Help troubleshooting malfunctioning Northgate Omnikey

[intelli78]

I have a Northgate Omnikey like this (http://media.engadget.com/img/product/11/8i4/northgate-computers-omnikey-102-hsv.jpg).

It is functional except for the following keys, which do not work:

F3, F9, Tab, q, w, e, r, u, o, a,s, d, j, k, l, semicolon, x, c, m, Lalt, space, left arrow, down arrow, right arrow.

Some info:

- I have cleaned all of the switches recently; none seem damaged or worn out.

- If I disassemble a working switch and press the leaf against the contact with a screwdriver or Qtip, the key registers. For dead keys, this is NOT the case, so I do not think the problem is in the switch internals. Thinking it's the PCB or a chip, but I'm really not sure.

-  The keyboard was working in the past, but got exposed to some gnarly Arizona heat; this could maybe have something to do with it. I don't know.

- The dead keys seem to be in clusters for the most part. Coincidence? you tell me.

Anyone more knowledgeable about electronics able to speculate on what's happening with this board?  I can do basic multimeter / soldering work but I don't have the knowledge to figure this out myself.

[jabar]

Well have you tested connections with the multi?

[intelli78]

I performed the most basic level of troubleshooting -- testing continuity of the switches -- and found that all of these had simply gone bad. I opened a few and there was corrosion in the ALPS "gold sandwich." So, the problem was less serious than I had suspected. I have a blue ALPS donor board on the way and will solder in some replacements.