Same problem overhere, but managed to figure out some more ... Ours is shutting down, only when "cold".
With key-combination "Adv Surround" + "Power-On", it resets it's processor, and it keeps going, even when I shut the receiver down, and back up again some hours later, it goes on without any problem.
Over-night, we always have the same issue. Receiver shuts down again after 3 seconds.
I put the receiver outside where it is cold. No go, does not want to power on, even with the key-combination described above. Shuts down again !
Did de-assembly of the end-trap of the amp, and put that board in a 60 degrees forced-air oven.
Put that board back into the very cold amp, and ... It started right up !!!
Must be a component (I think an RTC) that is failing !!!!
Any ideas ?