Dead Keys

[Dae]

I picked up a cheap old keyboard today, a Yamaha PortaSound. When powered on it immediately made a continuous tone, and had two unresponsive keys (one of which corresponded to the note of the tone). Although I know nothing about electronics, I took it apart to see if there was anything obviously gunked up that I could clean.

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Sure enough, the relevant contacts looked corroded.

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A guide I Googled recommended 90% isopropyl alcohol to clean with. The best thing I could find was my girlfriend's flatmate's nail polish remover...

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Since cleaning up the contacts as best I could, the keyboard functions properly, but the dead keys haven't come to life. The contacts appear quite damaged – removing the blue-green gunk revealed a bronze surface (not obvious in the picture), rather than the black visible elsewhere. I don't know if it's worth spending an hour getting the rest of the corrosion off, or if there might be other issues at play.

Can anyone offer any advice?

 

[MikeMl]

Typical when Coke is spilled in it.

 

[Nigel Goodwin]

Typical when Coke is spilled in it.

Yes, nasty stuff coke - the copper tracks at the top look like they may be rotted away, or it may be the black contacts themselves.

 

[Dae]

Anything I can do?

 

[Dr_Doggy]

solder it, or even a conductive grease may help(not my best idea)

you can see where the node has detached, bypass the dead node with a wire to another node point, if ya hafta

use a ohmmeter to check for the open circuit if you can

your dead key is #5, and prolly #3?