Absolutely stumped.

P

PDC

New member
I recently swapped out all of my plug-n-play EMGs for an assortment of Jalens and Duncans. All went well. I understand all of the basic principles of wiring and soldering. (Been playing and slapping guitars together for decades.) Not claiming to always make the ‘prettiest’ connections - but my work is clean and functional. The fact that all 5 guitars worked after the big changeover from actives to passives tells me that I at least I did something right 5 times in a row...

The other day I had one guitar start shorting out. I discovered that one of the press-fit tabs on the volume pot was wiggly - I could gently push it one way and get full signal - gently push it the other direction and no signal at all.

I thought I’d simply swap in a new pot this morning and I absolutely could not get a signal for anything. Ended up swapping the input jack - the volume pot - and even the pickup. Even pulled everything apart, stripped clean new ends on all the wires and started from scratch. Nothing. Dead.

At one point, I had full signal - quiet - no buzz and thought all was well, until I pressed the shaft of the volume pot through the hole in the guitar control cavity and everything went dead.

Is it possible that the bottoms of the lugs of the volume pot are contacting the copper shielding in the control cavity and grounding everything out? That’s the only thing I can think of, but if that’s it, I’m not sure why I didn’t run into this when I installed the copper shielding in the first place (?)

This is driving me crazy. Any thoughts or ideas greatly appreciated.
 
Re: Absolutely stumped.

Yes, that's the 1st thing to check. See if there are any spots where exposed hot wires can contact the shielding and put electrical tape over the shielding there.
 
Re: Absolutely stumped.

We have all been there. I once swapped in a new pot and nothing. I spent hours chasing down possible issues to no avail. Turns out the new pot was dead out of the bag. :smack: I swapped in another and bingo.

I cannibalized that one for parts and now test each part before installing.
 
Re: Absolutely stumped.

Crazy - and this was the Duncan Custom that I had just swapped the rough-cast UOA5 for the Ceramic, and it sounded fantastic! I ordered a bag of 4 CTS 500 short/split pots just to be sure I haven’t cooked the innards of my pot with multiple re-soldering. And I am going to lay a piece of black tape over the terminals before I install it. I understand I DO want the shaft / body of the pot to contact my copper shielding in the control cavity - just not the lugs.

It seems so darned simple!
 
Re: Absolutely stumped.

Is your amp... uhh... turned on? I'm only asking because in one project I wasn't getting a signal, and then found out that was the problem. Danged Standby switch!
 
Re: Absolutely stumped.

Copper Shielding! That was it. That and I had somehow removed the washer / lock washer that rides between the pot and the inside of the control cavity - so when I tightened the pot from above, it literally pulled up tight against the inside of the control cavity and the top surfaces of the lugs pressed into the copper shielding. I added the washer and lock washer and that bought me a tiny ‘air-gap’ between the pot and the copper shielding even when snugged down from above. I also put one small piece of black tape across where the lugs attach to the body of the pot for good measure. Learn sumthin’ new every day, huh? FWIW - the copper shielding makes a huge difference in keeping the guitar quiet as far as AC hum and buzz is concerned.
 
Re: Absolutely stumped.

^ Well it was certainly effective in noise removal- it removed the noise made by the pickups too.
 
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