More than likely, it's not a problem with the receiver. The fastest way to tell is to disconnect all speakers at the back of the receiver and turn it on. If it does not shut down, your receiver is ok and is just protecting itself from damage. If it stays on, check all your wiring, what it sounds like is that you have one or two braids of wire touching the other terminal. Not enough to cause a "short" at turn on, however, when you turn up the volume the resistance increases and creates a short, thus "overload" shows on the receiver. Hope this helps. If you need more help troubleshooting, post a comment and I can help more.