Novation Ultranova Boot Loop

Hello together, i have a problem with my Ultranova. If i power it up, it shows crab on the Display and reboots. For me it looks like there is a problem with a supplyvoltage… I measured the 3.3V after REG2 and found out, that it goes down to 0,6V when it loops the boot. I tried to power it with 3.3V over a external Vreg, but the problem still exist.

Does anyone know this problem? If it´s the µC i will need a new Board…

If anyone has schematics for me, it would be nice.