Sylvia Else wrote:
The sustaining pedal on my Yamaha electronic piano is become rather
flaky. Sometimes it doesn't sustain when pressed.

So I disassembled the piano enough to get at the mechanism, (removed 12
screws, and 6 bolts), and was rather surprised to see that the business
end consists of a potentiometre.

I'm not really surprised that it's failing. In fact, the surprise is
that it's lasted so long. When a piano is played, the sustaining pedal
is in constant use. I can't help feeling potentiometres were never
designed with that kind of use in mind.

The design seems rather primitive.

Sylvia.

Google for a servo potentiometer,
or a conductive plastic potentiometer.
They are expensive, but are mechanically strong and
have a live of milions of cycles.