[Solved] Help me diagnose a wiring issue on a Les Paul

[HotRats]

Background: I've brought one of my Les Paul to a new (to me) luthier to replace both volume pots.
Is not close to my home so I don't want to go back to him if I can do it myself.

Back home, with my rig, I've noticed that bridge pickup didn't sound right turning the volume down and didn't cut off 100% when set to zero either.

In middle position turning down the bridge volume doesn't seem to really affect the tone and doesn't cut off volume when set to zero

Neck pickup seems to work fine.

I've checked all the connections with a multimeter and all solderings are ok.

is it possible be that he inverted lug 1 (from pick up) and 2 (to selector) on the bridge pot?

Forgot to say, the Les Paul has 50s wiring

 

[Byrdman]

Possibly. Sounds to me that a tone pot was possibly used for a volume pot. I would start there and see if you can pull numbers off the pots. Post up some pics. What kind of wiring modern vs 50's? Check Caps, could be a bad one maybe.

I have done a few and getting ready to rewire my LP this week, but maybe someone with more experience will respond.

 

[HotRats]

 

[HotRats]

Possibly. Sounds to me that a tone pot was possibly used for a volume pot. I would start there and see if you can pull numbers off the pots. Post up some pics. What kind of wiring modern vs 50's? Check Caps, could be a bad one maybe.

I have done a few and getting ready to rewire my LP this week, but maybe someone with more experience will respond.

I've replaced volume pots only because they started developing issues.
I gave him the pots, they are both new original Gibson volume pots I bought myself.

 

[Eagle]

If the volume pot on the bridge pickup doesn't work in isolation and displays the same problem in the middle position IT is probably the issue. Check around for a bit of solder or scrap of wire getting somewhere it shouldn't partial shorts etc. Also blow out the pot with compressed air and use some switch cleaner on it . I suspect you will need to replace it. You can try to see if it works when you take the loom out of the guitar as well to see if you can diagnose it.

 

[HotRats]

Haven't tried to swap lugs 1 & 2 connection yet but I've read that if you wire them backwards you get independent volume controls (meaning that in middle position they won't interact) with the downside of much more treble loss when turning down the volume just like is happening to my bridge pickup.

I'll try to find the time to do it later today.

'Independent' or 'Decoupled' wired volume controls
So with the more traditional, commonly found dependant wired controls briefly covered above. Let's look and how those volume controls can be wired to function 'independently' so to speak. It's simply done by reversing the above connections regarding the input and output of the volume pot. Your pickup signal wire now needs to be connected to the middle, sweeper 'output' lug of the volume pot. With the switch wire to the 'input' lug of the volume pot instead. This style of wiring and how the controls work may suddenly become familiar to you if you have ever played, or wired up say, a Fender Jazz bass for example. This allows the volume controls to work somewhat independently to each other, but it's not quite as simple as putting the cover back on and enjoying your new decoupled controls. You've essentially changed the way the pickups and circuit interact, which does actually affect resistance. What that means is you will likely experience a more dramatic effect on the treble frequencies through even minor adjustments to each volume control. So although this still happens with dependant volume controls, it is far less drastic than with this wiring method.

 

[nicolasrivera]

Also try to separate this a bit from the ground.

 

[HotRats]

SOLVED!

inverted lugs 1 & 2 and everything is back to normal.

Electricity will always be a mistery to me, LOL

 

[Byrdman]

SOLVED!

inverted lugs 1 & 2 and everything is back to normal.

Electricity will always be a mistery to me, LOL

Right on!! Glad you got it done! I'll be working on mine sometime this week. I'll hit you up if I run into any snags

 

[HotRats]

Right on!! Glad you got it done! I'll be working on mine sometime this week. I'll hit you up if I run into any snags

I've bought a new soldering iron for this work, one with a variety of points and the flat one worked much, much better than the thin one I had on the previous iron.

Took me literally 5 minutes, maybe less.

 

[Byrdman]

I've bought a new soldering iron for this work, one with a variety of points and the flat one worked much, much better than the thin one I had on the previous iron.

Took me literally 5 minutes, maybe less.

The last time I did this, I upgraded all the wiring in my Epi ES-335 when I put Gibson Classic 57's in it, so I'm not worried about it too much. Really the only thing I dread is attaching the ground braid of the PU wire to the top of the pots. That, IMO, is always the pain in the ass of the project. Sometimes the solder sticks just fine, other times you have to do it over and over to get a good solder connection.

Most of the time, if you scratch the bottom of the pot, apply plenty of, but not too much, solder suave, say a few Hail Mary's while doing the sign of the cross, cross your toes, and it solders just fine. Other times, the devil is intentionally screwing with you...

 

[HotRats]

LOL.

you're a brave man, @Byrdman, rewiring a 335 style guitar looks like a pain in the ass anyway.

 

[Byrdman]

LOL.

you're a brave man, @Byrdman, rewiring a 335 style guitar looks like a pain in the ass anyway.

It was a HUGE pain in the ass with everything going through the f hole and I really dont want to do that again unless I absolutely have to.

Here is my secret that made it easier. I took a piece of rubber fuel line for a weedeater I had laying around the garage, put it through the hole for the pot and then attached it to the knob stub and then pulled it back through the proper hole. They did fall off a few times when they hit something inside the body, but it worked eventually.