Did that,last night shut the rear power switch & unplugged the 970. This morning plugged it back in & started it up, same hiss but now the audio makes a low sounding schreeching & squealing, no discernible sounds such as voices or music. It got much worse over night, sounded like it was going to damage the speakers. Reconnected my 950 that the 970 replaced, exact connections, everything perfect with the 950. Seems like some component was failing & then failed.