Greetings!!
A few months ago, I posted about my X68000 computer repair.
It's a good news/bad news situation. The bad news is that the system I had turned out to be outside my knowledge to repair. I can see it was on the cusp of powering up, but had some insidious problem in the power management system, I think. Something was trapping the CPU in a bus-requested state and never returning control. I cut my losses and sold the machine as a parts machine. I managed to recoup about 99% of what I paid for it, including postage from Japan, so absolutely could have gone worse!
The GOOD news is that not long after that, I obtained another system, this time an X68000 PRO, in fully working condition, with refurbished power supply, serviced floppy drives, and an all-important boot floppy containing Human68K OS 2.01. It fired right up, works perfectly.
It still needed some work. First, the power supply is an inefficient supply from the 80s, and runs exclusively on 100V. I replaced the guts with a modern ATX power supply, switchable between 120 and 240V. Runs cooler, smoother rails, and will last much much longer.
Next, the SRAM battery was dead. Unlike other systems in the series, which have time-bomb 3.6v barrel-style NiMH batteries, the PRO has a plain old CR2450, albeit one that is soldered in. A simple replacement with a CR2032 holder, and that is taken care of.
Finally, I have no keyboard or mouse for it. They are expensive, $500+ for a loose keyboard!! I decided to build an adaptor, and although there are numerous designs floating around the Internet, they:
- Use old, obsolete microcontrollers
- Use sketchy Arduino USB host shields
- Are super expensive
.... soooooo I designed my own, using a Raspberry Pi Pico microcontroller (RP2040). A few dozen lines of C code later, I have a design that is simple to build, uses modern, abundantly available hardware, and uses nearly any USB keyboard and mouse. I'm going to do a short prodution run, and make the designs available open-source for the future.
With all the basics checked off, I decided to do some upgrades. I obtained a Centronics50-to-DB25 SCSI cable, to connect an external ZuluSCSI, loaded up with games and apps. That's storage sorted. I also got a PCB and components to build up the so-called "GALs Panic" RAM expansion, which adds 10MB on top of the system's internal 2MB. It was a relatively simple build, but it was a chance to try out my new microscope.
Now I'm FINALLY at a point where I can enjoy the system. What a ride!!
Here's some visual goodies to enjoy!
My USB adaptor design:
https://www.youtube.com/watch?v=GtF3Zh8TsY4
Early design of PCB:
https://i.imgur.com/pOigjD1.jp
The RAM board I built:
https://i.imgur.com/3If6eU7.png
It passed the test!!:
https://i.imgur.com/CZ54mXt.png
Floppy drive ASMR:
https://www.youtube.com/watch?v=Bn4wFdbCEmw
Cheers,
RetroSwim
--- Ezycom V2.15g1 01FD0295
* Origin: >> Pool's Open - The RetroSwim BBS (21:2/121)
