Troubleshoot self-build

BigPaulie

https://flic.kr/p/2pgwQw8

I built this years ago and have recently rediscovered it. It is a Catalinbread Galileo clone built from this layout

https://tagboardeffects.blogspot.com/2012/10/catalinbread-galileo.html?m=1

The input side footswitch is a treble booster which works fine.

The output side footswitch goes to an AC30 style overdrive circuit. When this is engaged I get a very low output signal with tonnes of static. The gain and volume controls work within the limitations of the low output level. Bass when turned up fully almost seems to cut the output of entirely. Treble doesn't really do anything, but may just be very subtle.

Any hints for troubleshooting will be gratefully received.

https://flic.kr/s/aHBqjB3TUc