Gibson Triumph Les Paul Bass Wiring/Controls

[Grog]

This was a NOS control assembly. I bought it mostly to get the control plate, which I switched right away. The sellers mother was a former worker from the Kalamazoo Gibson factory. This was about fifteen years ago. He seemed to know many of the retired / former Gibson employees & what they may have had stashed away from the closed factory. Just about anything I needed, he could find me. Those were the days!!

[mark]

Well I soldered the green wire to the left lug of the switch.I soldered the 2 blacks to the ground lug. I soldered the 1 brown from the front pickup to the right lug. I bent the 2 center lugs together & soldered the pink to it. Now I have 1 brown from the front pickup left to solder. When I look at the schematic it shows the front pickup with the other brown wire going to ground. So I soldered that wire to the ground lug. I have sound, but now when you turn the bass tone pot up the volume goes up, & it is not the tone changing it's the volume. Now I am really confused.

[Granny Gremlin]

Where are those 2 black ground wires coming from going to?  One should come off the tone pot (lug 1 or 3; 1 is unused) and the other to a ground point (such as a pot casing or sleeve of the jack.  In Grog's pic, looks like it goes to the Vol pot case.

Also if that 0.15 cap on the tone pot is not connected (blown  'open' vs shorted, or just one side has a cold solder joint nor otherwise broken connection - check that the lead soldered to the tone pot case is actually making connection to the case) the tone pot will act as a variable resistive pad.

[mark]

One black wire comes off the phase switch to ground & one black wire comes off ground on the pickup switch & grounds on the volume pot. This one looks like Grog' picture as well. Every thing looks good as far as solder joints on the bass tone pot.I am not real tech as far as testing capacitors & don't know how to test them. Just an observation not related to the problem. The body appears to have a 1/8" piece of maple sandwiched between the mahogany like some les pauls of that era. I always thought that they were solid mahogany.

[Granny Gremlin]

Caps are 20c; just replace it (keep it in case that wasn't the issue for originality' I guess).

[mark]

I went to radio shack yesterday. They didn't have a .15 cap so I bought a .22 cap instead. Gonna try & work on it tonight.

[Basvarken]

The body appears to have a 1/8" piece of maple sandwiched between the mahogany like some les pauls of that era. I always thought that they were solid mahogany.

It's a mahogany veneer that was turned 90 degrees, so it lays cross grain to the rest of the front and back.

[mark]

Well I finally got to replace the .15 cap with a .22 & guess what it worked !!! Have full control of bass tone with no volume increase Thanks for the help guys.

[Granny Gremlin]

beauty; glad that worked out.