Ungrounded pickup cover?

[TManiac]

Just bought a used ESP LTD EC-400VF (Les Paul type axe).

It has a JB/59' setup with humbuckers.

After I bought it I noticed quite a bit of hum. Did some debugging and it looks like the bridge cover is not grounded. If I touch it the hum gets crazy.

Before I crack her open... How is this normally grounded? Is the cover soldered to the base plate? Is that likely the issue or is the ground wire more likely the culprit?

No biggie just though I'd try and get insight.

Other than that the guitar rules.

Thanks
TManiac

 

[ehdwuld]

Re: Ungrounded pickup cover?

touch cover and more buzz?

what about the strings or the other cover?

do those make buzz too?

is the buzz like what you would hear if you grabbed the unplugged
guitar chord?>

 

[TManiac]

Re: Ungrounded pickup cover?

Yep, way more loud buzz/hum.

Touching strings and other cover decrease buzz/hum.

I used a multimeter as well. Neck cover grounded, bridge cover not grounded.

Hmm... it might be like that... do you suspect a short?

Thanks Ehd

TMANIAC

 

[PoorMan]

Re: Ungrounded pickup cover?

How is this normally grounded? Is the cover soldered to the base plate?

Yes.

 

[TManiac]

Re: Ungrounded pickup cover?

Yes.

Hmm... Unlikely that separate probably. Hopefuly a loose wire and not internal malfunction.

 

[PoorMan]

Re: Ungrounded pickup cover?

Hmm... Unlikely that separate probably. Hopefuly a loose wire and not internal malfunction.

You have to check the entire circuit for the ground. The cover is grounded by soldering to the baseplate, but the baseplate is not the source ground...it's grounded by a wire that (probably) eventually makes it's way via a connection to the bridge, bridge stud, trem claw, etc.

So you might have a bad connection/ground and it's not actually the pickup.

 

[TManiac]

Re: Ungrounded pickup cover?

Just for completeness...

The pickup was wired all wrong... Shielding wasn't grounded, black and green wired together etcetc. I think it was like this from the factory too...

Anyways, rewired the pickup and much better. Still a little hum that isn't reduced by touching strings, but thats probably a shielding issue.

Thanks everyone.
TManiac

 

[Guitar Lab]

I’m wiring a tele and the diagram says to ground the cover by clipping the connection to the tab on the pickup cover. It doesn’t touch the cover. I want it done properly but, having never done this before, I’m concerned about ruining the pup. Any suggestions?
Thanks,
B

 

[beaubrummels]

I’m wiring a tele and the diagram says to ground the cover by clipping the connection to the tab on the pickup cover. It doesn’t touch the cover. I want it done properly but, having never done this before, I’m concerned about ruining the pup. Any suggestions?
Thanks,
B

Those instructions don't make sense. Clipping the connection to the tab on the pickup cover is removing the ground.

 

[freefrog]

I’m wiring a tele and the diagram says to ground the cover by clipping the connection to the tab on the pickup cover. It doesn’t touch the cover. I want it done properly but, having never done this before, I’m concerned about ruining the pup. Any suggestions?
Thanks,
B

Hi,
IF the goal is to use a 4 positions switch and/or to allow out of phase wiring, the cover must be grounded separately from the coil. In such a "case", a separate wire must be added from cover to ground... It's not difficult and it shouldn't ruin the pickup. Instructions below...

https://www.fralinpickups.com/2018/05/22/convert-neck-pickup-to-a-3-wire/

 

[Guitar Lab]

You’re right, it doesn’t make sense. I neglected important information, my apologies. I am wiring a four way switch. I’ve read the Lindy Fralin article and it makes sense now. Thanks for your input, and for the Fralun link.