I bought a used M13 from an auction site that doesn't guarantee functionality, based on my research showing very few issues with these. Using a Line 6 PX-2G power supply, when the unit powers on random panels light up, blank, with random colors, and no switches or knobs do anything. When I switch it off, wait, and back on, typically a different set of panels/colors lights up.The pedal had this failure mode when I got it, but suddenly DID work fine for 3 days, and currently is back to the random panel lighting. I opened it up, re-seated the ribbon cables, and had a look around and found nothing that looked obviously broken/burnt. Anyone else had any problems like this? Any experience with Line 6 repair service?