QUestion on intermittant audio dropouts

Bob, again thanks for the assistance. I was unfamiliar with optical ports and optical cable. My Panasonic plasma set uses an HDMI connection from the Comcast HDTV digital cable box for combined video and audio. I wonder if I could bypass the internal audio system by connecting to the analogue (RCA) audio out to external speakers and see if that would be a cure? Not sure how that would work with the HDMI connection still in use and necessary for video.

Would appreciate your thoughts.