Gain Pot issues

[Naterater3]

Hey guys, I have an issue with one of my first builds so I thought this would be the place to ask.
I've built a zehndrive OD and the effect works when engaged, the only caveat being the gain pot does nothing. The other 3 potentiometers which control treble before/after clipping, as well as a level control all function fine. I have checked my work and it seems to be solid, however the effect has no gain whatsoever. The layout for the effect can be found here: http://www.uk-electronic.de/Download/Manual%20Zehndrive.pdf
Any help is greatly appreciated!

[Elijah-Baley]

Did you get the whole kit and using all those components or just the board?
You know, in case there's something different in one of the part. It happened to me.

Start from here. I don't know what you checked already, but:
1. I'd check the pot with a multimeter and to see if the resistence works right.
2. Then I'd check if the pot's lugs 1, 2 and 3 are in the right position on the board.
3. The wires of the pot are well soldered?

Look again even if you already did all this, just to be sure.

[GibsonGM]

IF that doesn't work, look for BRIDGES from the output of the opamp to the input.   That means a connection that jumps (bypasses) the pot....could be a blob of solder at the pot connecting the wiper to the input side....same jumping over some diodes in that area...this is the most likely cause for your symptom.

If something is bypassing the pot, it is not in the mix so to speak, so it cannot work with input resistance to set the gain.  The schematic presentation for what is in that loop is on the last page of the PDF, so you can look to see which parts are involved in this...good place to start with schematics, too