I bought an Epiphone Les Paul with a defective pickup off ebay for little money. "Defective pickup' is always only the symptom, and hardly ever the problem. You've a lot of guitar banging ahead if you want to knock out a cased humbucker pickup.

Anyway, the guitar sounded fine acoustically so I didn't hesistate. The neck pickup position was fine and in the combined setting (neck + bridge pu) I got a very slight sound from the bridge pu if I turned the neck volume down. So I was sure that the problem was a short somewhere in the bridge controls.



Original wiring seemed messy and ground is always carried on the shield wire of the insulated cable used, so the ground path close to the signal path in several places. A very bad idea if you want to prevent problems. One contact and your signal goes down the ground drain....



Selector switch was a potential culprit, but turned out innocent after the continuity tests.



Had to remove most of the circuitry to find the short, here's the back of the humbucker



In the end, there was no short, but the volume pot was dead, had infinite resistance (no contact) to the signal. So I ripped up a volume and tone control setup on a breadboard, to test out different caps and pots:




I ended up swaying to mojo talk and using a fat 400V 0;022uF polarized Erofoil cap whch tested ok. After trying different pots, I got the best range in tone control with a 100K pot, which is very unusual for a Gibson Les Paul. Everybody uses 500k, but nobody uses their ears or I'm competely missing something.