Original post by: Bradley ,
The most likely cause it the logic board, which is the driver for the backlight. There is one particular part that tends to blow. So a new logic board would most likely be necessary. There is a slight chance that it is the display, but most likely not. If it is the logic board and you replace the display, your new display could be fried by the logic board. But I'm quite sure it is the logic board. A new one will run you about $400, and is a moderate repair for a non-technical person.