I have a Yamaha P-105 with some dead keys - they bottom three D keys, the bottom two A flat keys and the C in the sixth octave.
I’ve cleaned the contacts (‘the internet’ indicated that might be a solution for such a problem) - didn’t work. I tried switching around the rubber contact strips to see if they were the problem - the same keys are dead, so I concluded they weren’t.
Have replaced the contact board for the lower section (certain that would fix it ) and no change…
Anyone have any ideas? Only thing left I can think of is the main board - but I think that would be prohibitively expensive