The pickup has a magnetic core with light gauge enameled wire wound around the core. Check wire continuity with an ohm meter. All the pickups should have similar resistance, the position of the selector switch/volume controls might make some variance between them. Unless they've been roughly treated I doubt if wire in the pickup is broken. My guess would be either the selector switch, if it has one, or the pots (volume controls). The pots have a carbon path that can deteriorate, or the sweep contact might be tarnished. I use to have a liquid treatment for pots, but I don't remember it's name. A lot of people are using CRC Contact Cleaner now (I have NOT personally tried it). This post was edited by spacecadet9 at 21:23:33 04/13/14.