I just rewired a J pass to have a series parallel switch, and put in new pots all around. The bridge volume pot works fine until the very end, where the sound just cuts off. It seems like a bad pot, but I don't know for sure. Expert advice if anyone has it.
Some people have done the "nailpolish mod" on their tone controls... It sounds to me like maybe the resistive element at the end of the rotation may be blocked by a piece of debris or something. Try cleaning out the pot and see if that helps.