My Yamaha HTR-5740 remote control (RAV250) will operate everything except the volume/mute. The red LED on the remote doesn't even light up when pushing volume +, -, or mute. I couldn't find anything in the manual to explain it but I'm thinking there must be a mode that re-assigns the volume & mute to another device instead of the Yamaha A/V receiver. Is anyone familiar with this model that knows how to assign the remote back to the receiver? I have my Dishnet universal remote set to operate it now but I sure would like to have the original Yamaha RAV250 also control it like it should. I appreciate any help...