AVRI Jaguar Ground Buzz

[Bandarra]

Hi,

Maybe someone can help me.

My AVRI Jag is making big ground noise. Is not the amp, not the cables, its the guitar.
I tested everything I could with a multimeter and found nothing wrong, except for this glazier point (in the the volume/tone cavity) that is not grounded. The solder on it is loose.
My question is: Glazier points should be grounded or they are there just to keep the copper plate in place? May this be the ground problem I was desperatly looking for?
Im a complete electronic noob by the way.

picture:



thank you in advance

[timtam]

Glazier points are just to keep the plates in place. It's the wiring of the plates that not only grounds each plate (for shielding purposes) but also distributes ground throughout the guitar to wherever it is needed in the circuit. If any of those solder joints for the wiring were bad, you wouldn't have a circuit - parts of the guitar wouldn't work at all.

You didn't describe the exact symptoms. Is this new, or has it always been like this ? Is the noise worse when not touching any guitar metal (strings/control plates) ? Either way, what happens when you do touch guitar metal ?

[Bandarra]

Thank your for you're reponse on the glazier points


I really dont remember if this noise was always like this, but I dont think so beacause it didnt bother me that much before. I know its been this way for a while now, but im pretty certain it gotten worse recently. I plug my brother's single coil strat and is dead silent, I plug the jag and is an annoying buzz. This buzz goes away almost completely if I touch the strings or metal parts and gets bigger if I turn the volume knob half-way off. In the rythm circuit is a little less. Dont think this qualifies as 60's cycle hum and from my internet search I concluded that is ground noise.
I checked the ground wire under the tremolo, the ground wire next do the back pickup, every copper plate, I checked all the connectons that I could with a multimeter and nothing seems wrong. This is becoming out of my league.

[Bandarra]

In the meanwhile there are some changes.
I sat down doing a little thinking. Im pretty sure that when I bought the guitar this buzz/hum didnt exist (at least so notorious). But I know that this noise is there for quite a while. So, what happened? What did I change in the guitar?
1. I've changed pickguard. No problem there for sure, the shielding plate is there the same way.
2. I've changed the bridge for a Mustang bridge. But Im pretty sure this is not the problem since I tested it a thousand time.
3. Finally I changed the pickups heights long ago. The back one up and the front pickup down. So, the front pickup was the only place I couldnt check with the multimeter beacause is stuck. Maybe the problem was there. So for some testing I unloose the pickup screws to make it turn to the original position closer to the strings and voilá. There is a change, the buzz/hum is much lower. Now I feel there's something wrong under that pickup needing some check up.
Let me describe the sound righ now. The buzz/hum is there (not so loud) and almost completeley goes away if i touch the strings or any metal. Then, even if I let go the strings the noise dont get worse, but if i knock the strings just a bit (even with little or no sound) the buzz gets significantly louder.
Now Im in need of 2 advices: about this noise and how to loose the front pickup to see what goes under without destroying it or any connections.

[timtam]

So firstly, noise that reduces or goes away when you touch guitar metal is a sign of a properly grounded guitar. Your body is a big antenna for airborne EMR interference. If you are in a noisy EMR environment, touching grounded metal grounds you so the noise reduces. Nicely shown here ...
https://www.youtube.com/watch?v=SQU85rklIgQ

So, what your noise symptoms mean is that (1) you are in a noisy environment, and (2) your guitar is grounded, and (3) your single-coil jag is particularly subject to picking up that EMR noise (some SC models are more subject than others).

From your expanded symptom description it's still hard to say what else is going on. The poor way in which jag pickups are mounted - screws into wood, with foam underneath - and with grounded plates in the bottom of the cavity, and exposed/bare terminals on the underside of the pickups (on the pickup and on the claw), makes fertile ground for problems to arise.

If I were you, I would first unscrew the trem to easily remove the strings (with something wrapped around the strings at the body end of the neck to stop them flopping around). Then remove the pickguard, and unscrew the "front" (neck ?) pickup to explore underneath (be careful with the wood screws, as they can break). See if you can reproduce the noise symptoms with the pickup away from the body, and then with it back in place.

The greater noise when 'knocking the strings' is unusual. Place one probe of your multimeter on the bridge/strings and the other on the (grounded) rim of the output jack when you do that, to see if the ground connection is being disrupted. The test should show ~0 ohms when normal (that is, correctly grounded strings). Then at the jack on other end of your guitar cable, place one probe on the tip (hot) and the other on the shaft (ground) and repeat the knocking test. The test should not show zero ohms when normal (that is, no short between hot and ground).

I assume from your description that the main control plate and the lead and rhythm switch plates have not been off the guitar. If so, they can be excluded for now.

[Bandarra]

The problem is solved. The neck pickup was to deep in the cavity and was causing that noise.

The guitar is now dead silent on the rhythm circuit and make some minor noise on the lead circuit but I supose this is normal.
Comparing it now with other single coil guitar the noise is the the same, so if any problem exists lies in the cables/amp/pedals/environment.

thank you so much for your help and sorry for the delay in posting again.