its ur screen, happens with macbooks coming of age
none of the macbook non unibodys were led backlight. They were all CCFL.
White Macbook Unibody and the aluminium unibody are LED backlight.
Sorry, ill have to rephrase myself.
"Happens with all macbook NON unibodies coming of age."
Could only be an inverter or possibly another fault (damaged inverter cable or logic board) if the backlight fails to come on or backlight flickers NOT if you have partial backlight.
In this instance the inverter is doing its job correctly but its the CCFL lamp at the top which is failing to power on thats causing the top areas to become dimmer.
By all means justperry could be right but hey what do i know, im a newbie.