hitachi 51g500a help please!!?

Watching my Hitachi 51G500A and suddenly the screen went blank. Had audio, but no picture. Turned if off, back on, and still no picture. The audio is great though! I understand this model does not have a lamp. The set is 8 yr old.
Can't seen to find any help for this...anyone with an idea, or if it is worth fixing? Also, I need a schlematic for this set.
Thanks in advance