I have a 1989 Fender Jazz Special, PJ configuration, all stock. It's fretless, with a Precision body, though it's labelled as a Jazz from the factory. I love the bass, but when I include the J pickup in the mix, I get a great deal of hum. I've taken it to two repair shops and they insist there's nothing wrong with the wiring, nor the pickups, nor the instrument itself. It's just the old 60-cycle hum, they say. Does anyone have any ideas for eliminating it, other than playing forever on only the P pickup setting? I play in a church choir where there's lots of quiet time, so even the least hum can't be tolerated. I thought of replacing the J pickup with a Fender Noiseless. Any ideas, suggestions, rants, raves? Thanks much.