Hi sebale, welcome to Audioholics.
Does it say 'Protection Mode' on the display?
Any other info would help too.
History of the unit?
How was the unit used prior to this problem?
First I would check that receptacle, by plugging something else into it. An outlet tester would be nice, it's a Home Depot item for under $10.
Or, try plugging a different device into that outlet, to see if it works ok.
I'd then plug your AVR3000 into an outlet in another room. If it still shuts off, and has no speakers hooked to it, the unit sounds defective. possibly an output transistor.
How old is it?
Another thought, make certain that there are no loose strands of wire stuck under any of the speaker output lugs. It might be shorting to the case or another lug.
