I have a similar problem. Optical audio out from my c8000 to my home theater system (and old spare receiver) does not work. I switch to external speakers and no audio at all from any sources, hdmi, red/white, streaming from TV, ect. Whenever I have used a piece of equipment with optical audio out active there is a red signal light coming out of the other end of the fiber cable, this has never happened with my tv. I already had my mainboard replaced for a power problem and the old board had the same problem. Am I doing something wrong???
I switched the setup of my system recently from component to hdmi and I can't get the audio to work. I have hdmi from my cable and ps3 running to my TV then digital audio from my TV to my reciever. I have the internal mute on the tv and still no sound. I can get the auxilary audio to work but not the digital audio. Any help would be great!