no audio output with jvc dr-mv5s dvd recorder with vcr recorder

Just recently, our JVC DR-MV5S dvd video recorder with vcr recorder will play dvd and vcr but with no audio. I checked connections and setup screens, I checked JVC web site looking for technical support. I found some dvd reset codes on JVC's web site but none related to my model. I tried those reset procedures and none worked. I rebooted/recycled the DVD player at least a dozen times. Any clue on what to try next?
Thanks in advance for your assistance.