
> https://www.theguardian.com/global/2017/nov/08/geoff-tootill-obituary
>>>
>>> I should point out there is a technical error in the Guardian. The Baby was
>>> the first Electronically Stored Program in what today we would call RAM.
>>> ENIAC
On 2017-Nov-14, at 3:20 PM, Jim Brain via cctalk wrote:
> Having picked up one of these little TI Compact Computer-40 (cc40) units over
> the Summer, I thought I'd work on reverse engineering a RAM cartridge for the
> unit.
>
> As shown on this forum:
>
> http://atariage.com/forums/topic/2557
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
On 2017-Nov-23, at 11:34 AM, Adrian Graham via cctalk wrote:
> Hi folks,
>
> A random facebook post made me dig out my model 4P which has never worked as
> long as I’ve owned it, it’s always just sat on a shelf looking cute.
>
> Good old ASTEC PSU problem so I fixed that, reseated all the thank
On 2017-Nov-23, at 5:07 PM, Adrian Graham via cctalk wrote:
>> On 23 Nov 2017, at 21:18, Brent Hilpert via cctalk
>> wrote:
>> ...
>> You might check the contrast control.
>> I can't find the actual schematic for the contrast control connections, but
>
On 2017-Nov-26, at 7:42 AM, Tony Duell via cctalk wrote:
> On Sun, Nov 26, 2017 at 3:02 PM, Adrian Graham via cctalk
> wrote:
>
>>> What happens if C101 is removed? Also try running it with TR101
>>> removed (or at least the emitter lead of that transistor disconnected).
>>
>> Nothing happens, i
On 2017-Nov-26, at 2:38 PM, Fred Cisin via cctalk wrote:
> On Sun, 26 Nov 2017, couryho...@aol.com wrote:
>> does the 71 sate seem early?
>
> No, a 1971 date does not seem too early.
>
> The price seems steep, even for a "relatively" early modem.
>
> Bell 103 (300bps) dates from 1962.
> The Bell
On 2017-Nov-27, at 5:25 PM, steve shumaker via cctalk wrote:
> On 11/27/2017 2:26 PM, Fred Cisin via cctalk wrote:
>>>> The Livermore Data Systems modems that I sold off were from about 1964?
>>
>> On Mon, 27 Nov 2017, Brent Hilpert via cctalk wrote:
>>> W
On 2017-Nov-28, at 2:54 PM, Fred Cisin via cctalk wrote:
> On Tue, 28 Nov 2017, Brent Hilpert via cctalk wrote:
>> I couldn't find the ebay listing for the NCR modem for some reason, either
>> using the number or by searching by keywords.
>
> https://www.ebay.com/itm
On 2017-Dec-01, at 7:12 AM, Tony Aiuto via cctalk wrote:
> https://www.ebay.com/itm/263005049078
>
> EBay listing for a "Soviet Magnetic Ferrite Core Memory Board". It looks
> like 20 something gigantic cores and a lot of diodes. I am guessing it is
> some kind of ROM, but it doesn't look like a
On 2017-Dec-05, at 9:14 AM, Mattis Lind via cctalk wrote:
>
> Looking more into this document revelas that it covers three boards
> 02640-60009, 02640-60088 and 02640-60112.
>
> Now I had the idea of dumping the character ROM as well. But what is a AMD
> 27S82? I cannot really find a datasheet on
On 2017-Dec-05, at 1:08 PM, Mattis Lind wrote:
> 2017-12-05 20:44 GMT+01:00 Brent Hilpert via cctalk :
> >On 2017-Dec-05, at 9:14 AM, Mattis Lind via cctalk wrote:
>
> >> Does the 27S82 have any equivalents that I could look up instead in the
> >> device list?
>
On 2017-Dec-05, at 1:20 PM, Brent Hilpert via cctalk wrote:
> On 2017-Dec-05, at 1:08 PM, Mattis Lind wrote:
>> 2017-12-05 20:44 GMT+01:00 Brent Hilpert via cctalk :
>>> On 2017-Dec-05, at 9:14 AM, Mattis Lind via cctalk wrote:
>>
>>>> Does the 27S82 have
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 port
On 2017-Dec-14, at 8:58 PM, Gregory McGill via cctalk wrote:
> I recently picked this up from shopgoodwill and it has an older power
> plug. It is NOT a standard plug as shown in the picture below that is too
> tall and pins are smaller etc..
>
> Anyone know the name of this 'standard' so I can f
On 2017-Dec-14, at 10:20 PM, Chuck Guzis via cctalk wrote:
> On 12/14/2017 08:58 PM, Gregory McGill via cctalk wrote:
>> I recently picked this up from shopgoodwill and it has an older power
>> plug. It is NOT a standard plug as shown in the picture below that is too
>> tall and pins are smaller
On 2017-Dec-17, at 3:23 AM, Rob Jarratt via cctalk wrote:
> I have a suspicion that this component may be faulty on the input side of my
> H7826 PSU. A little tester I have does not recognise it, it is possible that
> the currents it uses are too low for this particular triac, but I am not
> sure.
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