test-drb September 2015

test-drb@ccmp.vtda.org

198 participants
312 discussions

by mokuba＠gmail.com

+1-410-734-6804 New hobby thing. ;) Wildcat! 4 running on it, stock out of box config. If you don't see all the menus except for help and send to sysop, wait till I validate users. When I get back home i'll set it to give non-validated users more permissions, though. -- Gary G. Sparkes Jr. KB3HAG

8 years, 10 months

IBM 026

by misc4email＠yahoo.com

Can anyone help me to locate an old IBM 026 printing keypunch for a project on which I am working?I was an IBM Field Engineer many years ago and I used to service lots of Unit Record equipment at that time.Any help in locating a machine would be greatly appreciated.Thank you. AlEx-IBM Field Engineer

8 years, 10 months

Schematics KDJ11-A / M8192?

by jnc＠mercury.lcs.mit.edu

> From: Holm Tiffe > Anyway, thanks for the schematics Eh, de nada. > I have the board running again. The fix was simple, the xtal was bad. You're lucky it was something so simple! (Although we've seen this kind of thing before - I had that 11/23 with a bad crystal.) I've got three dead 11/73 boards (from someone else), but none of them are that easy. Different symptoms on all three, but I suspect the State Sequencer gate array on all three. On one, at least, the ILOE latch control signal from that gate array is sitting at 2V (which I seem to recall is characteristic of a TTL input that's not being driven). Maybe it's just some corrosion, and re-seating the gate array (if I can work out how to unseat it - don't have the extraction tool) will fix it. Otherwise, I'm SOL. At least the J11 there are spares for - that gate array is surely umobtainium. Noel

8 years, 10 months

BBC Model B with Raspberry Pi Internals

by mark＠wickensonline.co.uk

Bit of a tricky one to google this, so thought I'd consult the list - does anyone know of a documented project that replaced the internals of a BBC Model B with a Raspberry Pi (or MiniITX PC) interfacing with keyboard etc. to bring modern internals with a traditional interface? I don't even know if there is a word for these kind of projects? Thanks, Mark.

8 years, 10 months

A poltergeist in my machine?

by jnc＠mercury.lcs.mit.edu

So I've mentioned how I've seen this wierd behaviour where QBUS memory boards that hadn't been used in a long time didn't work when first plugged in, but started working later. I just had something even weirder happen, and am curious if anyone has an plausible explanations. So I had a dead M8044 (MSV11-D), symptom was that you could write -1 to any location, it read back as 0. Quite repeatable, I can power cycle the machine, take the card in and out, etc, etc. So I throw it on an extender, and start chasing. I have a two instruction loop (write location 0, loop), and I'm watching the data going into the memory chips on the card, and it all looks good. So I add a third instruction (read location 0, after the write), and continue chasing. Data looks good coming out of the chips; then it goes to an octal latch. So I look at the latch enable, and that doesn't look so hot - just a tiny little ugly spike. So I look at the source of that, and it's a D flop. So I look at the D flop's clock input, and it's also a nasty little spike. So that comes >from the output of a triple-AND, and so I start looking at the inputs of the 3-AND. And when I put my 'scope lead on the second input... the memory suddenly starts working! Well, I could see that - the added resistance or capacitance or whatever of the probe might have had some effect on a circuit that was right on the edge. But here's where the ghost enters the machine. I pull the 'scope probe ..... and the memory keeps working! I can power cycle the machine, leave it off for 15 minutes, power it back on - and the memory still works fine! Does anyone have _any_ idea WTF is going on here?!?! I feel like I'm in some sort of AI koan... Noel

8 years, 10 months

21MX proms (per request)

by marc.verdiell＠gmail.com

Thanks for the answers everyone, I am writing everything down... Marc

8 years, 10 months

Control Data ad: Omega 480 "370 compatible alternative" on eBay

by linimon＠lonesome.com

http://www.ebay.com/itm/VINTAGE-197X-RARE-CONTROL-DATA-AD-OMEGA-480-370-COM… Not that I'm going to bid on it, but ... I had never heard of this CDC product before. Does anyone have any idea if this was a real product, or just a way to poke IBM in the eye, or what? mcl

8 years, 10 months

21MX proms (per request)

by jwest＠classiccmp.org

Several people asked, here's the scoop: The common proms for HP 21MX M/E/F are 1K, 4K, and 8K. 1K are used for either loader roms on the cpu board or microcode on the FAB 4K are used for microcode on the FAB or FEM 8K are used for microcode on the FEM The manuals you'll want to print and keep handy: HP 12992 Loader Roms Installation Manual, 12992-90001 (April '86) HP 1000 M/E/F-series Firmware Installation and Reference Manual, 12791-90001 (September, '83) I believe these are both on bitsavers. They are "must have" manuals. These are all bipolar proms, and most modern prom programmers will not be able to program them. I use a Data I/O 29B (with Unipak 2B), and it can program all these parts. Those programmers appear on ebay from time to time at around roughly $400. The blank proms are not terribly easy to find these days. Ebay has them occasionally, but your best bet is sites that cater to arcade machine repair. Here's a non-exhaustive but useful list of compatible parts for each: 1K parts MMI 6301 Harris 7611 Signetics N82S129 National 74S287 TI 24S10 AMD 27S21 Fujitsu 7114 (possibly 7052 as well, need to verify that) 4K parts Signetics N82S141 Harris 7641 MMI 6341 8K parts Signetics N82S181 Harris 7681 MMI 6381

8 years, 10 months

Control Data 160 Ebay

by billdegnan＠gmail.com

Anyone here get the Control Data 160 (Ebay 252070822992)? I must admit time, money, and space aside I would love to have had this one! (I have the manuals at least) -- Bill vintagecomputer.net

8 years, 10 months

'New' PDP-11 prints

by jnc＠mercury.lcs.mit.edu

> There are a number of things like that (e.g. the H786 power supply for > the BA11-N; [print sets] not available separately [online], but in the > 11/23 FMPS [online], if you know to look there): we ought to produce > some sort of registry, to collect such information in one place. So I have started such a registry. http://ana-3.lcs.mit.edu/~jnc/tech/FMPSOnline.html The concept is that eventually search engines will index that page, so people looking for, say, '"BA11-N" prints' will wind up there, and that page will tell them where to go. I went through a number of PDP-11 print sets which are online (11/05S, 11/23, 11/34, etc) to compile the initial list, but it's just a start. I will add others as I come across them; and if any knows of, or finds, any others (i.e. print sets which _are_ online, but do not show up when looked for in common search engines such as Google), please let me know, and I will add them. > I also found prints for the MF11-U, MF11-W, and MM11-Y; none of which > appear to be on-line (although the MF11-U ones might be in the 11/05S print > set, which ISTR is online). On looking at the 11/05S print set online, I think it has most of the MM11-Y prints, but some pages are apparently missing (it claims), so I think not everything is there. > I don't think the ME11-L prints are online either, but those I have in > my 11/05 print set - I'll have to see if that print set is online > somewhere, no point re-scanning them, if so. So it turns out that these don't seem to be online (in any form), but I have a set of hardcopy in my set "PDP-11/05 Engineering Drawings" (which is different from the 05S set which _is_ online), so I will scan them in and make them available at some point (especially since these seem to be the most common PDP-11 core memory boards). If anyone is desperately searching for them, please let me know, and I will accelerate that process. The situation with the ME11-L/MF11-L/MM11-L (which are all the same boards) is slightly complicated. The board set is called an MM11-L (or -LP, depending); G110+G231+H214 for non-parity, G109+G231+H215+M7529 for parity. The MF11-L seems to be a backplane, plus an MM11-L board set; the ME11-L seems to be an MF11-L in a box. Some CPU backplanes (e.g. the older 11/05's) can also take an MM11-L board set. (The _newer_ 11/05's have backplanes which take an MM11-Y - whether an MM11-L would work in them, I have no idea.) Noel

8 years, 10 months

← Newer
1
...
21
22
23
24
25
26
27
...
32
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb September 2015