It sounds like it could be an internal pot issue. I hope not for your sake as they are a pain to break open and replace but doable. It all depends on how long yours has been out in the wx. I found once I got my apart that I also had to replace a bunch of bearings, but that was nearly 10 years ago and so far so good.

Before you go doing this though mKe sure that your wife connections topside are solid. I've also had problems with that more than once. They can work loose.

Good luck 73 Rick W2JAZ