THanks for the responses. I switched cords, and now I have sound on one channel only. Somewhat bizarre, because it's consistent. Are there any known defects with the beans (this unit was purchased about a year ago)? I'll get some different cords today. I had two amps (Alesis RA 150) die on my so I'm using a home stereo receiver until I can upgrade my monitors.
I'll do some more experimenting today, thanks again.