(A500+) more keyboard problems

[Zac67]

Unlike with other Amigas, the A500(+) generates _KBRESET within the keyboard - thus if the keys Ctrl, AmigaL, AmigaR work by themselves, it must be this _KBRESET line that's broken and not the keys.

Start on pin 3 (pin 5 is keyed) and follow it back to the keyboard controller or to JP1/Q711 on the mobo and Gary's pin 5.

[Zac67]

Sorry, didn't read the posts thoroughly.

Apart from the membrane, it could be the I/O pin of the KB controller - but I've never ever had that. Make sure the membrane traces, its connector and the leads to the controller are AOK. Measure conductance of each separately, the keypress can be simulated with a copper coin.

Exchanging the controller might not be worth it as it's not available new (only unprogrammed) and would have to be salvaged.

[Zac67]

Yes, I don't think there's any difference re the keyboards; the port is 100% identical.