Mailist to discuss all issues regarding the Digitech GSP-2101 Guitar FX Processor

Hello group,
this is my first post since I joined the community. First of all, I
must excuse about my English because is not my mother language (I'm
from Spain).

I purchased a second hand GSP-2101 some months ago from guy in a local
guitar gear forum. I received the unit without the top cover, with no
tubes and the tube retainers where missing. Except that, the unit is
functional, but it "locks" randomly when changing presets using the
wheel, entering / exiting the tuner, sending midi controls or storing
changes to memory. These locks only affect to the control chip, the
unit doesn't react at any button (except power, of course) but the
preamp and the algorithm keep working. Sometimes, after the hang up
the unit will not power up correctly, showing strange characters in
the screen after boot up, but turning off and waiting some minutes
makes rid of this problem.

Any clue of what makes this strange behaviour?

Regards,
Nestor.