Boss MT-2 Metalzone - not working properly

[Bainzy]

I was doing some mods on this that I know are correct (things like removing nasally mids), and I had the pedal working beautfully. I was testing it with the board outside of the enclosure, and all of the sudden the sound cuts out. For some reason now I don't get as much distortion, the pedal is too quiet, and unless the smaller mid control is turned up I get extremely weak distortion. The gain (distortion) control no longer works. The switching mechanism works fine. The EQ controls don't work too well, they're really really subtle now.

One thing I've noticed is if I jumper two wires on the PCB, I can get the pedal to work, the EQ controls work fine, but the distortion is stuck on maximum.

Any ideas? I really need this pedal fixed ASAP as I'm modding it as a favour for someone.