The challenge doesn’t officially begin until July 1, but I thought it would be okay to survey what I have, and make a list of things that I will need to do in order to be successful.
As of right now, this is what I know needs to be done:
- Inventory of cards. Identify the S-100 cards I have and acquire documentation on each (jumper settings, schematics, etc)
- Disassemble. Although not too bad, there’s a bit of dust and dirt on the motherboard and power supply that needs to be cleaned up.
- Recondition power supply. The large electrolytics in the power supply need to be reconditioned and tested.
- Test capacitors on boards. Tantalum capacitors of this vintage have a tendency to build up internal whiskers that can cause shorts.
- Logic test. Bring up the system and test for the correct operation of the logic. At this point, all I will have is a small boot PROM on the disk controller. There is a test sequence in the documentation for troubleshooting logic issues at this level.
- Add boot PROM to CPU card. The CPU card has empty pads for a 2708 PROM (with decoding logic and power supply). I need to install this in order to boot to a ROM monitor. From here I will be able to do memory tests, and bootstrap software to be able to write boot disks.
- Burn a 2708. This is turning out to be remarkably harder than I initially thought. The 2708 is an early EPROM that has unique voltage rail requirements for programming and operation. Most modern programmers can’t handle the 2708.
- Acquire some blank DS/DD 10-sector hard sectored floppy disks. This will probably end up being the most difficult part of the whole project. Hard-sectored floppy disks dropped out of favour right around the time of the release of this machine, and haven’t been manufactured for many years.
- Do something useful. Once the machine is up and running, I need to identify a task that I can use the machine for. I do have a Hayes Micromodem 100 card in here, so I may make use of that – however I’m missing the micro coupler which contains the analog interface circuitry to the phone line.
There you have it. Looks like I’m in for a busy 30 days!