Pioneer head unit, help!!!

I just bought a car off a guy and he had a Pioneer DEH-P7300 head unit installed in it a little while ago. The display screen stopped working but he didn't give me any details as to what happened. The cd player still works fine and all the buttons seem to be working. What I was wondering was maybe there is a blackout mode for the display that he could have accidently activated? Does anyone know if the pioneer headunits have a blackout mode and if so how do I deactivate it? If no black out mode could it be a bad connection or is it most likely that the display screen has burned out? I wasn't able to download the instruction manual off the pioneer website so I would greatly appreciate any help.