#2
The neck is backfeeding the bridge? Did someone bring this to you for repair? If you turn the neck volume down, are you still getting signal through the bridge? I'd completely gut it, check the resistance of that bridge, and re-wire. I wouldn't be surprised if the bridge is dead and someone who didn't know how to check it was getting creative to try and make it work.

Please be sure to post the outcome. I'm curious.
"Quick to judge. Quick to anger. Slow to understand. Ignorance and prejudice and fear walk hand-in-hand."
- Rush, "Witch Hunt"
#3
The PUP is dead. With both volumes full on the two pups are effectively just wired in parallel so that indicates it is open circuit. Desolder it from the volume control, noting which way the wires go and then get a meter on it. It should measure a few kilohms. If it doesn't it is dead.

The foam is acting as a spring to make the height of the pup adjustable. The copper film is shielding to cut down on electrical noise. No idea of what the powder is unless it is some sort of conductive paint to shield the cavity.

On the volume pots the centre terminal is the output to the jack/tone control and the top one the input from the hot end of the pup. the bottom one is earth.

Hope that all helps.
#4
D'oh! As an electrician, I am very embarrassed that I missed the parallel pickups. My AC/DC professor would be disappointed. I spent more time helping others in those classes than doing anything else.
"Quick to judge. Quick to anger. Slow to understand. Ignorance and prejudice and fear walk hand-in-hand."
- Rush, "Witch Hunt"
#5
Quote by Phil Starr


On the volume pots the centre terminal is the output to the jack/tone control and the top one the input from the hot end of the pup. the bottom one is earth.

Hope that all helps.


I don't understand why if this is the case that every wiring diagram I am seeing shows wiring the pickup into the middle?

https://www.google.com/search?espv=2&biw=1476&bih=867&tbm=isch&sa=1&q=jazz+bass+wiring&oq=jazz+bass+wiring&gs_l=img.3..0l5j0i30l2j0i5i30l3.107497.109171.0.109324.16.13.0.0.0.0.208.1373.0j8j1.9.0....0...1c.1.64.img..7.9.1372.UI15JIXWHIM#imgrc=_
#6
Pickup was bad. I took apart and found out the end of the winding was unsoldered from the point that connects to the leads. Sanded the wire and then soldered it and was back in business.