Gibson BR-1 Volume pot

[Quincy56]

So I am working on a vintage Gibson BR-1 and the instruments channel pot is very dirty. I'm going to try and clean it, but I may just want to replace it. it looks like from my ohmmeter it is 640K. Online I'm finding 500K and 1M pots. My assumption is I should go with a 1M instead of the 500K.

The schematic I could find did not show a value. It is the one tied to the two 1/4" inputs.

http://www.prowessamplifiers.com/sch...Gibson/br1.pdf

John Adams

[Jazz P Bass]

Try measuring the potentiometer 'out of circuit'.
Here is a copy of the BR-4 that shows the control as a 500K.
Gibson_BR4_schematic.pdf

[Quincy56]

I measured the resistance after I took it out. Measured 640K. So my question is should I go with 1M or 500K? Doesn't seem like I will find a 640K. I see on the BR4 the mic input is 1M and the tone is also 1M. Maybe this pot has increased in value over time.

[Enzo]

It is just a guitar amp, the value is not critical. Try just cleaning it first. The volume control is just a simple voltage divider, so what matters is the ratio between sides of the pot while turning it. Either value will work fine. besides, pots were notoriously loose tolerances, that one may have measured 640k when it was new.

[Helmholtz]

Maybe this pot has increased in value over time.

Yes, resistance increases by wear (carbon track abrasion).

But as Enzo days, it could be just wide tolerance and doesn't really matter.

[olddawg]

Probably says 500 on the pot somewhere. Will probably clean up if it isn’t seizing.