Onkyo TX-SR705 shuts down suddenly

Onkyo receivers have a safety circuit in them to protect the Amplifier from blowing up:

If you listen closely when it shuts down ( after a loud scene ) there is likely a loud 'Relay Click'..
If this is what is happening you might be able to verify it by turning the volume all the way 'off' and waiting for the circuit ro reset ( releasing the safety relays & returning power to the internal Amplifier ) : you should hear another click, yhen you can bring the volume back up carefully and there will be sound again.

This safety circuit trips when then Onkyo receiver detects an 'Over Current' condition on the
' Power Supply ' that feeds the internal 'Audio Amplifier'..

Generally caused by:

1.
Improper load presented to the Amp outputs ( FL, LR, RL, RR, SUB, CENTER )
If you can ( one at a time ) turn off the SUB, Center, Fronts and Rears: trying to re-create the failure each time while you have one part of your system disabled or having their level turned way down..
You can isolate where the problem is coming from.

- any or all of these speakers being the wrong Impedence ( I.E. 4 Ohms instead of 8 Ohms )
Unless the receiver manual or the sticker near the 'speaker connetor' specifies a range or another value, you should assume 8 Ohms. Your speakers should say on the back of them.

- any of the speakers being connected in parallel ( 2 speakers to a single one speaker output ) .. Two 8 Ohm speakers connected in parallel make a 4 Ohm load to the amplifier.

- If the Suwoofer is Passive ( Not having its own power cord and amplifer ) it has a
Passive Crossover : this crossover can have its own power rating or limitation.. If it is constructed with capacitors that have too low of a working voltage, then they can saturate and the crossover itself can present a load to the amplifier that will case this 'Over Current Shut-Down'..


You user manual should detail this.

Ed