test-drb January 2022

test-drb@ccmp.vtda.org

118 participants
85 discussions

by robert.jarratt＠ntlworld.com

I am going to be moving on to testing some H745 regulators. If I understand the schematic correctly the +15V input is the reference voltage used to regulate the -15V output, is that correct? If so, then presumably it doesn't need a whole lot of current, is that right? Thanks Rob

2 years, 3 months

Retro Chip Tester Pro, US shopping basket?

by wh.sudbrink＠verizon.net

In response to my wife's "Buy yourself a Christmas present" direction, I've ordered a Retro Chip Tested Pro board. When you purchase the board, you get a BOM and links to stored shopping baskets for some European vendors. Has anyone built this in the US and stored their basket with a US vendor? Rev 1.2k by the way, but any basket would be helpful as the BOM differences between the versions are listed. Thanks, Bill S. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 years, 3 months

Question about SIMH Sigma-7/9 emulation

by dfnr2＠yahoo.com

Hi all, I see that SIMH incorporates the 32-bit Xerox Sigma architectures.? The Sigma 8/9/5x0 architectures are commented out but compile fine? Does anyone know if those later architectures have known issues? Has anyone succeeded in running CP-V on those emulations?? It would be amazing to run CP-V and tha various languages on a Sigma 9 emulations, not to mention the 350-point and 550-point adventures.? However, I haven't found any type of software on line.? Does anyone know of a stash somewhere? I remember that the Living Computer Museum, when it was open, briefly had a Sigma 9 up and running with CP-V, but was restricting public accounts due to some issue with the account generation mechanism.? I wonder if someone associated with the Museum might potentially have access to some CP-V tapes or images, even if the museum is closed. Thanks in advance, Dave

2 years, 3 months

NEXT/LISP Mirror has viruses

by billdegnan＠gmail.com

http://mirror.informatimago.com/ This site has or had viruses at some point, the tigger files.html files are still present. be cautious, and let the person who runs it know if they're known. BIll

2 years, 3 months

mirror of ftp://unix.hensa.ac.uk

by spectre＠floodgap.com

Looking for some tools (guide_reader, others) that were apparently only on unix.hensa.ac.uk's FTP. This hostname still exists, but directs to University of Kent's mirror service, and there is no trace of the old archive. Anybody happen to have saved any pieces of it? -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- In memory of Peter Graves --------------------------------------------------

2 years, 3 months

IBM Model C typewriter

by van.snyder＠sbcglobal.net

I have an old IBM Model C typewriter. I can't bear to throw it away, even though it doesn't work well. The carriage doesn't advance, and the A key doesn't work. Do you know how to tune it up? If you want it, it's yours for the price of shipping. I'll probably take it to UPS and ask them to pack it. It will fit in a 24" x 18" x 12" box. Gross shipped weight about 40 lbs. Local pickup free. La Crescenta, CA

2 years, 3 months

PDP-11/34 FP11-A on eBait

by jnc＠mercury.lcs.mit.edu

Speaking of FP11-A's: https://www.ebay.com/itm/275096265379 I wouldn't mind having one, but not for that much! I wonder how much it will go for? Noel

2 years, 3 months

H7821 power supply in MicroVAX 3100, SCSI disk enclosures and others

by cctalk＠beyondthepale.ie

The recent discussion on BSC protocol prompted me to dig out my Microvax 3100 with DSH32 synchronous serial interface. It had been idle in storage for several years and it wouldn't power up, only giving a brief flash on the diagnostic LEDs and a quick twitch of the fans. There was a slight smell, like the stale air that comes out of a deflating tyre. I took out the H7821 power supply and found that five identical brown 1800uF 25V electrolytic capacitors on the output side had leaked. The SCSI disk enclosure where the machine's system disk lives required several power cycles to get it to run at all and it died as soon as the disk tried to spin up. It turned out to also contain a H7821 power supply which had a similar issue with the same five brown capacitors, although not as extensive as in the main unit. I found a second disk enclosure which had seen little use and grabbed the power supply out of that to put in the MicroVAX. It worked well enough to test with but there was a ring of goo around the bottom of one of the brown capacitors which was worst affected in the other units. Time to order a batch of replacement capacitors and figure out what else has been damaged. While it is not the worst I have seen, access to these power supplies for repairs is quite difficult and it is really difficult to debug them safely while they are running with the cover off :-( If anyone has anything with H7821 power supplies in them, I suggest checking on these capacitors. If anything with these power supplies is in storage, I suggest ensuring it is stored the normal way up as this should limit the ability of the goo to escape and spread around the power supply. And there I was thought I was being safe enough by removing the nicad battery packs some years ago... Regards, Peter Coghlan.

2 years, 3 months

The Portable C Compiler (pcc)

by ccth6600＠gmail.com

The original "Portable C Compiler" by S. C. Johnson (also known as "pcc") had functional support for the Data General Nova. Could somebody please point me to this original implementation? There is a modern C99 version of this compiler maintained by Anders Magnusson at: http://pcc.ludd.ltu.se/ Unfortunately in this version the Nova architecture is no longer supported and won't build correctly although associated files are still in the source hierarchy. I am looking for the original implementation - not any recent work. Thanks Tom

2 years, 3 months

8" Floppy Drives needed

by jnc＠mercury.lcs.mit.edu

> On Wed, Jan 12, 2022 at 12:16 PM Mike Katz wrote: > I am looking to make a RX01 (and hopefully RX02) disk formatter Something that can format floppies for the RX01 can effectively format RX02 floppies, too. An RX02 drive can convert RX01-formatted floppies to RX02-formatted floppies. Given how arcane the RX02 format is (sector _headers_ are written in single density; sector _data_ is written in double) I'd be pretty surprised if anything except an RX02 can do it. Noel

2 years, 3 months

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test-drb January 2022