My Yamaha FC7 expression pedal is causing volume freak-outs on whatever Part is engaged. It occurs whether or not my foot is on it. The volume slider is moving, fast, up and down, and randomly.

I’ve got three FC7 pedals and each has some issue or other. This was the only one working properly and now it’s acting up. 

Is it worth taking it apart? I know nothing of electronics and not sure what I’d be looking for or actually be able to do—other then to use some contact cleaner spray.

Does the symptom (random slider volume changes) indicate anything in particular? And something that could possibly be replaced? 

FYI I live in Central America. There are no instrument repair shops or GC’s in this country. I’m pretty much on my own UNLESS I could possibly find a general electronic-y sort of person but I would need to explain things to some extent.

I CAN order a part and have it shipped from U.S. and delivered to me within a few weeks.(I could just order a new pedal, but I’d dearly love to not own FOUR FC7s.)

Suggestions, please!