Hi, I recently purchased a beat up D6. It looks like it was dropped from the headphones jack side. It didn't work with batteries. I opened the device and it looks like someone tried to repair the red jack where line in and mic goes. I found a cracked trace and now the batteries work again. I removed the mute module and still the same issue. Dolby NR is working. When I try to listen from the "Line Out" sound it's almost cero to none. When I connect input to the line in or mic. sound it's only on the left side? Thanks!!
Without knowing your skill level, I always clean the switches with DeOxit and it fixes a lot of similar problems. Headphone jacks take a lot of abuse, both corrosion on the female internals and loose wires from years of pushing the jack in and out, make sure they have a connection. It could be several different problems, look at the wires around the play head, maybe try taping something and play it on another machine to see if it's stereo.