Sounds like a similar problem I was having with my Pioneer AVR. I chalked mine up to old age (the Pio was around 8 years and had survived several bumpy moves).
The only thing I can suggest is to make sure none of your speaker wires are shorting out, that could cause a protection fault.
The only thing I can suggest is to make sure none of your speaker wires are shorting out, that could cause a protection fault.