Original post by: originalmachead ,
''This seems to be a '''"known issue" '''as they say in the Mac World.'' Could be the LED Backlight Board or the PSU. Since there's been quite a bit of chatter about this I would go to [http://www.apple.com/support/contact/|Apple Support] and s''ee if the machine in questoin is still under warranty, if not, there may have been '''a silent recall, extended warranty or coverage still in effect''' on your machine.'' If there doesn't seem to be, I would contact Apple directly and rais a bit of fuss- as there's quit a bit of this on the [https://discussions.apple.com/thread/3022651?tstart=0|Discussion Board] and other Mac Forums. ''If this Answer is helpful '''please remember to return and mark it''' Accepted.''