Hello. I have a PC2x that I’m trying to repair for my company. There are 2 black keys that are slow to return. I replaced the return spring on both, with some improvement in function, but the keys are still slower to return than they should (one is much slower than the other). Cleaning the mechanics of those keys didn’t make any obvious difference and the hammer weights seem to be intact. What am I missing here?
Did you try swapping them with two good keys?