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101090 discussions

ID UV erasable PROMS used on an IBM PC board?

by organlists1＠sonic.net

This is the CPU board out of a first generation 1982-83 IBM Electronic 85 Typewriter (Electronics Driven Selectric). I was looking to archive the software/firmware from these. The machine was exposed to some dampness. Corrosion has ensued on the interface connector between the CPU and driver boards. The next year, more energy efficient memory ICs were used. Memory power failure back up only consisted of 3 AA batteries and could last up to one year. The predecessor (this board) required 6 AA size Nicads and would only retain memory for a few hours. IBM using their apparently very large stock of OLD aluminum covered ICs in as many products possible I guess. Don Resor -----Original Message----- From: wrcooke at wrcooke.net <wrcooke at wrcooke.net> Sent: Sunday, March 20, 2022 7:13 PM To: D. Resor <organlists1 at sonic.net> Subject: Re: ID UV erasable PROMS used on an IBM PC board? > On 03/20/2022 8:59 PM D. Resor via cctalk <cctalk at classiccmp.org> wrote: > > > 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 More details would help. What is the board? Do you know at what address in the PC memory map they fit? Based on the info you gave and the picture I would bet $1 they are standard 2764 chips. The 2764 was the first standard chip to have 28 pins. The size of the die visible through the quartz window is consistent with 2764 (as opposed to 27128 or 27256) and the fact there is room for 3 which would give 24K total. The PC didn't have a lot of places in the memory map that would allow more than 24K. Three 27128s would be 48K (a LOT in those days) and the 27256 would be 96K. I can't help with the part numbers. But I doubt they are IBM proprietary. The vast majority of chips used in the early PC line were standard from other companies. Will

2 years, 1 month

ID UV erasable PROMS used on an IBM PC board?

by organlists1＠sonic.net

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

2 years, 1 month

restoring a Silent 700 Model 765

by spectre＠floodgap.com

I found my old Model 745 in storage and other than needing a print head clean and adjusting the printer contrast, it works splendidly. It has the manual and I've got some plugs to build it an RS-232 connector when I find some more round tuits. This whetted my appetite for other 700s, including the (in)famous bubble memory 763/765. I was able to land a set of 765 ASRs. One of them came with Telenet transcripts from The Source (various logins from 1978 to 1980), which was really cool reading. I'll scan these. However, neither of them work. Both power on, but they immediately go into COMMAND mode and sit there, which appears to be abnormal behaviour based on what I'm reading in the service manual (thanks, Bitsavers!). The NUM LOCK switch works and the paper advance works, but nothing else appears to elicit a response. One of them advances the page and acts like it's printing the command prompt, but the other one doesn't even do that. The service manual suggests I need to replace both the TMS 9980 and 8080 boards, which would really suck. I'm hopeful that the one that's "more active" has a working 9980 board and I can use the 8080 board from the other one. (I haven't even gotten to the bubble memory yet.) Anyone repaired these units or have an idea of a repair strategy other than replace damn near everything? TELENET 303 8A TERMINAL= @C 301 24 301 24 CONNECTED DIALCOM NETWORK SYSTEM 10 -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- Simplicity is the ultimate sophistication. -- da Vinci ---------------------

2 years, 1 month

restoring a Silent 700 Model 765

by spectre＠floodgap.com

>> 301 24 CONNECTED >> DIALCOM NETWORK SYSTEM 10 >> > Please do scan these! It is hard as hell getting info on The Source > and also on Dialcom! Yes, I definitely plan to transcribe them. There is potentially some copyrighted material here but I think I can just excerpt that and still include all the rest of the login process, etc. Still, would be nice to get the terminal itself working and see what's in the ASR's bubble memory, assuming that's still operational, so any ideas people have would be appreciated. -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- mouse, n: A device for pointing at the xterm in which you want to type. ----

2 years, 1 month

General Data? Computer Equipment Auction - GSA

by mark.kahrs＠gmail.com

The LSSM is very interested in this machine for public display. It would complement the museum's collection of PDP-11s and other 16 bit machines.

2 years, 1 month

LSSM is chasing this, was Re: General Data? Computer

by dave.g4ugm＠gmail.com

I missed a lot of this because g-mail decided to bounce some e-mails. I would like to make a couple of observations:- 1. Many real accredited museums have a smaller percentage of their artifacts on display than private collectors. In the UK both TNMOC and the Science Museum Group have large quantities of hardware that is not displayed. The science museum usually catalogues it but it is not really helpful if you can't see it. 2. All the private collectors I know are very happy to show and demonstrate what they have. It might not be catalogued so well but generally they want to show it off.... Dave G4UGM (Now feeling guilty because what I have is neither catalogued or on display)

2 years, 1 month

IBM 5110 (5100) schematics ?

by bhilpert＠shaw.ca

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 guides, no schematics. As a system, it's small enough to be reverse-engineered, in that regard it's tractable. However, it's implemented using IBM's mid-70s PCB and IC technology, increasing an RE effort by a couple orders of magnitude if not approaching impossible, unless one were to develop some robotic probing system and software. There was a 5110 on ebay, non-working, that a friend had some interest in. It was quite a gamble at the price, in the absence of real tech info. ... Apparently it's been delisted, so my question is just curiousity at this point.

2 years, 1 month

WTD - Oregon/Taumetric M68000 Pascal and Cross Assembler (VAX/VMS)

by classiccmp＠philpem.me.uk

Hi all, Does anyone happen to have a copy of these squirrelled away? - Oregon Pascal M68000 -- cross compiler for VAX (or any other host platform). Probably called "P68.EXE" or something similar. - Oregon / Taumetric M68000 Cross Assembler for VAX (or any other). Probably called "MASM.EXE" or similar. - Oregon / Taumetric M68000 Linker for VAX (or any other). Probably called "MIL.EXE" or similar. The assembler and linker might be ports of Motorola's M68KMASM and M68KLINK -- so something equivalent which takes the Motorola-format .SA files and spits out .RO files should work instead. I've been tasked with getting some ancient code building again, and as usually happens, the "backup" is incomplete... Thanks, -- Phil. philpem at philpem.me.uk https://www.philpem.me.uk/

2 years, 1 month

IBM 5110 (5100)

by organlists1＠sonic.net

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 There were also a 5110 with 8" external drives and a printer which sold: https://www.ebay.com/itm/304377532685 Don Resor

2 years, 1 month

Does anyone/museum test disk packs?

by barythrin＠gmail.com

I was visiting a new thrift store and saw a disk pack they had. I joked that mine are just fun display/conversation pieces. Do the giant drives suffer the same head crash issues that a bad zip disk can do or are these safe if someone actually wanted to see what was on them?

2 years, 1 month

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