4 Replies Latest reply: May 8, 2006 9:15 PM by ccsccs7
Zgreen Level 1 Level 1 (0 points)
So I've read a number of posts thus far in regards to the backlight failing... my situation seems similar. I've had my powerbook for about 3 years now, and I've never had any problems with the monitor. All my software is up to date. This morning the screen was functioning fine, and the computer was plugged into the adapter. I closed it and put it to sleep, slipped it in my bag—as I have done countless times—and when I removed it a few hours later the backlight would not turn on. The computer woke up from sleep, and in direct light I could see the desktop, screen images, etc. Adusting the brightness meter had no effect, either with the F1 and F2 keys or in system preferences. I tried turning off and letting it cool, removing the battery, resetting the airport card, resetting the PRAM, and resetting the power manager (in separate instances). None of this has had any effect. It makes no difference whether I am plugged in or not.
All of this leads me to believe this is a hardware problem, as I saw some posts referring to problem cables that had to be replaced. Just wondering if there were any other theories out there, or if this was a design problem that Apple recognizes. Thanks.

12-Inch PowerBook 867mhz, Mac OS X (10.4.5)
  • 1. Re: Backlight Does Not Turn On
    Josh T Level 1 Level 1 (70 points)
    If your computer was an iBook rather than a powerbook the cause would undoubtably be a part called the Reed Switch, whose cable often gets cut inside the display hinge.

    Since it is a powerbook I'm really not sure. I've not seen that issue in a powerbook though I think it might possibly be the inverter board. You should take it to an AASP and let them take a look as the problem is definitely hardware and not software.
  • 2. Re: Backlight Does Not Turn On
    Jason Sykes1 Level 1 Level 1 (60 points)

    I have the same pwrbk (12" 867MHz) and recently have been having a similar problem. If it goes to sleep, the screen will not come back on when woken up, but I can see the computer is running on the black screen. However, mine seems to be fine after I restart it by holding the power key for 5 seconds, then restarting. Back light will come back on if I 'put' it to sleep and wake it up again, but not if it goes to sleep on it's own. Sorry this is not much help, but may point to a software problem rather than hardware.
  • 3. Re: Backlight Does Not Turn On
    bty Level 1 Level 1 (0 points)
    i am having a similar problem. when my powerbook starts up, the backlight is on...however once the "apple" appears during startup, the backlight turns off. i can still see - faintly - the desktop, but can only use my laptop when its connected to an external monitor.

    i've tried reseting my pram...and pmu....and nothing seems to work.

    could it be software related? i just updated to the latest version of the system - 10.4.6

    i've had my machine for over 3 yrs...

    anyone have any ideas?


    powerbook g4 12"   Mac OS X (10.4.6)  
  • 4. Re: Backlight Does Not Turn On
    ccsccs7 Level 4 Level 4 (1,555 points)
    Sounds like software related. Maybe it's confused about what hardware it's running on.