I have a Sega CD model 1 which emits sound through the right channel only any time the PCM is used. Redbook CD sound is fine and goes through both channels, same with Genesis sound. It doesn't matter if I use the mixing cable or send all of the Sega-CD's audio through the Genesis, the result is the same. I assume there is likely a dead cap perhaps, but which one? I don't have a reliable way of testing caps with my multimeter.