I have a Sony STR-535 stereo receiver. In the middle of a song, the audio clicked off and now the display flashes "Protector." None of the buttons respond. Is my receiver totally broken? Or is there a simple way I can fix it, like a combination of buttons? Any help would be greatly appreciated. Thanks.
Not familiar with your specific model, but the following applies to stereos in general:
The speaker protection circuit was activated. It is designed to disconnect power from the speakers to spare the speaker coils from seeing DC. Disconnect the speakers and see if it does the same thing -- turn the volume all the way down before powering it up with speakers removed. If it does, read on. If it doesn't, bingo, bad speaker.
Unless you're one of the rare cases where there is a reset button on the rear of the receiver and resetting fixes it -- I have "repaired" certain stereos and vcr's simply by resetting a glitch condition -- you are likely facing blown/shorted outputs. Not recommended as a DIY repair, as there are usually multiple driver stage transistors, among other components, which fail in addition to the final outputs. Each one must be tracked down and replaced to avoid blowing the new, costly outputs.