test-drb

test-drb@ccmp.vtda.org

101090 discussions

by alsilisk＠icloud.com

Thank you all for your responses and the leads you have given,??Responses to some of your questions and some more questions:?"Have you checked/measured whether they're actually faulty?"?Yes I have, in the picture I have provided on the bottom there are the ends of 3 transistor leads. This was one that fell off as I removed the card and by far the worst corroded, so despite the fact that the rest still work. I need to replace this one.?"?I would suspect that these transistors are pre-drivers for the power transistors and may not be super critical to get an exact replacement."?Would an NPN or PNP with the same HFE suffice, or do I need to know more? Forgive me but I am a complete idiot when it comes to this kind of circuit design and their tolerances.?"Did you get manuals with the printer?? If so it should have ALDs (schematics)."Unfortunately not, and nor can I find any online.?"The 3286 printers and 3277 terminals where infamous for intermittent problems"Excellent, glad I bought something that will provide the true IBM experience.?Thank you,?Al?

4 years, 1 month

IBM transistor replacements

by w9gb＠icloud.com

Al - The Texas Instruments (TI) 139 is likely a 2N139 PNP (BJT) transistor, capable of high speed switching (in that era). The 2N139 was originally an RCA transistor (tall cylinder) found in RCA and GE transistor radios (455 kHz IF section). The TI versions were low profile metal case, TO-33 case (8.5 to 9.5mm diameter) greg == From: Al <alsilisk at icloud.com> To: cctalk at classiccmp.org Subject: IBM transistor replacements Dear all, A while ago I received an IBM 3286 printer, annoyingly some of the transistors in the printer section have been corroded. What I am having trouble with is reading the part codes and finding a modern equivalent of them. One has a Ti logo and two sets of numbers (attached). Does anybody know which numbers are the part numbers and if they are IBM house numbered? Photos of the Ti transistors and card assembly: https://drive.google.com/drive/folders/1JTnsWS4A8NrYJNFsqK2ejOeqqJNjoF1w?us… Thanks in advance, Al

4 years, 1 month

Micro Technology Board Info

by g-wright＠att.net

Have this board here, but can't find any Info on it. Says Neptune board on the silkscreen, tag say model MSD138 T devDates are about 1990 to 1992. https://www.dropbox.com/s/uu8x7bc5a08jw90/IMG_2200.jpg?dl=0 https://www.dropbox.com/s/e8z542sdnusjpqa/IMG_2201.jpg?dl=0 https://www.dropbox.com/s/xql6w5zhiismbel/IMG_2199.jpg?dl=0 - Jerry

4 years, 1 month

IBM transistor replacements

by alsilisk＠icloud.com

Dear all, A while ago I received an IBM 3286 printer, annoyingly some of the transistors in the printer section have been corroded. What I am having trouble with is reading the part codes and finding a modern equivalent of them. There are two types. One has a Ti logo and two sets of numbers (attached). Does anybody know which numbers are the part numbers and if they are IBM house numbered? Photos of the Ti transistors and card assembly: https://drive.google.com/drive/folders/1JTnsWS4A8NrYJNFsqK2ejOeqqJNjoF1w?us… The other is an IBM transistor with what appears to be a 3 digit part code; for which I have been pointed to a list of house numbering and equivalents on the 1401 website. I was told the list is much older and I fear it might be out of date. However there is an entry for the part codes on my IBM transistors. Should I trust the list for replacements? http://ibm-1401.info/BobEricksonIBM-Transistor-Substitution.html Thanks in advance, Al

4 years, 1 month

K12MIT on PDP-12

by cc＠informatik.uni-stuttgart.de

So, with the help of you here, I was able to create OS/8 LINCtapes and to run SerialDisk. Everything runs very fine. Now comes the next thing: I want to have K12MIT, and it is no problem to compile or load the program. *But*: When I start K12MIT I don't get the prompt. I see the welcome message, and it correctly identifies the machine as a PDP-12, but that's it. As I've found out it apparently overwrites its code, the processor is looping around address 3600-3620. Examining the memory reveals that the code at 3600 has been overwritten with junk. So it's clear that it won't run anymore. What happens? Was anyone else able to run K12MIT on a PDP-12? BTW the same binary runs fine on a PDP-8, be it a real machine or SIMH. Christian

4 years, 1 month

Jim Warren has passed away

by cliendo＠gmail.com

https://web.stanford.edu/~allison/JimWarren.html For those who do not know about Jim Warren Jim Warren's wiki page https://en.m.wikipedia.org/wiki/Jim_Warren_(computer_specialist)

4 years, 1 month

The precarious state of classic software and hardware preservation

by mjkerpan＠kerpan.com

The recent discussion of the sudden disappearance of DtCyber and the various classic CDC software to run on it from the Internet has got me thinking about just how precarious so much of computer history is in. So much of what's out there online (and in person) today is at risk just vanishing if whoever maintains the archive either loses interest (lots of projects over the years succumb to this) , or rage quits (see the expungement of DtCyber and Controlfreaks from the internet), or ends up dying without having made proper arrangements (See the sad fate of the Living Computer Museum, which was killed by its new owners as soon as COVID gave them an excuse to do so) What are we, as a community, to do to fix this and make sure that our history stays peserved and isn't one bad day away from vanishing. Mike

4 years, 1 month

Extra books

by cctalk＠gtaylor.tnetconsulting.net

Hi, I find myself with some extra books (acquired as part of an auction) that I don't have any interest in keeping. As such, they are available to move to a home that will appreciate them more than mine will. - CBASIC Simplified - Jeffrey R. Weber - 0-938862-10-3 - Mastering CP/M - Alan R. Miller - 0-89588-068-7 - Osborne CP/M User Guide Second Edition - Thom Hogan - 0-931988-82-9 - The Programmer's CP/M Handbook - Andy Johnson-Laird - 0-88134-103-7 - Understanding Pascal - George Ledin Jr. - 0-88248-149-1 - Turbo Pascal Reference Manual from Borland - Pascal With Style - Henry F. Ledgard / John F. Hueras / Paul A. Nagin - 0-8104-5124-7 - Pascal User Manual and Report Second Edition - Kathleen Jensen / Miklaus Wirth - 0-387-90144-2 / 3-540-90144-2 - Invitation to Pascal - Hary Katzan Jr. - 089433-103-5 - Oh! Pascal! - Doug Cooper / Michael Clancy - 0-393-95205-3 - Pascal Programs for Scientists and Engineers - Alan R. Miller - 0-89588-058-X - Mastering Turbo Pascal 5.5 Third Edition - Tom Swan - 0-672-48450-1 I'm mostly asking for postage and handling for book(s). If you want to tip your waiter, that's appreciated too. -- Grant. . . . unix || die

4 years, 1 month

For Sale, Seattle area: Data General MV/7800 + drives, docs

by derschjo＠gmail.com

Hi all -- I'm doing a bit of cleanup to free up some space and I'd like to try to find a new home for my MV/7800. It's a really cool system that I just haven't had time to spend a lot of time with, and unfortunately it seems unlikely I will anytime soon. The power supply in the CPU has been repaired. There are two large 5236 drives (I believe they have 14" platters, and they weigh about 150lbs apiece) as well, unfortunately I do not have the cabling for them but I don't think it'll be too hard to recreate it. The system appears to be complete with CPU, memory, and disk/tape controllers but apart from getting the power supply going I haven't done anything else to restore it. If anyone's interested, drop me a line. I'd much prefer local pickup but I could be convinced to put this stuff on a pallet if you want to arrange freighting. Thanks, Josh

4 years, 1 month

The precarious state of classic software and hardware preservation

by commodorejohn＠gmail.com

> On 2021-11-21 9:45 a.m., Adam Thornton via cctalk wrote: >> On 11/19/21 9:33 PM, Steve Malikoff via cctalk wrote: >> >> And what happens when you wake up one morning to find archive.org is >> gone, too? >> >> > Fundamentally, eventually we're all going to be indistinguishable > mass-components inside the supermassive black hole that used to be the > Milky Way and Andromeda galaxies anyway. > > Smoke 'em while you got 'em. Yeah, I had a long, hard think about this while the Caldor Fire was looking like it was about to come knocking on my doorstep this fall and I was trying to prep myself for a short-notice evacuation and decide what I could and couldn't take (read: leave stowed in the trunk of the car for the next couple weeks.) Ultimately, while I'd *like* what I have and enjoy to pass on to someone else once I get busy decomposing, in the long run it's all dust, so I'm not gonna worry myself too much over it.

4 years, 1 month

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