TLC Ideas for LA120 Keyboard?

Jeffrey, the contacts you describe from your LA120 (cannot look at my own right now) seem to be similar to what I saw in a VT100 keyboard. This keyboard had been stored in a place were mice and rabbits lived, but it recovered plastic has a cleaning effect on the electrical contacts as it slides between them. In general, I often have success when cleaning contacts by wiping them with paper: it's rough enough to remove corrosive layers, but soft enough to keep the contacts intact, and it's readily available. Best way to apply is: put paper between contact fingers while the switch is open, then close switch, and, while applying little or no additional pressure on the contacts, move paper back and forth a bit. You will sometimes see a line left on the paper, especially if the contacts are very dirty. This line proves that the method works. Given the limited space around your keyboard contacts, you'll probably want to cut a narrow stripe of paper, insert it with the help of a screwdriver because you cannot open the contacts otherwise, then take out the screwdriver and just pull out the paper from under the contact. For this type of mechanical contact, a chemical solvent may also be appropriate. I don't use contact cleaners on variable resistors (and some other stuff) because it solves the problem only for a limited time, and when the problem reappears afterwards, it's worse than before. A "volume" potentiometer treated this way will crackle even louder in about a month or two. BTW: nice ASCII graphics! :-) Andreas Jeffrey Sharp wrote: ... -- Andreas Freiherr Vishay Semiconductor GmbH, Heilbronn, Germany http://www.vishay.com