I just bought a Music Man OLP from my friend for 50$. It sounds ok, the bass works and all but the electronics are screwed. The first knob from what i can tell has no effect. The 2nd knob turns off the volume if the 1st knob is closed all the way. The third knob (Treble?) is smashed off completly. Anybody know how I can fix the knobs and get a new 3rd knob? and how much money i'd be looking at?