Sorry you are having trouble. My guess is that is some kind of upgrade related issue. I would suggest that you do a complete reset of the unit (see “Restoring FactoryEffects Presetrs and System Settings:” in the UM). Apologies if this is what you meant by a “total rest”.

Yes, I made a complete reset of the unit as I sad, I have to go down to 3.5 and than up to 5.2 again. After that the unit works again. 

Befor the Timefactor stops the output it shows me sometimes a “C” with a percentage about 70..78 and other counts.

What does that mean ?