Onkyo 705 Troubleshooting

Hello all;

I have a problem with my Onkyo 705. In a nutshell, it shuts down when I am watching a movie and have the volume higher than around -24, -25 Db. At first I thought there was a problem with the amplifier so I tried to reset the receiver by leaving it unplugged for a night. That didn't solve the problem. Then today I was attempting to adjust the levels of the rear speakers. I went to the speaker setup menu, level calibration and cycled through the speakers to independently adjust the levels. Each speaker worked fine until I got to the Surround Right speaker....the receiver shut off. I disconnected the speaker and tried again.....shut off again. Each time I select the Surround Right speaker, the receiver shuts off. Every other channel works great.

Is there anyone who has suffered from this problem? Is there anyone who has not suffered from this problem but has a solution for me? Any help is appreciated. I am trying all I can to avoid sending this monster to a service center....it's expensive to send a 30 pound hunk of metal in the mail.

Thanks