Wrap-up of System Source Repair Workshop 1/29 & 1/30, 2022
I had a great time at System Source's Repair Workshop this past weekend. Bob Roswell was a very generous and gracious host. I left at 7:30PM on Friday night because the snow was piling up in NJ. I live near InfoAge so the whole area got 12 inches of snow. But west and southwest of my home, got little to none. So the drive to System Source was a breeze with mostly highway. It took about 3 hours. Stayed at a hotel Friday and Saturday night and got a good sleep. When I got there Saturday things were in full swing with the usual suspects from InfoAge repair workshops, plus the usual System Source suspects. So a very good turnout of about 25 or so people. Lots of stuff fixed as I saw. I made some pickups of repaired VCF artifacts and drop-offs to be repaired artifacts. I loved looking at what was new and looking in more detail at the exhibits in the museum. I also got to catch up on all my friends there and talk about vintage computer stuff it was great! I also got a chance to play with the Xerox Alto for a few hours and see what worked and what didn't. Very cool and rare opportunity for a rare machine that works! This was my favorite part of the weekend. Maybe others want to chime in on what they were working on. ========================================= Jeff Brace VCF National Board Member Chairman & Vice President Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey@vcfed.org
On Sun, 30 Jan 2022, Jeffrey Brace via vcf-midatlantic wrote:
Maybe others want to chime in on what they were working on.
I was only there on Sunday. My project was to evaluate the two HP 3000 Series 30 systems owned by System Source. One system was an empty cabinet, but the boards and cable were eventually located. I populated the card cage with the requisite boards, and added the necessary cables to connect to the system console and serial terminals, and the HP-IB devices (disc, tape and printer). On power up, only one of the fans turned on, and there were no DC voltages. The boards in the card cage are: Bus Interface Controller CPU Firmware PCA Maintenance Interface GIC (General I/O Channel, HP-IB interface) GIC ADCC Main (Asyncronous Data Communications Channel) Memory Controller 128K Memory Array 128K Memory Array 128K Memory Array 128K Memory Array I switched to the other system, which had some of the boards installed. This system powered up. The +5, +12 and -12 DC voltages were within tolerance, but the +5M, +12M and -12M memory voltages were absent. There are two boards in the memory power supply which are suspects (the fuses are okay). Back to the original system, I found a blown 3A slo-blo fuse. A search for a replacement yielded nothing on hand (or at NAPA Auto Parts). I elected not to swap the good fuse from the second system, since that was the only one we had. If, after obtaining new fuses, the power supply on the first system comes up, we could consider swapping out the memory power supply boards. Substituting a modern power supply is also a possibility. The CE manual lists the the power requirements for the memory supply as: +5M 5.0A +12M 3.5A -12M 0.38A I also checked out the 2621P terminal to be used for the console. It powers on, passes the self-test, displays correctly and types in local mode, and the integral thermal printer is working. The battery which maintains the configuration is dead, and should be replaced with a Mallory TR133 or equivalent. A cable to connect the terminal to the system console must be obtained or built. The cable part number is 13222N (13222-60001). If you're building one, the diagram is on page 22 of the Terminal Cable Handbook: http://www.bitsavers.org/pdf/hp/terminal/5957-9918_terminalCableHbk.pdf A longer cable is part number 92217A. There are currently one of each listed on Ebay. System Source also has two 7970E tape drives (1600 bpi), two 7925 removeable pack disc drives (120MB), two 2631A printers, and a 2608A line printer. All of these can be connected to the HP 3000 system, and will need to be evaluated. There were no disc packs found for the 7925 drives. If they cannot be located, disc emulation via HPDrive would be an option. I had a PC with HPDrive installed in case testing got that far, as well as 9-track tapes to load MPE-V/R. Another ribbon cable is required to connect an ADCC Extend board to the ADCC Main board, to add four more serial ports. The part number is 31265-60002. To make one, you would measure the contact spacing on the upper ADCC frontplane connector and obtain two 50-pin edge card connectors and a short piece of 50-pin ribbon cable. The cable connects the upper frontplane connectors on the ADCC Main to the ADCC Extend board to its right. Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/
On Sun, Jan 30, 2022 at 11:45:33PM -0500, Jeffrey Brace via vcf-midatlantic wrote:
Maybe others want to chime in on what they were working on.
First I tried to read the RD53 from the 11/73 discussed on the list earlier. The drive wasn't spinning up so we lifted the drive electronics board to get at the spindle motor and got it to spin. Remarkably easy to do. Two captive screws to undo one side of the board and it pivots up on some pins at the other end. The MFM reader mostly didn't see anything. One point it seemed to identify proper data for a short time. With a scope it was outputting just very narrow pulses at improper interval. We were going to try to swap the electronics board with a drive I brought but when we pulled a flex cable one of the pins stayed with the connector. Three more pins were about to break. Instead we jumpered the four lines hoping the initial broken pin was the problem. No such luck. We decided that further work was going to be time consuming. May still be possible to recover but not easy. I think he was going to try to get the tapes read and see if that goes better. I moved on to the 8/I. At end of last workshop it would single step short programs toggled in but not run at speed. Much poking and found the memory voltage was collapsing when running. Two regulator cards were bad. Swapped in a spare and one from the PDP-12 and it could run programs. Replaced bad bulbs on front panel and one bad drive transistor. Was able to load diagnostics over the serial port. Instruction test 2A passed. 2B failed with a memory location looking like it was incremented by one. The first 4k of memory passed it diagnostics. Tried to run FOCAL language. Crashed after printing CONGRATULATIONS. More for next visit. Left it with two light pattern programs that can be used to show it does something. Got to play with the front panel on the LINC for a little while. It was showing a reasonable amount of life but looks like its going to need some attention.
participants (3)
-
David Gesswein -
Jeffrey Brace -
Mike Loewen