Now, i have ordered the repair part and changed it, with no success. The Error remains.
After Powering On and testeing Rom 0 it says "Problem in System Rom – Bad Checksum". Another thing is, after inserting a library card (in this case alchemy 101) the display reads "your memory card has faulty data. (Bad Checksum). In both cases, after pressing "ok", the unit works and the card reads flawlessly. The System Rom version is 2.158 and Preset roms are V 2.000.
thanks and cheers, tommaso