Sorry, a bit of a long one. Continuing our look at the East German (DDR/GDR) Robotron KC 85 “small computer“. This was one tough machine to pull apart with thread lock glue on almost all the screws. Apple could learn a thing or two.
First the keyboard was disassembled. It has a metal fascia plate that appears to have been re-glued on. I decided to remove it and re-paint it ... maybe a divisive decision? The keys & components will be washed.
Next was the computer. I had noticed some minor issues around the board that needed repairing and I thought it better to repair first and test after. Looks like mostly a bunch of ceramic capacitors need replacing - I noticed also a bare pair of legs where one has been totally removed.
The piezo speaker wire also needs re-attaching to ... somewhere. I’ll probably replace the original wire with something a bit sturdier. The RF video output cable has also been chopped off so I will probably remove those components.
The power supply appears to be working fine - it outputs ±5VDC and 12VDC, with a Tesla-brand MA7812 linear regulator attached to a beefy heat sink. I might replace this (keeping the original part, not discarding it!) with a modern PSU6 replacement from .
Once the repairs are done, and an RGB video cable created, I will try to power the machine on in its disassembled state.
I am not looking forward to trying to re-assemble this fellow.
Stay tuned (if that’s okay)!