This is the primitive wiring diagram that I made for an ESB-4 type bass. It has developed a problem with the bridge pickup. Not sure how clear the diagram is. This bass has push-pull switches on the Volume pots. In the normal (down) position, the bridge pickup is humbucking. In the up position only the Red/White coil is activated.
That's the way it always worked. But a few days ago the pup stopped working with the switch in the down position. With the switch in the up position, single coil mode was still working. With the switch down, humbucking position made no sound at all.
So, I disconnected the green and white wires from the switch, and connected them to each other. That should have bypassed the switch and put the pickup in humbucking mode. Still no sound. I checked the to see that the black wire was well grounded (earthed) and it had a good connection.
What that makes me think is that there is a break either in the green lead or the black lead somewhere between the switch and the pickup (unlikely) or that one of the wires inside the green/black coil has broken (likely).
So can anyone think of another possible problem I can test, or am I dealing with a busted pickup?
These pickups are Bill Lawrence EB-50's. I just put a review of them on the aftermarket parts forum, because I really like them and there were a few available on Reverb/eBay. Since I hadn't seen any since about 2018, I thought I'd share my joy. When I checked a few minutes ago there was only one left. So I bought it. These pickups sound great, and are dead quiet when you are not playing. In spite of that neither of the companies that make BL pups make this particular model anymore.
I will feel a bit stupid, and about $60 lighter, if my current pickup is fine. Nevertheless, I am hoping that the last known replacement in existence arrives safely. The bobbins are the wrong color...but you can't hear the color of the bobbins....