test-drb January 2022

test-drb@ccmp.vtda.org

118 participants
85 discussions

by mark.kahrs＠gmail.com

Has anyone ever used Amazon Mechanical Turk to employ typists to type in old listings of lost code? Asking for a friend.

4 years

mystery S-100 available

by sieler＠allegro.com

Hi, I have a mystery S-100 computer that I'm would like to sell, from the estate of the late Ken Gielow (author of Z80DIS, a great Z80 disassembler). The proceeds will be donated to a non-tax-deductible magic group Ken was a long-time member of. The computer is located in Cupertino, CA (aka "the heart of Silicon Valley", in the S.F. Bay Area). (If reopened, you can combine a pickup with a visit to the Computer History Museum in nearby Mountain View, CA! :) This would likely be quite expensive to ship. I'd guess 30+ pounds. Photos and some info at: www.sieler.com/ken_photos Some of the hardware (also listed on the above page): ThinkerToys buss unknown semi-transparent front panel spare/uninstalled Ithaca Intersystems DPS-1 front panel 10 various boards inside metal case (heavy) There may be manuals on some of the boards and/or the Ithaca, but I'm not sure yet. (They would be included, if they exist.) I wanted to take photos of each board, but having been seated for about 40 years, they don't come out if I tug gently. None have integrated board lifters, unfortunately (I tried a boroscope, but could not get useful photos.) Based on the labels on some EPROMS, there's a chance that it's a homebrew TRS-80 clone, with both Level II BASIC and CBASIC, and may have Morrow DISCUS software on it. We're looking for an offer on either: - the Ithaca Intersystems front panel; - the computer with all the boards or both. Suggestions welcome, thanks!

4 years

Question about DECtape formulation

by jnc＠mercury.lcs.mit.edu

> From: Gary Oliver > Paul - thanks for the bitsavers reference. Ahem! In any case, it's Al who really deserves the credit, for finding that document, and putting it up. Noel

4 years

Typing in lost code

by jnc＠mercury.lcs.mit.edu

> From: Gavin Scott > I think if I had a whole lot of old faded greenbar etc. ... Someone may > even have done this already See: https://walden-family.com/impcode/imp-code.pdf Someone's already done the specialist OCR to deal with faded program listings. Noel

4 years

PDP-8 clone built by Canadian company Consolidated Computer Inc

by rodsmallwood52＠btinternet.com

I am trying to locate documentation on the PDP-8 clone built by Canadian company Consolidated Computer Inc (Mers Kutt) in the mid 1970's. An example exists in the UK and will be restored when more data than just the system can be found. Rod Smallwood - digital equipment corporation 1975-1985

4 years

Compaq Portable brightness knob

by dave＠661.org

Would someone please suggest a replacement for the Compaq Portable's brightness knob? This was missing on mine when I got it. -- David Griffith dave at 661.org A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

4 years

Building a BA08 for a pdp8/L

by cz＠alembic.crystel.com

So now that my pdp8/L is up and running (it now has a serial port and runs FOCAL69 quite well) I'm thinking about the next step, which is of course more memory. This requires a BA08 or BM8/L or something expansion box but to be honest I have enough spare flip chips and such from the wrecked 8/I to build about 3 core memory systems. So given that the schematics for the BA08 are online, they look pretty darn simple, I have the parts, and I have the parts does anyone know if it's possible to get a flip chip backplane to work on and wire up to emulate a BA08? It looks like they just used the data break interface lines to hook up to the processor. Everything's there, Memory address bus, memory data bus, and the various signals for jumps and the like that could allow one to decode and implement the extra instructions needed. Hm. Might just be easier to build it with an FPGA or something as it's mostly linking up simple gates and the whole core memory section could be removed by a 4k*12 memory array. Anyone ever done this? C

4 years

VAX 780 on eBay

by jnc＠mercury.lcs.mit.edu

> This: > https://www.ebay.com/itm/275084268137 > ... > Anyway I fully expect it to go ... for a _lot_ more than the opening price. Much to my surprise, it didn't sell at all (although a number of other lots, likely from this machine, did.) I'm rather puzzled that an -11/70 will sell for north of $10K, while a /780 can't fetch $5K. I can only guess that PDP-11'S are seen as more important in the collector world (even though the BSD work, which had such a huge impact on UNIX, which has now - in the form of Linux - taken over the world, was centered on the VAX). Noel

4 years

WARNING: Clear QIC Tape Bands

by lists＠glitchwrks.com

https://i.imgur.com/48EfOQG.jpg That's after sitting parked a couple months. I have a Dysan doing it too. The Dysan had been re-banded with a boiled 3M band and run for years like that with no shedding. I have another Dysan with a green Plastiband in it which is also fine, minimal/no shed. So, I think we may need to re-evaluate if the clear Amazon cheap "plastibands" are perhaps totally incompatible with tape. I know, I know..."just use the band to get data off." But I want to *run* QICs without having to destroy them constantly. Thanks, Jonathan

4 years

Source for replacement caps in H744 regulators

by robert.jarratt＠ntlworld.com

I think I may need to replace the two output capacitors in some of my H744 regulators. These are screw terminal 6,000uF 10V parts. I have looked on Mouser, Farnell and Digikey and there don't seem to be any available, and any that are listed are really rather costly. Does anyone know where I might find some, preferably from a reputable supplier. Note that I am in the UK. If I can't find 10V rated ones, then, generally up to what sort of voltage rating can I go? Of course, physical size will be a factor, but electrically can it affect operation of the regulator if the rated voltage is too high? Thanks Rob

4 years

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test-drb January 2022