What's wrong with this picture?

[D. Scott Nettleton]

The other day I was working on an electric guitar that quite a few folks had already had their hands in. Something was wrong with it, but nobody was quite sure what it was. I could determine that the signal from the neck pickup was leaking to ground, but not how. I checked and rechecked all the wiring, as well as the pickups and pots. Finally after an hour of fumbling about, I took a photo of the wiring so that I could study it at home and move on to another project.  I looked at it off and on over the weekend, but never quite figured out what was wrong.

Finally, I came in to work on the next Monday and found decided to replace the wires between pots. As I was removing the wire from one of the tone pots, it suddenly dawned on me: the third terminal was in perfect contact with the conductive paint shielding the control cavity. I looked at my photo and found that the problem had been clearly visible the whole time. If the cavity had been shielded with copper or aluminum it would have been obvious, and yet my mind simply did not put two and two together.

For some reason, I felt like sharing this to contribute to the community, and to serve as a dire warning to others...

--D. Scott Nettleton

[FRANK]

looks like your pin 1 or pin 3 was touching the side ?and grounding out

[Russell Vance]

Hi Scott,
Electric guitars have way to bite us that Leo Fender never imagined......I've been doing electrics for a long time and have adopted a process that seem contrary to everything I learned as an electronics technician in a previous life:

When it doesn't make sense and looking in all the normal places yield no results I have found that I can strip an electric to individual components and rebuild/test with know good components until the problem goes away in a relatively short period of time. It sounds unprofessional but everyone has had the experience of an difficult instrument taking forever or being left on the repair shelf because it is too hard, I just pull them apart test everything in isolation and put it back together in standard configurations which seem to be more effective than signal path analysis. Particularly good for finding broken wires that are just resting on the 'break' enough to make contact on the bench but nasty when the noise starts. Rusty.

[Pierre-Antoine Roiron]

I've had the same problem some month ago. Kind of tricky, isn't it?
Good idea to share it. I'll do the same next time!

[Pierre-Antoine Roiron]

Here's one I just found last week : EMG sells now their pickups with a lot of no soldering clipping ends (don't know the english word, sorry). If the wiring shematics seems ok and you're still in trouble, check these clipping ends. I found one with a random short cut. I've had a hard time finding it... believe me!