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Q: Powerbook G4 screen is blank but backlight still works?

Left my Powerbook open, on and unplugged a week ago which obviously caused to the sleep and eventually drained the battery.  Now when I try to turn it on, I hear the chime, hear the hard drive run but the screen remains blank.  After a couple minutes though, the screen will flash half white and you can see the backlight turn on from the keyboard and corners of the screen.  I can change the brightness, change the volume, everything - the screen will just not display any video.  Took it to the Apple store and they said it was either a bad video card or the screen was damaged.  Within the past couple years,  I have replaced the screen, the hard drive, the ram, and the battery - all to prolong the life of my powerbook.  I've opened it up and checked the logic board to look for a pinched cable or any sort of damage and nothing.  I've taken off the bezel and checked for the same and nothing.  Apple says they do not supply parts for computers that are older than 5 years so I'm kind of screwed there.  Does anyone have any suggestions?  Thanks

PowerBook, iOS 4.2.7, PowerPC

Posted on Jun 27, 2011 8:46 PM

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Q: Powerbook G4 screen is blank but backlight still works?

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  • by old comm guy,

    old comm guy old comm guy Jun 27, 2011 11:59 PM in response to plane928
    Level 4 (2,244 points)
    Jun 27, 2011 11:59 PM in response to plane928

    Give this a try: leave the machine turned off but on the power adapter.  Remove the main battery and leave it overnight on the power adapter, in order to charge the backup battery.  Although the backup battery might by now be pretty much tanked, you might be lucky and have some juice in it in the morning.  Then put the main battery back in, power the machine and see what happens.

     

    That being said, it may be that the backup battery is pretty useless by now, since the useful life of the Li-Ion backup cells is on the order of five or six years.  That particular symptom you describe is one that will show up if there is a backup battery problem.

     

    One other thought is that often, when the backup battery is weak, a PRAM reset at boot will get you going again.  (Hold down cmd-option-P-R key combination at boot until you hear the second boot tone.)  You should try this right away, then go to the overnight charge if it doesn't help, then do the PRAM reset when you put the main battery back in and boot the computer.