From your video, it looks like it has something to do with the wiring of the bridge pickup. I've never come across this before, but the next thing to do is to take off the pickguard and examine the wiring, particularly from the bridge pickup to the switch.

And this is why I shield the daylights out of my Jaguars.
I put full shielding on the back of the pickguard, but then it too needs to be grounded to the chambers and the final ground leads.

Yes at this point I agree it has to be a grounding issue. I haven’t taken the pickguard off yet but I messed around with it this morning and it seems to have a mind of its own. I turned the amp on and for about the first 5 minutes there was no static at all and then all of a sudden it started. I also noticed for some strange reason it doesn’t do it with every finger. I can rub it with my index finger and it’s very pronounced but hardly does it at all with the other fingers. The pinkie does it slightly but the ring, middle and thumb produces no static at all. Also tried it while wearing a leather golf glove and it still did it but while wearing a rubber glove it didn’t. There’s also a low hum that goes away when I touch the chrome on any of the selector switches or pots but it doesn’t go away when I touch the strings, bridge or tailpiece. These kind of things drive me crazy but I’ll remove the pickguard later and see if anything stands out. Regardless I’ll be doing a thorough shielding job. Thanks for the link Synchro.

Last edited: Oct 19, 2024 10:43:05

Boomerang wrote:

Yes at this point I agree it has to be a grounding issue. I haven’t taken the pickguard off yet but I messed around with it this morning and it seems to have a mind of its own. I turned the amp on and for about the first 5 minutes there was no static at all and then all of a sudden it started. I also noticed for some strange reason it doesn’t do it with every finger. I can rub it with my index finger and it’s very pronounced but hardly does it at all with the other fingers. The pinkie does it slightly but the ring, middle and thumb produces no static at all. Also tried it while wearing a leather golf glove and it still did it but while wearing a rubber glove it didn’t. There’s also a low hum that goes away when I touch the chrome on any of the selector switches or pots but it doesn’t go away when I touch the strings, bridge or tailpiece. These kind of things drive me crazy but I’ll remove the pickguard later and see if anything stands out. Regardless I’ll be doing a thorough shielding job. Thanks for the link Synchro.

You don’t need a guitar tech, you need an exorcist.

All joking aside, it sounds as if you’ve got some grounding issues. The low hum is a common problem, but the fact that is goes away when you touch the chrome control plates, but not the strings, bridge or tailpiece suggests to me that your tailpiece or bridge (depending upon how they chose to ground the strings) are not properly bonded to the rest of the circuit. Take heart, this shouldn’t be that hard to fix.

There should be a wire with some bared insulation under the tailpiece, but it’s possible that it’s under one of the cups where the bridge mounts. The other end of that wire most likely is soldered to the back of one of the pots, and you want to verify that there is very low resistance between the tailpiece and the grounded side of the output jack. The same holds true if it’s grounded at a bridge cup, but if that’s the case, I’d simply check resistance from the bridge cup to ground, before I tore into anything. I would also check resistance from the various control plates to ground.

If there is more than a couple ohms resistance to ground at the bridge or tailpiece , I’d start by de-tensioning the strings and removing the tailpiece. A terrycloth hand towel will come in handy to prevent the bridge from damaging the finish while it is on the loose. At that point I would just install a new ground wire. If your guitar is bonded at the bridge, but has excessive resistance between the bridge and ground, I’d probably just snip that wire and bond to the tailpiece, although you would have to drill a small hole into the volume control cavity from the tailpiece cavity.

If you don’t see any problems with the tailpiece/bridge ground, then there may be a high resistance between the pickup selector control plate and ground. Just sort through it and you’re bound to find the culprit; a cold solder joint, or a missing ground.

In the same thread I linked to, Iceratz detailed the ground bus he created for the Jaguar he is rewiring. Between that and the shielding work he did, that Jaguar is about as hum proof as is mathematically possible.

If none of this works, hire an Exorcist, but be sure that the check clears the bank. If you fail to pay your exorcist, you might be repossessed. :j

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Boomerang wrote:

I took the pickguard off and didn’t notice anything unusual with the wiring but I haven’t pulled the switch covers or pots yet. Any particular reason the pickguard isn’t shielded? I’ve owned 2 other Squires before (a strat and a tele) and both had foil on the backside of the guard and never had grounding issues with either one. I also pulled the tailpiece and there’s no ground wire there so I’m assuming they grounded to the cups. I won’t know until I can put a meter on it and do some continuity checks. Right now my meter is dead so I’m going to go grab a 9v later. I’m now wondering if it’s even grounded anywhere. It’s definitely not grounded at the tailpiece but if it was grounded at the cups the hum should stop when I touch the strings shouldn’t it?

I’ll answer the last part first. If the hum is coming from somewhere else in the circuit, and the bridge were grounded, then touching it wouldn’t affect the hum. Only your continuity tester knows for sure.

I would definitely want the pickguard to be shielded and for that shield to connect to ground. I just looked up “pickguard shielding foil” on Amazon and there were even some 11.8” X 7.9” sheets, so you can solve that problem fairly easily. I’m surprised that it isn’t factory shielded.

I have a Squier CV ‘70s Jaguar, which has given me zero trouble, and is about as free of hum as any guitar I’ve ever owned. I’m afraid to touch it; if it ain’t broke, don’t break it.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Boomerang wrote:

What’s strange is the hum does stop when I touch any of the 3 chrome covers for the switches and pots. It makes me think that the wire coming from the cups to the back of one of the pots has either come loose or was never run in the first place. I’ll dig into it later and hopefully find an easy solution. I hope there’s a good ground wire coming from the cups because if there isn’t I would imagine that would be a pita to run. And if that’s the case I would probably run one to the tailpiece but that won’t be especially easy either since I would have to drill a new hole at an awkward angle. Oh well I’ve got plenty of other guitars to play until I get it done and I’ll be getting some of that foil on Amazon.

I built a Jaguar from Warmoth parts, last year, and decided to ground it at the tailpiece. You can probably fit a small drill bit into the tailpiece cavity and drill from there. That might mean drilling by hand, but I’ve heard that actually builds character. It looks like drilling to the bridge cups,would be a lot easier, but hopefully there’s a wire already in place, and it’s just a matter of terminating it.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Boomerang wrote:

Synchro if I decide to attach at the cup how do you actually attach it there? It seems you would have to remove the cup to solder the wire to it or do you just wedge it between the wood and the cup. Seems you would have to remove the cup either way and I’m not sure I want to mess with that. I watched a few videos of people pulling those cups and they either come out fairly easy or are a pita.

I think that they are just wedged in place. I’m not a fan of the design choice to ground at the bridge cups, but I can see that drilling the hole would be much easier. As you point out, the challenge is in removing the bridge cup, and there’s no way to know how that will go, until you actually do it.

As difficult as drilling from the tailpiece cavity to the control cavity would be, it might be the better choice.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Thanks for weighing in on this, Iceratz. IMHO, the trem’/tailpiece ground is the way to go, but if you have to drill for it, it’s going to be a real job, albeit one that pays off in the long run.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

IceratzSurf wrote:

I've never understood why the factory install of tremelo tailpiece is never grounded to the main control.

Probably a cost cutting measure, because of the challenge of drilling from the tailpiece cavity to the volume control cavity. This is a job for lasers!

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Boomerang wrote:

Solid advice and info everyone, I’ll be tearing into it deeper this afternoon to sort out exactly where the problem is and decide my course of action for a grounding point. More than likely I’m going to attempt to drill a hole to the tailpiece if the wire to the cup is the problem. When running a new wire to the tailpiece should I use solid core or stranded? Any particular gauge? I’m assuming this wire will not be soldered to the tailpiece but wedged between the plate and the wood.

Stranded, definitely. We’re not talking about kilowatts of juice here, so size isn’t much of an issue. 20 would be plenty thick, but basically any stranded wire should do. I just splay the strands and pin them with the tailpiece. A little piece of shielding tape will hold it in place, if you happen to have some on hand. Keep in mind, the pre CBS Fenders we all knew and loved were assembled quickly by workers who could be trained for most jobs relatively quickly, so they weren’t doing anything fancy.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.