Dell D800 Video/Backlight Problems

Hey there Everyone, let me describe this fun little project of mine… I have received a Dell D800 from my school to just play with/repair and it runs fine with an external display connected, but the actual LCD gives me some problems… the computer will run for about 10 minutes and the LCD back light decides it wants to turn off… and it does… i can barely make out that the computer is still displaying stuff… apps continue to run, downloads continue to dl… and such, external monitors work, but the LCD is way too dim for me actually use this, so i was wondering if there are some things i can check before i have to replace the whole LCD panel… any and all input would be appreciated…