I have two A500+ keyboards, one Samsung with a big return key, and one Mitsumi, with a small return and two blank keys.
Both have faults. On one of them, the Amiga keys and some others don't seem to work, and on the other, the Esc and '~ keys don't work.
I have looked at the membranes and can't see any obvious faults.
Is there much chance that one of the semiconductors on the PCB could be faulty?
I have another spare Mitsumi keyboard somewhere, which i would test, but I can't find it.
Thanks 
steve30
I have the same problems on two keyboards. They look OK, maybe it is the controller.
