This Music-Man Bass Guitar came in with a dead preamp.

You gotta love preamps potted in an epoxy resin.

Start by removing the wires.

Take note of where the wires go and dissasemble.

Remove the epoxy resin (very carefully) while drawing the circuit diagram on paper.

Then clean the pcb and start rebuilding.

New components and wire.

Cover the pcb in heat shrink tubing.

Re-attach the wires to the jack and pots.

Strap the board in with cable ties.

And place back into guitar.