I need some help... I've got a Sony Walkman mp3 player, model nwz-a816. When it's plugged in and charging, everything works fine... but when it's not plugged in, the visual display doesn't work at all. Music still plays... and I'm basically stuck listening to the same artist over and over again until the next time I have a chance to plug it in.

Why is this happening, and more importantly, how can I fix this? Can it be fixed?