Did you follow this procedure??? (Is in the manual page 92) Can't turn on the AV receiver
• The amp protection circuit has been activated.
Remove the power cord from the wall outlet immediately.
Disconnect all speaker cables and input sources,
and leave the AV receiver with its power cord disconnected
for 1 hour. After that, reconnect the power cord
and set the volume to maximum. If the AV receiver
stays on, set the volume to minimum, disconnect the
power cord, and reconnect your speakers and input
sources. If the AV receiver turns off when you set the
volume to maximum, disconnect the power cord, and
contact your Onkyo dealer
I also found this to reset AVR... http://www.justanswer.com/questions/...in-my-ht-s6100