IBM Model M2 stuck on Scroll and Caps Lock, no keys reacting

Question

Today I tried out an old M2 for the first time with an USB/P2 adapter. For the first 10 minutes it worked fine. Then I set it aside on my desk, left the room for a second, came back and suddenly the caps lock and scroll lock lamps were on and not a single key reacts anymore. Nothing has fallen onto the keyboard and the keys are not stuck. I already replugged the board and restarted the computer, and the two lamps went back on immediately.

I run Fedora Linux on a mid-2011 Mac mini and would be thankful for any advice.

Answer 1

It's probable that the capacitors on the controller PCB have failed -- this seems to be a common fault with M2 keyboards.

There are various pages that walk through how to replace them, for example this one. There are two capacitors to replace: one is 2.2uF 50v and the other is 47uF 16v.