Odd earthing issue on Precision pickup

[Steve Browning]

Hi collective. I wonder if someone can point me in the right direction on a problem that has me stumped.

 

I am swapping out the pickup in my bitsa P-bass. I have a Lindy Fralin pickup that seems to have a earthing issue on the coil that has the white cable link to the other coil (which seems to have no issue) and then has the white cable to the volume pot. To give a complete picture, the cavity is completely lined with copper shielding tape.

 

I am struggling to figure out how one coil has this issue when the other doesn't, and they're linked at the tone pot anyway. It's a Kiogon loom and the bridge earth and pickup earth are joined at the block as instructed.

 

Any thoughts?

[Hellzero]

Is the copper shielding grounded?

[Steve Browning]

1 hour ago, Hellzero said:

Is the copper shielding grounded?

 

I would be inclined to say no. I say that because it’s just in the cavity and don't see any deliberate attempt to earth it. 

[Woodinblack]

I am not sure what you mean here with the white cable to the other coil.

So you have two pickup pieces (actually two independent pickups), one connects to volume, one connects to earth somewhere and a cable connects the two together?

So which part of the pickup isn't working - did you try the output of just one part of the pickup pieces?

[Steve Browning]

Just now, Woodinblack said:

I am not sure what you mean here with the white cable to the other coil.

So you have two pickup pieces (actually two independent pickups), one connects to volume, one connects to earth somewhere and a cable connects the two together?

So which part of the pickup isn't working - did you try the output of just one part of the pickup pieces?

Both parts of the pickup work. The one that connects to volume will hum when handled and the other one is silent. 

[Woodinblack]

But if you are not handling it then it is ok?

[KiOgon]

Do you have  multimeter? It's possible that the coil windings are shorting out.

 

What do you mean by; "and they're linked at the tone pot anyway"?

 

Cheerz, John

[Steve Browning]

4 minutes ago, KiOgon said:

Do you have  multimeter? It's possible that the coil windings are shorting out.

 

What do you mean by; "and they're linked at the tone pot anyway"?

 

Cheerz, John

Well done. You spotted my deliberate mistake. The block is on the volume pot. 

 

I would presume the pickup wouldn't work if it was shorted. Silent was a poor term to use. 

 

I'll do a short video tomorrow and post it. I'm explaining it very badly. 

[Hellzero]

Ground the shielding, the problem will be solved. It's a more than common issue with badly made shieldings.

Edited August 13, 2023 by Hellzero
Spelling and big fingers.

[Steve Browning]

Here's the issue. Not quite Cecil B DeMille but you get the idea,  hopefully. 

[Aidan63]

so the shielding isn't 'earthed' and the screw on the apparently noisy pickup is in contact with the shielding by the looks of it, nothing to do with the pickups, the screw isn't electrically connected to the pickup it's just holding the cover in place, the foam is isolating the back of the pickup from the shielding

[Hellzero]

Exactly what I said earlier, the shielding is not grounded... The bridge must be grounded too.

[sandy_r]

[not needed on journey]

Edited February 21 by sandy_r