Sorry to hear of your woes. To what extent has your G68 stopped working?

Do you get the display menu?
Does the Config program recognise the presence of your G68?
Can you get into get calibration wizard and if so, can it play the test tones?
Have you tried a reset? (page 26 of the manual)

Main system - Sources (Kodi-HTPC, Vero 4k, FireTV, Sat) into Trinnov Altitude 32 (8-16) (+Roon), Trinnov Amplitude 8 amp & Vivid Audio (Giya G3, V1.5) and REL Stentor III speakers. Others: F80 + Raspberry Pi and other Pi systems.