I have been asked to look at a friends Marshall JH-1 'Jackhammer' pedal after he 'dropped it'.

The foot-switch activates the 'active' red LED but as soon as a jack is inserted into the 'In' mono jack socket the light goes out and there is no signal throughput. With foot-switch in the 'off' position the signal bypass works fine.

I have now replaced the mono jack input socket (as it was very worn) and also the DPDT foot-switch but with no change.

Any suggestions greatfully received.