Unicomp Model M: Some keys / key combinations don't emit any scancodes.

[Professor Fate]

Howdy!

I still have a minor issue with my 122-key (German layout) Model M: Some keys resp. key combos are ignored! I've tried out everything with xev to find out that the following combinations are apparently ignored:

• Caps Lock: Ignored.
• Page Down: Ignored.
• Ctrl + X: With the left Ctrl key, everything works fine, but with the right one, only the scancode of the Ctrl key itself is registered, whereas the X keystroke is ignored.
• Alt + (Shift +) S: With the right Alt key I'm using as ISO Level 3 Shift, the Alt keystroke itself is registered, whereas the S keystroke is ignored.

I have already opened the chassis to remove and debris and removed & reattached the controller PCB. The hammers are all in place.

Is this an issue with the controller firmware? And: How can I get rid of it? Thank you.

[Professor Fate]

OK, the guys at Unicomp told me there had to be an issue with the contacts of the PgDn key. So I disassembled the (already screw-modded) board, found nothing abnormal, re-assembled the board — and still have the abovementioned issue. See the pictures attached.





What's still wrong here? Does anybody know that?