A500 keyboard - replaced the membrane but...

[tocster]

I am retoring an A500 that had issues with about 60% of the keys. I replaced the membrane and cleaned the plungers with IPA but the issue persists.

Asasuming the membrane and plungers are ok, what else could cause some keys to work and not others?

[Port89]

Originally Posted by tocster

I am retoring an A500 that had issues with about 60% of the keys.

Map out the keys and see if there's a common theme in terms of which membrane traces they are on.

That will be your start.

What brand of keyboard is it? I had some fun with one recently and ultimately it was fixable.

[jurassicman]

Have you already swapped the plungers (a few from keys that work in the place of few from keys that don't work and viceversa) to see if they are all good?

I read somewhere that to clean the plungers you should simply use some paper and that this way there are chances to "refurbish" them.

The issue could be in the PCB as well of course...