I'm running 10.5.5 and suddenly my optical output stopped working. I have double checked every setting on my receiver and OS. It correctly says digital out in my sound preferences, my receiver works fine, made sure it is set to optical 1. I have connected 2 cables to my mac mini, and macbook pro. Nothing. No audio. But the cable is getting powered, it is lit up red. This worked before, but suddenly stopped? Can someone help!