Sony Stereo Receiver - STR-DE425 Loud pop and "PROTECT" Flashes. When I turn it on and off several times it finally stops. What do I need to do to find out what the problem is? This happens about 80% of the time when I initally turn on my TV.

Toggling power on and off is NOT a good idea, nor does it ever really fix anything.

Does the TV affect the receiver even if you have other sources selected or speakers disabled?

Establish if the TV connection or lack of it affects the problem by disconnecting one cable at a time (I have no idea what cables you use) to see if the self-protection is caused when the TV is turned On. Prove that each cable is or is not involved with glitching the receiver. If it still pops after the TV is completely floated from the receiver, consider a power surge as the culprit. Maybe you need to place the receiver on a power circuit that isn't shared with the TV.

Oh, btw, you're not drawing power from the convenience outlets on the reciver for anything that sucks up a lot of juice, are you?