deskthority

Hello !

I have a keyboard where a number of keys have stopped working, pretty sure its not mechanical issues but electronics in the board. The keyboard in question is a OEM Key Tronic "foam and foil" keyboard from the early 80s, it was manufactured by a Swedish company called Luxor for a computer called ABC 806. I have in total of 3 keyboards where different pads have stopped working and I cant figure out why, here is an image of the keyboard:
The keyboard uses the Intel 8049H keyboard controller and a XR 950-3B scan driver and something like a 3 pin 7805 voltage regulator.

Any tips, comments or ideas are very welcome, I love to get this board working so I can use my computer.

Is the foam in the switches still okay? Over time, it can disintegrate and interfere with switch operation.

The foam in the 'foam and foil' has disintegrated, so the foil doesn't make contact with the pads anymore. You can make new ones yourself (workshop-f7/1983-general-radio-genrad-l ... 19531.html) or buy pre-made ones (https://texelec.com/product/foam-capaci ... keytronic/), but I don't recommend that, it's way cheaper to do it yourself. Good luck with the project!

Hi guys, thanks for the quick reply.

All foam is replaced with the ones from Texelc, the reason I suspect the electronics is that I switched between 2 different circuit boards and the keys not working was different on both boards, despite using the same switches.