we’ve got one E key that has in the past exhibited greater sensitivity than all the other keys. At present, it sounds fine, but I suspect a cushion problem that will recur. Anyone have a recommendation as to which one is the most likely culprit?
https://www.syntaur.com/DIYdocs/DIY0012.html
A common problem is a faulty/dirty rubber contact strip, which causes either a note to not play at all, or alternatively, a note to play at full velocity even when played softly. It sounds like perhaps the latter may be happening. You can swap it with another strip elsewhere in the keybed to see if the problem moves with the contact strip. If so, try washing the faulty strip in warm water with dish soap, and if that doesn’t help, replace it - we have them available.
Yep. There’s two rubber pads, the time difference between the two making contact determines velocity. What usually happens is some dust, dirt, grit etc drops between the keys and gets under the strip. Some light cleaning with a q-tip/cotton bud is usually enough. You probably can get away with just cleaning with a dry q-tip. But don’t rub the contact strip contact too hard as you will remove the conductive coating, that black on the q-tip is that coating, some sort of graphite or carbon.