I got my hands on a neat Random Technology KC-216 PC.
I played with it a bit, and it has some issues, but in general it worked ok-ish.
It uses a unique external PSU, with a DIN-5 plug that provides +12v, -12v and +5v.

This morning I tried turning the PSU on but it did not work anymore. I opened it and found that the fuse has blown. I replaced it with a similar fuse, and it immediately blew up.
I tried to troubleshoot the PSU, and found that there is a "short" between the +12 and the +5v. But it is not a dead-short, rather about 60-70 ohm. I think it is normal?

Since my history with fixing PSUs is not great, I thought about replacing it with a modern PSU. Ideally one that fits in the current PSU enclosure. The current board is about 14.5 x 7.5 cm.
I looked around, but was not able to find a small PSU that provides all the voltages. Any ideas?