1 Reply Latest reply: Jun 2, 2009 7:01 PM by louie
Chris Caudle Level 1 Level 1 (0 points)
I've seen several other topics about screen flickering but none are like what I'm experiencing.

A few days ago when my Powerbook woke from sleep, the screen began flashing between the normal display and black. Increasing the brightness of the screen makes it flicker faster, decreasing the brightness makes the flicker slower (2-3 seconds between black flashes). Decreasing the screen brightness to the last dot results in the screen functioning normally, although on its dimmest setting. After some time, the screen brightness can be increased a couple of dots without incident, but go too far and it flashes again.

No idea what would make it do this other than some kind of connection problem to the screen's power source, maybe some kind of logic board issue. If anyone has seen this or knows what must be done to fix it, please let me know. Thanks.
  • louie Level 4 Level 4 (2,945 points)
    I will make an educated guess and say it may be a bad inverter and/or backlight tubes. The inverter is a small circuit board that converts the low voltage into the high voltage needed by the fluorescent tubes in the backlight assembly. IIRC, neither is easy or cheap to fix. The iFixit guide just shows replacing the entire screen assembly, which includes all of these parts. This problem is also hard to test without replacement, but you might consider connecting an external display to make sure this isn't a video drive problem.