I've recently done a mod on my Epiphone Les Paul Custom copy. Gibson 57in the neck and 57+ in the bridge. I pulled the 3-way switch from another guitar (that was working fine by the way) and put in the Epi. The only change I made in the wiring was to swap posts the orange drop caps go to and swapped the 2 wires from switch at the pots, as decried on installation sheet. The swap allows for blending of the neck and bridge, and use of center position with only 1 pot opened up (neck or bridge). When I switch to the center position quickly it makes an audible and loud pop thru the amp speaker. If I go to bridge or neck on the switch no popping sound, only in mid position.

Has anyone experienced this and what is the remedy?
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Last edited by Guitarpups at Mar 12, 2016,
that is a really interesting way they did the volume and tone, it's not unheard of to see the capacitor go to and from the tone. That I'm not sure if it would work based on how the capacitor connects to the volumes center lug mostly. The way I do it is connect the capacitor to the left lug on the volume in this perspective like 1950s gibson wirings considering it's 2 volume 2 tone anyways right?

for the switch that is odd that they would both not work in the middle position; either the switch is broken which I've never had happen before as heat can damage components but someone has to be absolutely terrible to ruin a switch which i mean in the most reassuring way possible (not trying to be negative)

how clean is the soldering on the switch? any old wires that were left from the previous guitar? does the switch touch anything inside the control cavity it shouldn't but reassurance. I've taken apart this kind apart once to see how they work on a quest for tone chasing and they would be really difficult to screw up

but fingers crossed it's just the wiring if so this will help, notice how the capacitors are done Worst case scenario try the switch in the guitar it came from again for reassurance. If anything. I mean this isn't an issue with the pickups , the input jack or pots. All capacitors do is hold onto stuff so it has to be either a wiring issue or something wrong with the switch which in my experience is unlikely. By the way when you put the orange drop in did you use heat sinks? they keep the capacitor from damaging.

good luck
Thanks for the comments on my mod. I'm thinking that there is no issues with the switch. I had the controls wired as you show it and there was no issues. It's only when I tried the wiring as in the diagram I've posted that here were issues. By the way, this diagram is what came with the pots from Stewart MacDonald. I've also emailed their tech team, but I won't hear back from them until Monday. I like the blending with the current wiring, although if it is going to reep havoc then I'll change back. The strange thing about the diagram I've posted is that the cap is tied to the ground on the case of the pot. I don't know if that would cause problems but I thought it strange. And yes I did use a heat sink to solder the caps.
Previously I had thought there was something wrong when having the switch in the middle and get nothing unless both bridge and neck are opened on the volume. But, that is how I was taught to adjust the volumes anyway (Crack open treble until you have a volume ,then Crack open neck until there is a volume). At any rate, I enjoy doing the mods, and this is the first time I have run across any issues.
What I was doing with this mod, is taking the pups and controls out of an lesser guitar and putting them in the epiphone. I had put the controls and pups in the other guitar before I acquired the epiphone. I will be putting the pups and controls I removed from the epiphone into the lesser guitar. The controls that were in the epiphone as well as the pups are decent, but I wanted the Gibson pups in it since it plays so much more nicer than the other guitar.
I will probably wait until I hear from the techs at StewMac before I dive into it again.
Once again, thanks for jumping in here with your knowledge.
When I heard back from the tech at StewMac, he just basically asked if the switch was damaged in some way or had some solder gunk down inside it.
I decided that since I don't play in a band setting and I'm not one to be switching while I play I need not worry about it.
Funny, I placed the old pups in the other les Paul copy (agile 2000) and had low volume on the bridge pot. After messing with it forever, I took the pot out and found that there was a very tiny sliver, very tiny...that was touching the mid lug from the hot. I removed that and in business. By the way, this guitar has the same pop when I go to center.position lol.
Oh, and the old guitar is not wired like the diagram I posted here. So that wiring had nothing to do with the popping. And further, if I have the amp in silent record and listen with headphones, it is dead silence. No popping at all. That is strange