Plus Top Pro with Push Push pots-Tone Pots suddenly stopped working

Deepmojoman

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I am STUMPED! Completely FLUMMOXED! I've reached the end of my solutions, and I need you guys' help.

I've had the aforementioned guitar-a 2013 model-since '15. Soon after purchasing it I replaced the sucky Push-Pull pots-the ones with the Molex connector; the ones whose stems often pull out-with the better Push Push models, and I have been happy with those for years.

For the past few months one or the other of the tone pots would just stop working. I'd open up the electronics compartment, jiggle a few wires and the pot would come back to life. So I knew that I had some imperfect wiring going on that I'd eventually have to get around to fixing.

Then last Monday I noticed that, once again, one of the tone pots had gone south. I opened up the compartment and found this time that jiggling wires didn't work. So I figured that whatever shorts in the wiring that I knew would eventually come to stay had, in fact, done just that, so I got out my gear and went to work.

To cut to the chase: NONE of it brought my tone pots back.

Here is a list of all the things I did:

1. I ended up replacing ALL the wiring-the set of wires coming from the pickup selector, as well as both sets of wires coming from both Pickups-twice. First I replaced the wiring with 18 ga solid wiring, and then later thought that the stiffness of the solid wiring was helping to pry soldered joints free on the replacement pots, so then I ended up replacing all the solid wire with more flexible stranded wire.

2. Both Push-Push pots have been completely replaced.

3. Both Tone Pots and their Caps have been completely checked and are working properly and to spec.

4. New Tone Pots were installed, along with new Caps, just to see if the problem was somehow the Tone Pots (even though, as mentioned before, all Pots/Caps checked out fine.) Installing the new Pots/Caps changed nothing.

5. All grounds have been continuity checked and are fine. Bridge to Neck Tone Pot, as per the included schematic.

6. Continuity tests have been run between the P/U Selector and the Electronics compartment, and all wires pass with flying colors.

7. The Pickups have been removed from their recesses and looked at for any signs of any abnormality. They are the stock Epiphone-designed models, and are sealed, and both look completely normal.

8. Through progressively rewiring more and more of the compartment, I have gotten the electroncs buttoned down better than perhaps they have ever been. No more "Jiggle Shorts" anywhere. And the tone seems to have gotten better (no surprise). Just: no ability to modulate the tone with the Tone Knobs.

So that's my story. The pic I am including is the schematic of the wiring. My wiring exactly matches the schematic.

How the Tone Pot modulates your tone is a fairly simple electronic affair, right? Signal comes into the Volume Pot via the red wire from either pickup, and is soldered to the leftmost lug. That lug is shared by a wire coming from the Tone Pot and-regardless of what wiring scheme you've chosen to wire your Tone Pots (from '50s, to Modern, and any mode in between,)-the high frequencies of the signal in the Volume Pot will be attenuated by the Cap attached to the Tone Pot, before exiting the Volume Pot via the middle lug.

As long as the Tone Pot is attenuating signal (which it is, in a constant sweep, from 0 to 500K ohms, as it should,) and the Cap is to spec (which it is: .022 uf), and there is a clear path for the attenuated high frequencies to escape to via a clear Ground (which there is), then this should work. And yet it doesn't

So does anyone have any insights?? I am completely stumped.
Les-Paul-Electronics-Wiring-Schematic-2.jpg
 
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Brian16Sg

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Does any of the wires have metal mesh on them? It reminds me of when redid my SG new pickups and compleet wiring harness pots,jack and selector switch. The problem i found after going through check things over and over again . I found my pickup wires had a metal mesh jacket . When i put the cover on the mesh was making contact and shorting things out. i ended up rapping over the mesh with electrical tape and it worked.
 

Deepmojoman

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Yes, there is wire mesh grounds that come out of both P/U wires and one that comes out of the Pickup Selector wire. All three of them have been securely shrink tubed with other ground wires, however. There's no shorts like this in the compartment. Honestly, I wish it were as simple as that, then I could fix it and be on my way.
 


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