Hey there. I have an old q tron plus that isn't filtering the way it should. Im using the EHX adaptor, and all IC voltages are reading fine (18/9v). There aren't any shorted diodes since the power supply section seems to be reading normally, theres a healthy 9v reading throughout the circuit. I've tried several guitars, humbuckers ect and it sounds like the filter is blended with a dry signal or something, very unpronounced. I got the pedal with the drive switch broken- the black slider tab is missing. I tried patching the fx loop, no success. Where should I start looking? Any help is appreciated!