I have an Onkyo TXNR801, and its hooked up through my computer. I just use the standard audio out to the video 1 audio input. Everything was working great, I could turn it up loud as hell and it was fine, then a couple days ago it would just shut off when it got to about 65. Hardly loud. Any ideas of what it could be? Its still under warranty, but the local service place said it will be two weeks to repair. If its something simple like a fuse or something. id like to do it myself. Any ideas? Another thing, im not using the crossover in the sub like Polk Audio suggests. Could that anything to do with it?