Pedal gain knob not working (signal does pass)

[msb69]

I've got an OD pedal that passes signal when the pedal turned on, but the gain knob seems to have no effect at all when turned.  The volume and tone knobs seem to work fine.

What's up here?

[MarcoMike]

more info on the "kind" of od pedal?!

could be the ground lug, if any, is disconnected, could be the pot is gone... could be something else...

[msb69]

It's an overdrive in the Tube Screamer family, running off a 4558 op amp

[slacker]

If it used to work properly and now doesn't then it's probably a broken wire to the gain pot or a damaged pot. If it's never worked then it's probably a wiring error round the pot, or something is shorted out that shouldn't be.