Ground wires from pickup cavities in KE3?

[MartinBarre]

My KE3 has wires screwed into the bottom of each pickup cavity (it's HH) leading to ground.
What the hell are these things for? I've never seen these in any other guitar.

This guitar is noisier than my other guitars, and I can find no reason for it, everything looks to be wired correctly. But I don't know what these wires in the cavities do.

Could they be touching the baseplates of my pickups and causing unwanted noise? Sometimes you can actually hear your arm touching the guitar body, as if the entire guitar has become a giant pickup! It's really weird, and really annoying!

[Hellbat]

They're to ground the shielding paint in the pickup cavities. If you are getting hum/buzz it's likely a bad ground/col solder joint somewhere in the mix.

[straycat]

Sounds like a cold solder joint on a ground wire.Just because it looks right doesn't mean it is wiggle the ground wire on the back of the pot.

[MartinBarre]

Thing is, I already replaced the pot. It's also different pickups from before, I even put in a new jack socket!
This is a problem I can't seem to get rid of.
It's not a major issue in the house but I'm planning on using the guitar for band rehearsal on Sunday and I'm worried it's going to be unusable at loud volumes.

[dg]

It sucks, but sometimes you've just got to go through them one at a time & re-solder. Sometimes the wire to the trem claw is the culprit, so you may want to start there. The claw is a big heat-sink that can be a bitch to solder to, so it's often the site of the bad joint. One trick is to drill a very small hole and feed the wire into it before soldering. Scuff it well, clean with alcohol, use plenty of flux, and you should be able to get a good solder joint there.

[MartinBarre]

Funny you should say that, I noticed yesterday that the trem claw joint WAS loose, so I resoldered it nice and tight. It's certainly helped things, but there's still this weird problem of the entire guitar appearing to function as a pickup when the bridge is selected. I mean, rubbing the body is amplified hugely - I've never come across anything like it before.
The guitar is still playable and actually sounds good, apart from this really odd fault.

[dg]

The bridge pickup may have gone microphonic on you. Could need to be re-potted.

[MartinBarre]

I wondered about that, but I just put an Invader in there a few weeks ago, and it was exactly the same when I had an old JB in it. The JB is now in another guitar and works fine so....

[MartinBarre]

Och, I'll be playing this thing at rehearsal tomorrow (with a backup ) maybe it'll be fine.

[dg]

OK, so you had the noise and since then you've replaced the pickup, the pot, the output jack, re-soldered the wire at the trem claw, and it's still there. Next thing I'd do is check or just re-solder the joints at the switch. One more possibility... I'm not familiar with how newer imports are wired, but on older C/Js there was a ground lug screwed into the side of the electronics cavity, much like the ones you found under your pickups. That's what grounded the shield paint in the cavity, and it could also be used as the central ground point. Does yours have one? If so, check to make sure it's grounded to the back of the pot with everything else, and that it has good solder joints.

[MartinBarre]

Yeah, there was one of those screws into the side of the control cavity. It fell out a while ago but I did rewire it back up again recently and it made no difference.
Does the shielding paint really need grounded? If the guitar is too noisy tomorrow I'm gonna try disconnecting those wires.

Thanks for the help BTW, I appreciate it!

[dg]

Does the shielding paint really need grounded?

In order for it to work, it does. Shielding paint acts as a Faraday cage, which shunts interference to ground, so without the ground it won't work.

[straycat]

Still sounds like there is a ground problem.Are the solder joints clean?Not saying you're a bubble gum solder guy but if the solder isn't applied properly freaky things like this happen.Is the ground to the jack soldered well?You may have one of the hairs of the hot or ground touching something it shouldn't.
I use cloth covered wire so I don't have these little problems.

[MartinBarre]

I'm not the best at soldering no, but I don't see anything obvious and like I say I've redid pretty much everything at one point or another.

I never got using the guitar today, as it wouldn't fit in the boot of my work car! Damn the Kelly and it's huge hard case!
I'll try it next time I go in a bigger car!