Its in protect mode for a reason.Either DC voltage present at the speaker outputs,abnormal power supply voltages detected,failure in the protect circuit.If your familiar with trouble shooting "hot chassis",reading schematic diagrams,using basic testing equipment.Then first verify proper power supply function-Next verify there is no DC volts going to the speaker outputs,this may require making the measurement before the relay.If you detect DC ,start checking for shorted output devices ie. Transistors,Mosfets,hybrid chip amps,etc. If no DC is detected look for a problem with the "protect circuit" possible bad capacitors,transistors and/or chips.
If your not familiar with trobleshooting electronics......Take it to a Pro..:yes: