OK - here's the issue (you can find it on several other posts): M5 won't boot, rapidly switches on and off, often reboots when you step on it, often people send it back with no solution, etc.

Mine started acting up almost immediately and the problem is intermittent - I've gotten no real response from anyone, and now it's out of warrenty - SO I TOOK IT APART.

I am a trained electronics technician and here's what I believe is wrong with it - it's a relatively easy fix, I believe it's a grounding issue. This is what I've done and it now appears to be working:

1. Remove the 4 rubber feet and their screws. Also remove the countersunk screw on the side holding the MIDI port.

2. Go to a hardware store and get new UNPAINTED replacements - throw the rubber feet away along with all the painted screws.

3. Take sandpaper or a file or a knife and either scrape or sand away the paint from all wholes underneath where the screws will touch. I used a knife to scrape away and a drill bit held in my hand to shine up the surfaces. Those who are more intrepid might want to take the entire back off and shine up the surfaces where the grounding lugs touch the chassis. Do not get filings into the circuit board.

4. Snug up all screws with the new unpainted screw making sure all screws are now making metal to metal contacts.

I believe the power supply is grounded through the chassis. Stepping on the pedal squishes the rubber feet breaking the contact of the circuit board studs to the chassis. Good luck. Mine now works.