I built either the DOD 250+ or Distortion+ a while back, can't remember which one it is - but either way; here's the problem that I have with it that should be a pretty easy diagnosis for someone with some knowledge...
It's basically got a volume and gain control, the volume works fine, but the gain control does nothing unless it's at 100% - that's when the effect engages and there's no actual gradual gain. When the gain knob is maxed, the effect comes on, at full gain...back off the gain a tad bit and the gain is totally off.
Is this simply a wrong gain pot or could it be a problem with the circuit?
Sounds like it...
reversing the outside lugs may help.
Using whatever reverio taper pot for the gain knob [specail taper IIRC]...
Or simply forgo the lower gain settings and use a 100k pot [mine has 22k pot], which spreads out the higher gain adjustability over a large pot range [pointer on knob can actually be used then], but loses the lower gain settings.