Ah! You reminded me. A professor of mine at University was an amazing junk collector. He was able to get a number of companies to donate computer equipment to the engineering department. All kinds of obsolete hardware strapped to wooden pallets sat in the basement for years.
I first saw a core memory board from a 70's era Burroughs machine down there. A huge circuit board with a dual stack of four panels of 32x32 cores. It was absolutely beautiful. I used to go down there once or twice a week just to explore. After every summer when I got back for fall semester there was more. If you wanted a challenge or special project assignment they would pull out a board and schematic and tell you to go figure out what the board did and how it worked. "See if you can make it do something." For a senior project, Dr. Shaw and Dr. Eppler pointed me to a new group of pallets. "It's CAD equipment used in the oil and gas industry. See what you can do with it." There were two Varian V77-600s in racks with 1MB RAM cards, the loadable control store option, sync serial cards, and math coprocessor card. Four racks of tape machines. Two racks of 5MB disk pack hard drives (The Gigabyte unit is so common today I have to remind myself that it was actually Megabytes back then). And four of the coolest workstations I've ever seen in my life: The Autotrol CC-80 workstation. I swear they were like something out of the Star Trek Original Series TV show. They had Tektronix storage displays attached to motors that lifted and tilted. Desk panels you could set an E size sheet of paper on. They were amazing. CAD operators must have been treated like royalty back then. None of this 64 sqft corporate cubical crap. (You got 64 feet? I had to make do with 36. Ha! That's nothing. My first desk was stuck on the wall next to the water fountain between the mens room and the entrance to the data center.) That last one wasn't a joke, actually :) I spent a semester and a half re-assembling the system on the second floor after electricians had installed enough power for the racks. It wasn't too hard figuring it out because we had complete documentation and everything was labeled when it was disassembled. There was a huge book on the Vortex Real Time Executive. And a ton of books on the AutoTrol CAD software. There was a huge flat bed plotter that wouldn't fit in the elevator so I had to leave it in the basement untouched. I was able to get one of the systems to boot and AutoTrol running. But when I called the company we got the hardware from to ask some questions, I was told that we weren't supposed to be able to run the software. They donated the hardware but software was not part of the deal and shouldn't have been sent to us. But there it was. Boxes of tapes and disk packs all nicely labeled. The licensing issue and graduation ended the project for me but I have never forgotten those V77 CPU boards and the CC-80 workstation. All 7400 logic I believe they were with these cool bubble LED displays for troubleshooting. The CC-80 had this really neat little card cage of boards for keyboard, digitizer, and CRT control. The whole system was amazing to look at compared to the AutoCAD and DEC Alpha based CAM systems I was trained on after graduating. The DEC color displays were great but that green Tek display was like science fiction come true. I still appreciate how beautiful computers were in the 60s and 70s when everything was racks, card cages, and painted steel enclosures that could last for decades. Like you said, fun times. Jerry On Sat, Jul 10, 2021, 6:55 PM Peter Noeth <[email protected]> wrote: > I have always used ML / BASIC programs I wrote to do troubleshooting / > burn-in testing, using loopback connectors to test external ports (on a par > with the original IBM XT Diagnostics diskette). The programs could be > simple or complex, depending on the situation. Sometimes I only burn-in > test the area of repair. For example the serial port, with a loopback > connector. If the problem was in the address decode circuitry, then I test > all devices (memory, display, RS-232, printer, etc). If the repair required > replacement of an IC or module, then I usually test for only one or two > hours. If the problem is intermittent connections, then I test for 24 to 48 > hours, at elevated temperature. > > Of course if the uProcessor is not running, then the computer cannot be > used to diagnose itself. In that case, if the uProcessor has a pin that can > "tri-state" all output pins (the 80C85 does), then I used a test computer > with a parallel port interface I designed that could exercise all the > address, data and control pins by clipping onto the target computers > uProcessor with a cable and test clip. The test program could also write > and read from Memory / Port addresses to check the address decoding > circuitry on the target computer. > > But that was decades ago now. I should re-make that interface board again > for nostalgia sake. Back in those days, I frequently used my M100 as a test > computer where I was working (CALMA, a CAD/CAM equipment manufacturer), > repairing Data General mini computers, and Lexidata graphics computers > mostly along with the peripherals. Discrete ALU based processor boards with > ~150 74LS type IC's, core and dynamic memory, 9-track tape, video monitors, > serial data terminals, etc. > > Fun times. > > Regards, > > Peter > > >> ------------------------------ >> >> Message: 6 >> Date: Fri, 9 Jul 2021 19:58:12 -0500 >> From: "Jeffrey Birt" <[email protected]> >> To: <[email protected]> >> Subject: [M100] Burn in program >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset="us-ascii" >> >> Hi all, >> >> Burn in test? I was just wondering what sort of program you guys like to >> run >> as a burn in test of a computer you have just repaired. I modified the >> M100 >> test harness code so can run a continuous RAM test but that is not a >> really >> useful test that everyone can use as it only works with the test harness. >> >> Maybe something in BASIC that just runs some calculations, displays things >> on the LCD, etc. to test how stable the computer is when running for a few >> hours. Any favorites? >> >> Thanks, >> >> Jeff Birt >> >>
