STF8300 download only fully white images

Dear support I am from Italy
My SFT8300 seem to work perfectly, it is recognized by software (setup does not fail), temperature control works, if i set 1 second exposure i see shutter work, i see downloading image, but image is full white (value of 65534 ) fully even. Obviusely with the cup, or in the dark.
Several month ago it was working perfectly with same PC (windows 10 pro).
I try to:
change the cable --> same result
PC reboot several times --> same result
SBIG driver and firmware update --> same result
Downloaded image is fully white end fully even (no noise, no gradient as typically dark frame have)
Camera body has any kind of damage!
Also control of color well run!
What can i do?
Service center in Italy or CE countries?
Ciao
Paolo Formenti