Just received a Pbass from someone that has a bit of a grounding problem somewhere... light to moderate hum. (FYI.. Problem was well known before the sale, no issues there. ) Here's what I do know about it: Bridge ground wire isn't soldered, but it is locked in contact with bare metal on the bridge. Bass hums very little when nothing is touching it, hums LOUDLY when touching only the pickup mounting screws, and STOPS humming when the bridge is touched (with fingers, in both cases.) Help an electronics noob out a bit! Also.. any tips on soldering the ground to the (black) bridge? I tried many times (after stripping a spot on the underside to bare metal and heating the bridge waaay too hot to touch...) I gave up after a while and stripped the finish off the inside of the middle mounting screw hole and pulled the bare wire up through it, then locked it down with the mounting screw.