Hello, My name is Aric and I will be glad to assist you.
I'm sorry to hear about the problems you're having with your Sony.
Hello, This issue comes up very often regarding these systems. "Protect" is an indicator that there are either shorted speaker outputs inside the unit, a shorted speaker wire, or a blown speaker connected to the unit.
Unplug the unit from AC power for 30 minutes, and disconnect all of the speakers and other associated equipment. Upon plugging back in, press and hold the power button at the same time for 5-10 seconds to force a hard reset.
If the unit starts up normally start connecting the speakers one at a time (shutting the power down before connecting each one), until one of the speakers causes the "Protect" indicator to come on. This speaker is faulty and would need to be replaced.
If the unit shows "Protect" with NO speakers connected, then it needs the output transistors replaced inside the unit. They are not user-replaceable as they are PCB mounted, and thermally coupled to a heatsink. In this case, the unit is in need of service.
If this answers your question, please click "Accept". Tips and Bonuses are welcome and appreciated!!