bad keys on terminals

... I fixed one of my PET 8032 keyboards in a similar manner - the keyboard uses plungers to push circles of conductive rubber against pairs of interleaved "fingers" etched onto the board - this particular PET had been sitting a LONG time and the conductive rubber had increased in resistance so much that almost all the keys did not work at all - some of them would work if you really pushed down, but all were much higher resistance than I measured on other PET keyboards - cleaning etc. made no difference. So what I ended up doing was cutting small squares of tinfoil and using bits of tape, I fixed one over each set of "fingers" etched on the board - then bent them up slightly so that they did not connect unless pushed down. I fastened them to the board instead of the plungers for several reasons: - Taping them to the board was easier than gluing them to plungers, and less risk of contamination on the contact from glue. - By fastening them to the board they would not "move around" with the motion of the plungers - preventing undue wear from the metal on metal (don't know if this would really be an issue or not). - Completely reversable - no glue, no holes or other modifications. The only thing I might have to do to remove it would be to clean some tape residue from the board. It worked very well, and the keyboard is going strong a couple of years later. I probably would look for a better solution if this were an "everyday" machine, however it's mostly used for the occational demonstration etc.so the keyboard does not see a whole lot of use. Dave BTW: I have similar vintage PETs with identical keyboards in which the conductive rubber is fine ... anyone know what conditions accelerate the deterioration of conductive rubber? -- dave06a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.classiccmp.org/dunfield/index.html