So, last night I am drinking beer and enjoying the music when the right channel goes quiet. This happened once before, but it was just the speaker cable had disconnected. However, everything was connected, the amp power light is on, and everything appears normal, except there is nothing out the speaker. Anyway, by now I have had to many beers to troubleshoot electronics, so I switch to the multi-channel system. It's nice, but not as nice as the two channel system.
Today I did all the troubleshooting (switch sources, swap cables, etc.), and it appears the right channel amp is bad. That is the bad news. The good news is I put the left channel amp into stereo mode, hooked up the right speaker, and am back in business. That is the good news. The only drawback is now I only have 350w per channel versus 800w per channel.
Now I will find out how hard it is to get this thing repaired. It is a Cambridge-Audio 840W amp, and is around 5 years old. This is the first piece of gear I have had go bad in a long time. I hope it is not the start of a trend.