How can I track down a grounding problem on my guitar?

K

KaBudokan

New member
I recently changed the pickups around on an old beater guitar I've had for a while. I had some Duncan Hot Rails in it before. While I was waiting for my Lawrence pickups to arrive, I changed the wiring scheme to experiment a little. I did a weird rigging I had found with a 5 way switch, using the tone control as a blender. (This is on a tele-style setup - two single coils, volume, tone.)

The wiring worked, but there was a horrible ground problem. I figured it was just a by-product of my weird wiring I was trying. I was planning on going with a Standard tele wiring scheme when the Lawrence pickups arrived.

Well, they got here, and I still have a bad ground problem. It isn't the pickups - it's something else. I've tried to figure it out, but can't. What steps should I take to track it down? (I don't have a multimeter, but can get one if I need to.)

Thanks!
 
Have you made sure that your wiring is identical to the standard tele wiring scheme?

You should also check out some alternative grounding methods. I'll try to find a site for ya.
 
Thanks, but I've been there, done that.

I can only think of two possible things:

The ground wire on the jack came disconnected. Unfortunately, because this guitar is cheap and older, one screw on the jack has deteriorated and I can't get it off - it is starting to strip - so I can't get the jack off to check.

Or the wire I used - cheap Radio Shack 24 gauge hookup wire - is causing some kind of problem.

I even rewired the guitar exactly how it was wired before, and the problem was still there (and it wasn't before I messed with the wiring).
 
make sure you check all the places that you soldered when you wired it. you could have a bad weld or a spot you soldered could be touching a ground.
 
Not all but most of the time I've encountered this, it's the ground wire going to the bridge. This is especially common on guitars that have a painted bridge. The manufacturer doesn't scrape enough paint away on the bottom side of the bridge to get a proper ground. If you can get a meter it's easy to see without taking the bridge off. Just ohm from the ground of the jack to the bridge. If it's anything more than 0 ohms, you've got a problem. Another dead giveaway is that the buzz will go away when you touch the strings. Hope this helps.
 
One thing to do, in fact now I think of it a couple of things to do.
First double check your soldered joints, you could have a dry joint.
Get some plumbers soldering flux, it's dark and looks like axle grease, but it is vital to making a good joint, even if you have rosin cored solder use the flux, it gives really good results, and don't breathe in the fumes they are carcinogenic, and if you are an asthmatic they'll give your lungs shit.

With the bridge joint, this is where the flux pays for itself. Clean the area to be soldered, use a file not emery tape as tape leaves dust which you don't want.

Then keep your sticky fingers away as fingers leave grease, sweat and acid on the surface.

If you have the time look up the guitarnuts.com site, they have an excellent set of instructions on shielding guitars, also I suggest you replace the jack.
Good luck.
Clive
 
OK - weirdness.

I picked up a Digital Multimeter at RS. First of all, it's a piece of crap, and is going back first chance I get. I'll get an analog one - not because it's vintage... lol

The bridge "seems" to be grounded ok. However... this is weird. When I check the reading on the actual strings, the high E and B strings show they are grounded, and the other 4 (G-E) aren't. This is also what happens when I touch the guitar - the buzz ONLY goes away when I touch the E or B string, not the lower 4.

Any ideas WTF is going on? :mad:
 
OK...Here's another thing you can try to eliminate or confirm that the ground wire going to the bridge is/isn't the culprit. Hook up a clip lead from a good ground in the electronics cavity of the guitar or the 1/4" input and clip it temporarily to one of the strings. If the buzz goes away, you've got to remove the bridge and make sure/reconnect the ground wire. If the unit has a floating trem, this can be less difficult because usually the ground is soldered to a plate in the cavity and is carried through the tension springs to the bridge. If this is the case, make sure the springs are not painted (I've seen this also). If the springs are painted, scrape the paint off where they connect to the bridge and to the plate. You could have something completely different going on, but I've seen these situations alot. Just tryin' to help. Good luck on tracking down your problem.
 
Alert: Did you shield the cavity? When changing out any pickups, especially "hot" ones and multi-position switches, it is a good idea to line the cavity with copper shilding. Even in the best of grounding senarios a poorly shielded cavity can allow signals to run amuck.
 
Thanks Monte, but it doesn't seem to be the bridge. I tried your siggestion, and again, no change. The only thing that stops the buzz is when I touch the high E or B string, or one of the other metal components. Or the shielding tape in the cavity of the guitar. Or the jack.

You get the idea. I guess I will go through and resolder everything, but I am pretty positive that isn't it.
 
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