Osborne 1 keyboard repair?

[Patrik Schindler]

Hello Tom,

Am 21.09.2020 um 13:41 schrieb Tom Hunter via cctalk <cctalk at classiccmp.org>:

> Has anyone got experience repairing or restoring this type of membrane keyboard mechanism used in the Osborne 1 and probably in other keyboards too?

Not with the Osbornes, but with others. This kind is cheaper to manufacture than the ones with "true switches".

Anyway, to get rid of the problem, carefully heat the ground plate to "does not hurt if I touch it for 10 seconds" and remove all the spring housings. Punctual further heating is most likely needed. This enables you to separate the sheets, and clean them. This should remove remains of soft drink spills (possibly explaining your particular problem), as well as insulating black silver sulphide layers.

I Germany we have a very mild solvent for electronics, proved to do wonders to this type of partly-conductive foils.

https://www.amazon.de/KONTAKT-CHEMIE-71809-Tuner-Kontaktreiniger/dp/B000NI2NTA

Maybe there's something similar where you live?

Also, carefully inspect the foils if there's some mechanical damage, like dents on the actual contact spots, providing a contact all the time. If there are, there's some creativity needed to even them out. I never needed to do that.

> Here are some good and detailed photos of keyboard mechanism:
> 
> https://www.flickr.com/photos/123564336@N03/sets/72157644113347562/

Thanks, this helped a lot!

:wq! PoC

PGP-Key: DDD3 4ABF 6413 38DE - https://www.pocnet.net/poc-key.asc