dbmaustralia

A few months ago I purchased a used Relay G30. To begin with I had no issues and used it every time. Then one day U lost all of my distortion sound from my pedal and only a clean tone will emit. I tried changing batteries, cable tones and channel, but no affect. I know its nothing else between my guitar and amp because if I remove the G30 and plug direct into my pedal, the full distortion sound returns. Any help or advice please...