I have a Pioneer VSX-532 receiver and the other day while walking back into the living room, it made a loud noise and everything shut off, then the red HDMI light started flashing and it won't turn on. I have already unplugged everything, left it unplugged from the wall for several hours, and plugged it back into a different outlet (as instructed by support). Since it is a couple months out of warranty, Pioneer support said the only thing I can do is replace it or have it professionally fixed and wouldn't go more into anything at all.
How do I get this out of protect mode?
If it made a loud noise and shut down, a major component has blown in the receiver, and there is too high a current draw, This is why the receiver has shut down. You will not be able to get it out of protect mode, until the failed components are identified and replaced.
For that receiver it is not worth it. Pioneer and Onkyo are now totally unwise purchases as you have now found out. They are right on the verge of bankruptcy, of not already over the edge.
One last point, is that I see that receiver is selling on Amazon for $299.95. You really can't make a receiver for that much money. They are much too complex. You would not even get in the front door of any decent service department for that much money with any receiver.
So now unfortunately it will add to the enormous mound of failed electronic components, euphemistically referred to as recycling.