Grounding problem?

[Willie_Green]

Hi Guys & Girls.
Hi this is my first time post, and i was wondering if any of you kind souls can help. I recently made a set of humbuckers, and set them to a fellow in America. I hooke them up before sending and tested, and all was fine.
The gentleman i sent them to has installed them... the bridge is fine, but he says the neck only works when he touches the poles or the hight adjustment screws??
I wonder if this is something stupid that i am missing.
Any advise that i can give him would be helpful.
P.S it is 4 conductor hookup wire.
Thanks

[David King]

Welcome to the forum Willie!
That is a strange set of circumstances but I think it would be easy to test out some theories with a length of wire from the Jack nut (ground) and then touching to the pole pieces and the height adjustment screws to see if that causes it to work.
It seems likely to me that the pickup is somehow shorted out and touching it is moving it slightly and un-shorting it.
Is there a metal cover on the pickup or are the coils exposed?
Did your customer put a conductive paint or foil shield in the pickup cavity?
Is there any chance that a screw penetrated the pickup wire and cut through to a conductor/s?

[eschertron]

Have your customer check the wiring he did inside the cavity. My hypothesis if that they don't have a ground (common) path. The ground is completed when they touch the grounded parts of the pickup.

[big_teee]

It can all be easily tested with a guitar, a cord, a VOM, with the vol. pot on high.
Plug the cord in the guitar and check Ohms from the tip to sleeve, or ground.
Test from Sleeve to pickup baseplate, or Pot backs.
Sounds like the ground is open, or shorted somewhere as previously mentioned.
T

[Jim Darr]

Welcome to the forum Willie,

Some good advice given from the other forum members. I suggest the following for troubleshooting your situation:

1. Review your notes or memory to be sure you wired it correctly when you made it. Probably not the issue since you indicated you tested it and it sounded okay.

2. I would confirm that the pickup was wired in the guitar correctly with a common/proper ground. Improper grounding in the pickup or guitar wiring can cause all types of hard to find problems. Even a bad solder joint can cause major issues. If a problem is detected, then correct as needed.

3. It might be an internal short corrected by putting pressure on the top of the pickup as David stated or it also could be an open connection as Big T suggested and putting pressure on the top of the bobbins completes the circuit. If either is the case it should happen by pressing on the pickup top in different places (other than the screws or poles) and also with an insulated or plastic probe. My guess is this is most likely the problem in that the pickup is shorted out until the pressure corrects the short. Note: It could be internal to the pickup, cavity ground shielding touching a hot connection, bad soldering, or improper wiring hookup, or mis- wired 4 conductor hookup, etc, etc.

4. If the problem, as stated in the original post, happens without much pressure it has to be a wiring issue. (exposed connection shorting out, wrong wiring, open connection, a mounting screw pierced the coil, etc, etc.

You did not mention if you were using commonly available plastic HB bobbins or you made them. I've made HB pickups out of Forbon with rod magnets (think smaller Fender style single coil bobbins using two bobbins in a HB configuration) and had problems with the coil magnet wire shorting out to the magnets causing either a buzz or no sound when touched.

Hope you figure it out and can keep the customer happy.

Good luck and keep us posted