So I'm currently in the process of restoring this lovely donated machine (thanks Jon, and thanks Terry for passing on his message), and wanted to make a thread on my progress. There will be video footage coming, because as I work on it, I'm leaving my camera recording continuously.
The machine was originally a 128KB RAM unit with twin floppy drives and a monochrome CGA display.
Later in life it's had a couple of upgrades, namely a 512KB RAM card and a 30Mb 3.5" Miniscribe hard drive unit.
It is complete including monitor and keyboard and in much better condition than I expected (visually).
Had not had power applied for approximately ten years.
Some interesting things about the machine I discovered:
- very very easy to work on, the engineers did a great job of making this machine servicable, screws are easily accessible, easy to find, and there isn't a huge number of them.
- real time clock standard as part of the display adaptor
- no power supply cables to the motherboard, it's done using a block of pins which slide in to the PCB of the power supply when installed.
- you can access the inside of the PSU without removing it from the case, two screws then slide the cover off
- PSU and floppy drive are both from Qume
- BIOS dated 1983, display adaptor dated 1985
- Intel 8088 with AMD support chips
- video card has a COM1/2 jumper, and a UART but no COM port attachment
- PSU has an output on the back which I beleive is to tell the monitor to turn on
- PSU is 200W and has a 24V fan
- motherboard takes up the entire base of the case but is very well spaced and easily laid out
I removed the power supply from the machine and removed large amounts of rust dust with a toothbrush, quite a few diodes with corrosion but still appeared connected - all capacitors visually appeared healthy.
Using a hard drive as a dummy load I applied power and nothing happened. Since many of these power supplies need a motherboard attached to turn on, and the connectors were non-standard, I tried it on the original motherboard. Nothing happened again. I checked the fuse and it was fine. I tested the +12V rail and found off I had 0V but on I had 0.04V (peak of 0.07 for a second).
With these voltages, I made a quick standalone video of the multimeter readings, when the 2 amp fuse went bang and I jumped like a little girl. A peak of around 1V (from memory) showed up on the multimeter.
No components were damaged. I'm going to do some investigating, and possibly send the power supply by itself to an electronics repair guy who has done work for me before. I think the fault is actually in the transformer units, the plastic covering which holds them together seems to have perished allowing the coils to move away.
A 30Mb Miniscribe 3.5" in a 5.25" bracket. Would not spin up.
You'd apply power and after ten seconds just get error codes flashing at you. The error codes said to me the logic board was likely OK. I put my ear to it and could hear a hum before the light flashes - I suspected this was the motor engaging but it was unable to spin the platters. I removed the top drive cover, and found the platters to be stuck. With a little careful encouragement I was able to free them up. I applied power and she whirred up to speed, but still gave error codes, a second attempt and no codes. Put the lid back on with just enough torque for the rubber gasket to seal and connected to the 8 bit controller (I'd installed the card/controller in my 386 test machine).
First time, no 1701 from the controller, but then NO ROM BASIC (386SX33 with no EPROM sockets spare, and they still use this meessage), rebooted again with a floppy drive connected and it started chattering away booting DOS. I think the card requires a working floppy drive to be installed (possibly to complete it's A -> C boot sequence).
It is the loudest hard drive I have heard in a long time but it is happy now. It booted MS DOS 5 and started up an old version of Direct Access (the menu system). As usual I had a browse to see what programs were installed - see what the machine was used for - I didn't look at any personal documents. The usual programs like Wordstar,Fastwire and XtreeGold were on there, but the most interesting was MS QuickBASIC (not QBASIC) and source code for a project which appears to be designed to run the scoreboard at Eden Park.
I'm going to contact the owner and see if he wants anything retrieved, but at some stage this hard drive will get a low level format.
Floppy drive is up next, although I suspect after a clean it'll run perfectly. Monitor I can't test until the power supply is repaired.
Wanted - Dead or Alive - Reward $$$: Compaq Deskpro 8088 / 286 / 386 - IBM RT 6150/6151 parts - AT&T 3B2 partsVC Twitter