MXR M80 suddenly distorting all output, even when bypassed

[poit57]

My M80 pedal is distorting all output from both the XLR and 1/4 inch outputs. Does anyone have any suggestions as to what could be happening?

I always power the M80 with phantom power from the board, and it worked well when I took it to church camp a few weeks ago. It has been sitting in my gig bag since then until I took it to my church a couple days ago.

When I connected the M80 to the board at church to check levels, there was no output, but the channel would pop if I clicked the effects button on and off. I connected a 9V power supply and disengaged the phantom/ground switch, but still no output until I plugged a 1/4 inch cable into the parallel output, and suddenly the XLR output started sending a signal. That signal was terrible and picking up local radio.

I took the pedal back home and tried it with phantom power, 9v power supply, and a battery. No matter the power source, the signal is distorted, whether the preamp is bypassed or engaged. It sounds like the input of the M80 is being clipped. It has the same distortion if I try playing a passive electric guitar at low volume through the pedal.

 

[Old Garage-Bander]

Hopefully when you use phantom power, or other external supply, it isolates from the 9V. If not, and the 9V is bad it could drag down the supply. I know you changed 9V, are you 100% that the replacement batt was good? Just taking a "new" battery, that you may have just purchased, out of the packaging is no guarantee. Try another known good 9V sourced from somewhere else to be sure.

Is the phantom power at the console turned on? Some boards have a master Ph. Pwr switch, others have individual switches for each input. Also try a different XLR cable carrying the Ph. Pwr. Plug the XLR into a different console input.