I just bought a second hand MF-102, it worked fine, i had my Wurlitzer 200a going through it and decided to see what would happen if i put the phones out to the carrier in of the pedal. it sounded cool, then i unplugged the carrier in and it went back to normal. then i did the same thing again, and now the pedal stopped working. the mix nob when at 12 o’clock there is no volume, at 0 and max there is volume but no ring mod. you can hear a little at max. but nothing is working. any suggestions? anyone know how to troubleshoot these thing?
I have the same problem 
Make sure the knob for LFO amount up on the left is at zero; fully counterclockwise. Does it work now?