I have (or at least had) a very nice Unicomp 101-key APL keyboard. So, I managed to get water into the key switches. I either spilled a glass of water on the keyboard, or I was cleaning it under a faucet, which ever sounds less stupid (hey, it's got drainage channels, right?). A couple keys start sending out multiple codes, and some are stuck on, etc, mostly toward the bottom row (shift key, and "X" sends out both X, and a period, for example). So I pop off the key caps & stems to let it dry out. Then a couple-three days later, I plug it in, and nothing is working.
Come to find out, after opening the keyboard case (which is what I should have done first), there was water pooled up int the bottom of the keyboard, which raised the humidity level of almost all the contacts so that the controller was registering the keys as all jammed. So I try drying a bit with a hair drier, and also sit it by a heat vent for a day or so. Next day, still no work. So I pop off the controller, check with an ohm meter by the contacts, and sure enough most of the contacts still show some continuity. Leaving it apart for a few more days seems to remedy the situation a bit more, but some columns of keys still weren't working. I'm thinking major damage must have happened from the hair dryer. So I pop off the rivets (at this point I'm prepared to go forward with a bolt mod), and further check the various traces. Turns out, it seems I had managed to scratch the traces on the plastic membrane (up close by the keyboard controller) with the leads from the ohm meter. Should be easy to fix, so I pick up a conductive pen from Radio Shack (cost me 20 bucks), and start to draw over the metal traces where it appears to be scratched. But I do a sloppy job, and I end up wiping off my mess (all by the leads where the keyboard controller makes contact), and end up wiping off the bulk of the existing circuit leads. Now I have to re-draw the traces with nothing to guide me.
Long story short, I quickly pound out some Postscript code to generate the appropriate circuit pattern, print it out, tape it under the plastic membrane, and proceed to re-draw the traces (this time with a bit more sleep behind me, and a large magnifying glass). Not perfect, but it seams to do the job. The ohm meter shows that everything check out (I'm being a bit more careful this time not to scratch anything); all that's left to do is to finish the bolt mod. It will take a week or so before I get another few hours of time for this, so meanwhile I need to make sure I don't lose any of the loose pieces (the springs / hammers, and key caps).
Meanwhile, I finally get a response from a ticket I opened with Unicomp. They are willing to sell the membrane for 10 bucks (cheaper than what I paid for the circuit tracing pen). They now have the membranes up on their web site in the spare parts section (thanks to my inquiry). I'm tempted to just order it and be done with, instead of trusting my repair job. I just which I hadn't spent $20 on the circuit writer pen.
