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Powerbook G4 Display Issues

3439 Views 13 Replies Latest reply: Feb 18, 2013 1:18 PM by peterlrowley RSS
martin101 Calculating status...
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May 23, 2011 9:03 AM

I have a Powerbook G4 1.67 Ghz that has been having intermittent display problems. The powerbook is running OS 10.5.


The display produces a banding effect that comes and goes - more often than not the monitor is banding.


When the computer is powering up the gray Apple loading screen with the spinning wheel displays fine.  The blue screen right before the desktop appears displays fine.  Once the desktop apears the banding effect begins.  Sometimes it comes and goes.


You can still use the mouse if you can locate the part of the screen you would like to click on.  If I hook up an external monitor to the powerbook - the external display displays fine.


If I startup from the OS Disks - they display works fine.  When I run the hardware test from the CD - it works and displays fine. Hardware test doesn't report problems.


I've linked two photos of the screen. The first photo shows the screen when it not operating properly.  The second photo shows the same screen when working okay.


Bad Screen


Good Screen


Does anybody have any expeience troubleshooting this issue? Any help is appreciated.

  • old comm guy Level 4 Level 4 (2,230 points)
    Currently Being Moderated
    May 23, 2011 11:10 AM (in response to martin101)

    Does the problem show up with a Safe Boot (holding down shift key at start)?


    Just from looking at your picture, it seems consistent with a cable problem between the logic board and the display unit, but the fact that it only shows up when the system is booted is suggestive of something more sinister, which I why I asked about safe boot.


    Does the problem respond to a light rap on the top of the computer near the display hinge?  I am not sure where the cable exits be main box and goes to the display on your machine, so I can't be more specific, though it seems that the display cable comes off the logic board under about the F10 key or so.  The other end of the cable is near the top center of the display, so that would be another area to "thunk" the back of the display to see if that clears up or affects the breakup.

    TiBook G4 1GHz/ G5 2 GHz DP GF Ultra 6800, Mac OS X (10.4.11)
  • Allan Jones Level 7 Level 7 (29,570 points)
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    May 23, 2011 11:38 AM (in response to martin101)

    Martin101 wrote:


    "If I hook up an external monitor to the powerbook - the external display displays fine."


    That's a pretty strong indication of a cable problem. In addition to old comm guy's sage advice, you can watch the image while changing the angle of the display. That usually shows up any potential cable faults and points to the fault being in or near the hinge.


    The head-scratcher for me is why this doesn't happen when you boot from a system disk. Can you use the external monitor to change the desktop resolution of the internal display. If you are in extended desktop mode, you should be able to see settings for both monitors from the external. F7 toggles between mirrored video and extended desktop, as i recall. Does toggling make a difference?

    PowerBook G4 1Ghz 17", Mac OS X (10.4.11)
  • Texas Mac Man Level 8 Level 8 (44,210 points)
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    May 23, 2011 5:45 PM (in response to martin101)

    Some of the display settings are stored in NVRAM.


    Try a PRAM/NVRAM reset.


    Another way to reset NVRAM.


    Restart your mac & immediately depress the Command+Option+O+F keys which will display the Open Firmware screen. Then type the following:

    reset-nvram Then press the Return key & type:

    set-defaults  Then press the Return key & type:

    reset-all Then press the Return key & your Mac will reboot.


     Cheers, Tom



    PM G4 1.25HGz MDD, PB 12" G4 1.5GHz, Mac OS X (10.5.8), (10.4.11, 9.2.2) iSight 
  • old comm guy Level 4 Level 4 (2,230 points)
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    May 24, 2011 7:55 PM (in response to martin101)

    martin101 wrote:


    I'd like to definitively troubleshoot the cause of the problem.   I do have to reset my date and time whenever my battery goes out completely.


    Hmmm.  Sounds familiar.


    TiBook G4 1GHz/ G5 2 GHz DP GF Ultra 6800, Mac OS X (10.4.11)
  • istella Level 1 Level 1 (0 points)
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    Jul 14, 2011 1:15 PM (in response to martin101)

    I have a 1.67 17" with similar but less severe problems.   Almost all of the time, the display - in this case a hi-res A1139 display - has no problems at all; it works fine for hours.  I can, however, make it flicker by opening and almost closing  the display back and forth, in which case I see the display flicker with horizontal lines and criss-cross images.  I've tried all the stuff suggested in this thread, i.e. tapping the back and knocking on the hinges, which does not produce any flicker. Pressing on the keyboard cannot have any effect, since you cannot press hard enough to touch the display cable without bending the upper case.  If my assumptions are correct, i.e. the display is controlled only by the inverter cable and the display cable, then the problem must be with with either of those cables.  In my case, I suspect one of the two cables is getting pinched somewhere around the hinges.  If that is the case, and the suspect cable has been frayed, it is not an easy fix, requiring the display to be taken apart and replacing either of the 2 cables. I will report back if I make any progress. 

  • roddyrod Level 1 Level 1 (0 points)
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    Jul 18, 2011 9:12 AM (in response to istella)

    Thanks for the post.  I guess I was lucky until just recently, where I started having a 1 inch white vertical band facing right side, with my faithful G4 1.67 GHz PB.  I am at the beginning of my search for solutions to this problem.  I am "assuming" that someones solution will help.  Please let us know how it goes.  My PB is well out of warrenty.

  • peterlrowley Calculating status...
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    Feb 18, 2013 1:18 PM (in response to martin101)

    I have a Powerbook G4 with exactly this problem, pretty badly.  Fortunately, I don't have to use it much anymore, but occasionally I do.  The odd thing is that the PRAM reset works for me just fine, but only for about 5 minutes.


    I do have another temporary solution to add to the mix.  Spreading out the fingers of both hands and then applying them in one motion to press (well, sort of slap) on the keyboard as a whole has fixed this immediately at least three times today.  And it seems to be holding... it's been good for over an hour.




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