Grounding Issues!

[jimmy]

If you've followed my adventures in installing new pots in my other thread, then you'll know about this little problem.

Yes, this deserves its own thread.

I get a crazy buzz when I have the volume on. But If I put my finger on the pickup, the buzz goes away!

What a mystery!

Again: '79 LP, two humbuckers!

Help me out, please!

 

[uOpt]

Re: Grounding Issues!

You didn't ground the pickup cover (or pickup base if you have no cover).

Do you have 4-conductor or 2-conductor wire?

 

[jimmy]

Re: Grounding Issues!

WHOA! Pickup base/cover? WTF? Mine didn't come with that.

They are 4 conductor. It's a 79 LP if that makes any difference.

 

[Lu_B]

Re: Grounding Issues!

WHOA! Pickup base/cover? WTF? Mine didn't come with that.

They are 4 conductor. It's a 79 LP if that makes any difference.

Might not have a cover but its definitely got a base

 

[Zhangliqun]

Re: Grounding Issues!

They mean baseplate, and your humbuckers definitely have one each. Does the hum also stop when you touch the bridge? If so, the bridge ground is disconnected somehow. If not, UOPT is probably right, the covers aren't grounded. Make sure they are soldered to the baseplate.

 

[ErikH]

Re: Grounding Issues!

If it is a 4-conductor pickup, the base is grounded by the bare wire.

Double check all the solder connections making sure none are cold.

Does it happen on one or both pickups?

How's the wiring at the switch?

How about the jack?

 

[jimmy]

Re: Grounding Issues!

Might not have a cover but its definitely got a base

They mean baseplate, and your humbuckers definitely have one each. Does the hum also stop when you touch the bridge? If so, the bridge ground is disconnected somehow. If not, UOPT is probably right, the covers aren't grounded. Make sure they are soldered to the baseplate.

If it is a 4-conductor pickup, the base is grounded by the bare wire.

Double check all the solder connections making sure none are cold.

Does it happen on one or both pickups?

How's the wiring at the switch?

How about the jack?

Thanks for all the replies, guys!

I'm not sure what you mean by "base."

The hum DOES NOT stop when I touch the bridge. It only stops when I touch the Bridge or Neck humbucker.

The hum happens on BOTH pickups. The wiring on the switch and jack are fine.

 

[ErikH]

Re: Grounding Issues!

By base we mean baseplate, the part where the mounting tabs are and that the coils are mounted to. That is the baseplate.

What pickups are they (make and model) and what wires are going where?

If Duncans, are the red/white soldered together AND covered with tape?

Is there a bare wire from the pickup going to ground?

 

[jimmy]

Re: Grounding Issues!

By base we mean baseplate, the part where the mounting tabs are and that the coils are mounted to. That is the baseplate.

What pickups are they (make and model) and what wires are going where?

If Duncans, are the red/white soldered together AND covered with tape?

Is there a bare wire from the pickup going to ground?

Hahahaha, I don't think I have a baseplate.

How do I install a new baseplate?

 

[ErikH]

Re: Grounding Issues!

You have to have a baseplate. It's the metal thing that the mounting tabs are a part of. Without a baseplate they coils wouldn't be affixed to anything. Flip the pickup over, that big hunk of metal is the baseplate.

What pickups are they (make and model) and what wires are going where?

 

[jimmy]

Re: Grounding Issues!

You have to have a baseplate. It's the metal thing that the mounting tabs are a part of. Without a baseplate they coils wouldn't be affixed to anything. Flip the pickup over, that big hunk of metal is the baseplate.

What pickups are they (make and model) and what wires are going where?

O0o0o0o0oH! The baseplate to the pickups!

For some reason, I was thinking about the little metal thing in the center of the pots, like in this picture:

(THIS IS NOT A PICTURE OF MY GUITAR, BTW)

The baseplates of my humbuckers are grounded to the back of the bridge and neck volume pots.

The Guitar's ground wire comes through the humbucker lead cavity. That's grounded to a metal base around the pickup selector switch.

HRM!

 

[ErikH]

Re: Grounding Issues!

Ok, now that we have that straightened out, answer this question (3rd time being asked).

What pickups are they (make and model) and what wires are going where?

 

[jimmy]

Re: Grounding Issues!

Ok, now that we have that straightened out, answer this question (3rd time being asked).

What pickups are they (make and model) and what wires are going where?

Jeez, sorry I didn't answer that before. Don't hate on me b/c I'm not an electronics expert.

Bill Lawrence in the Bridge: Black and Blue wires to ground (back of bridge pot); white is the hot lead; green and red are soldered together and insulated.

SH-1 in the neck: Black is hot; green and bare are grounded to the back of the neck volume pot; red and white are soldered together and insulated.

 

[ErikH]

Re: Grounding Issues!

Not hating, just making sure all the info is put out there for a proper diagnosis. Answering questions has nothing to do with being an electronics expert.

The wires are going to the right places. The Bill Lawrence is obviously a Bill & Becky model due to the blue wire so you're good there.

The only thing I can recommend is to go through every solder point that you touched and remelt the solder and let it harden again. It might be wise to even redo the ground connections to make sure they are solid. It could be as simple as that.

 

[jimmy]

Re: Grounding Issues!

Not hating, just making sure all the info is put out there for a proper diagnosis. Answering questions has nothing to do with being an electronics expert.

The wires are going to the right places. The Bill Lawrence is obviously a Bill & Becky model due to the blue wire so you're good there.

The only thing I can recommend is to go through every solder point that you touched and remelt the solder and let it harden again. It might be wise to even redo the ground connections to make sure they are solid. It could be as simple as that.

Hrmmmmmmmmmmmmmmmmm. . .

I'm not sure what it is. Everything is solid. Any other ideas about why it's getting that crazy hum?

Why does it stop humming when I touch a pickup? That's the strangest part.

 

[Sporky McGuffin]

Re: Grounding Issues!

You have two issues.

1) The bridge isn't grounded.
2) The guitar isn't adequately shielded.

When you touch the pickups they are grounding you - not the other way 'round.

 

[jimmy]

Re: Grounding Issues!

You have two issues.

1) The bridge isn't grounded.
2) The guitar isn't adequately shielded.

When you touch the pickups they are grounding you - not the other way 'round.

So how do I ground this thing? Where? Tell me!

 

[ErikH]

Re: Grounding Issues!

Reflow the solder joints and then listen for the noise again. If it's still happening, then other things have to be looked it.

It may require taking it to a tech. Since you live in L.A., perhaps one of the experienced forum bros might be able to help you out in person if that is necessary.

This isn't a "this is the problem, this is how you fix it" scenario. There's too many variables involved and each one of them needs to be looked at individually.

 

[Sporky McGuffin]

Re: Grounding Issues!

That's a bit trickier!

There ought to be a wire coming from one of the bridge posts into the control cavity. You'd connect that to one of your grounding points on a pot or similar. If there isn't then you could have one fitted but it'd be a fiddly job - drill a teeny hole to where the bridge post base is and get a wire in and attached there.

For the shielding a good slop of conductive paint in all the cavities or some copper tape would do the job.

 

[jimmy]

Re: Grounding Issues!

Reflow the solder joints and then listen for the noise again. If it's still happening, then other things have to be looked it.

It may require taking it to a tech. Since you live in L.A., perhaps one of the experienced forum bros might be able to help you out in person if that is necessary.

This isn't a "this is the problem, this is how you fix it" scenario. There's too many variables involved and each one of them needs to be looked at individually.

Good idea!

That's a bit trickier!

There ought to be a wire coming from one of the bridge posts into the control cavity. You'd connect that to one of your grounding points on a pot or similar. If there isn't then you could have one fitted but it'd be a fiddly job - drill a teeny hole to where the bridge post base is and get a wire in and attached there.

For the shielding a good slop of conductive paint in all the cavities or some copper tape would do the job.

There isn't a ground wire. The ground wire I have is one that is soldered onto a metal ring in the pickup selector cavity. I've also looked for a ground wire from the bridge post, but there isn't even a hole in the guitar for one.

What's going on!?!?!!