The Onkyo protection circuit is activated when the sensor in the receiver detects excessive heat or voltage irregularities. Using speakers with the incorrect impedance and running the receiver at excessive volumes for a prolonged period will trigger the protection circuit. When the device goes into protect mode, the unit will shut down, and the standby light will blink continually. This prevents the fuse from blowing. If your fuse were to blow and the device continued to run the amp could become damaged.
Unplug the receiver's power cord from the wall and leave unplugged for at least one hour. Remove all speaker and audio cables from the back of the receiver while waiting.
Reconnect the power cord after at least one hour has passed. Leave the speaker and audio cables disconnected.
Turn the receiver on and turn the volume to the maximum setting. Leave the receiver on for 30 seconds. If the receiver shuts off and goes back into protect mode you will need to contact your Onkyo dealer.
Turn the volume back to the minimum setting and turn off the receiver.
Unplug the power cord from the wall and then reconnect the speaker and audio cables.
Plug the power cord back in and then power then turn on the receiver.