My Zenith Z-150's F7 key seems to be a bit wonky. The keyboard has a toggleable feature to fire a small buzzer on each keypress. When that is turned on, pressing the F7 key will cause a beep. However, SwitchHitter and other keyboard testing software I've tried (as well as general applications) does not register the F7 key as being pressed (on both OSX and Win 7). Every other key works without issue (though OSX doesn't like its NumLock for whatever reason).
What should I start poking with my multimeter, and how?
I would start by seeing if the switch has connectivity. If the switch doesn't register connectivity at all, I'd resolder the joint. If that doesn't work, I'd try swapping in another switch. I know SKCM Greens are kinda hard to find though so maybe swapping in a switch from like Scroll Lock or some rarely used switch might be ok. And then use Matias replacements until you find another SKCM Green.
Switch is totally fine, manually bridged the connection between the two leads, same thing happens. Some portion of the board is registering the key as pressed, as it fires the beeper. I've visually inspected the components around that switch and the circuits running to/from the switch and there doesn't appear to be anything damaged or improperly soldered. I'm just stumped that it's firing the beeper but not sending the scancode.
Guess I need to examine the matrix more carefully? I have to imagine the issue lies somewhere in the circuit for the single switch, as no surrounding switches are acting abnormal, and there's no other funny behavior from the board. It's a single-layer PCB too, so I suppose it's not too difficult to see where things are routed, but I've little experience troubleshooting circuits.