Sweet Honey Overdrive always on full volume

[Bluefinger]

Hi,
All of a sudden my mad professor sweet honey seems to be on full volume all the time. The pot does not have any effect anymore. What's the most likely reason for this or best way to find out? As it's the PCB version I would like to keep fumbling to a minimum. The only thing I have done so far is to resolder the volume pot connections.
Schematic attached for reference
thanks!!!!

[Helmholtz]

Use your Ohmmeter to check if pin 1 of the vol. pot is well grounded.

If yes, the pot might be broken internally.
Remove it from circuit and check its function with meter.