I HAVE A HARMON KARDON. I HAVE A HARMON KARDON AVR 310 RECEIVER. I HAVE NOT USED IT IN ALMOST A

Question

I HAVE A HARMON KARDON AVR 310 RECEIVER. I HAVE NOT USED IT IN ALMOST A YEAR BUT I REMEMBER IT BEING COMPLICATED TO USE. I WENT TO USE IT YESTERDAY, AND IT POWERS UP FINE, BUT WHEN YOU TRY TO PLAY SOMETHING THROUGH IT, THE ONLY TIME YOU HEAR ANYTHING IS WHILE YOU ARE TURNING THE VOLUME k**b. IF I TURN THE VOLUME k**b BACK AND FORTH, YOU WILL HEAR SOUND, BUT AS SOON AS YOU STOP TURNING THE k**b, THERE IS NO SOUND AT ALL. I ALSO THINK IT USED TO LIGHT UP ON THE LEFT SIDE SHOWING THE SURROUND MODE IT IS IN, AND THAT ISN'T LIGHTING UP. THANKS, MARK.