Please post model number. That help us know what the audio menu selections are. What sre his setting setup up for. THX,Stereo,and....... Try setting all of the setups the same as the good ones. Go thru the audio menus of the working setup (write it down) then setup the bad channels and set them up the same way as the good ones. See if that does it. Does it have PCM setup?
engtaz