iMac G5 Screen Issue (Green pixels)

Discussion in 'PowerPC Macs' started by winterdude010, May 3, 2010.

  1. winterdude010 macrumors regular

    winterdude010

    Joined:
    Feb 24, 2006
    Location:
    New York
    #1
    In the last week the screen on my iMac G5 has been displaying green dots all over the place. I know the issue is not with the screen itself because I was able to capture the pixels with the Grab program taking a screenshot (posted below). What could be causing this? The graphics card or something else? Thanks!

    [​IMG]

    EDIT: So just thought about this...you probably won't see pixels in the picture on your screen, I just do on mine. Anyways, the screen gets progressively worse over time and now there are both green and purple lines of pixels all over the screen distorting words and pictures.
     
  2. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #2
    It's known problem in some G5 iMacs and first series of Intel iMacs.
    Your LCD is faulty.If it was graphics chip, that lines should be visible on the screenshot too.
    You can replace LCD or use external display


    Edited: now i see these dots thanks to MacHamster's post. Seems to be graphic card's fault/overheating. Try do clean dust from your iMac first.
     
  3. MacHamster68 macrumors 68040

    MacHamster68

    Joined:
    Sep 17, 2009
    #3
    there are green dots visble on the screenshot

    some one the left side around the rear wing of red car all the way towards that bush and on the right side
    from the grill of the red car all the way up to spotlight , the dock is full with green dots too,but the safari window surprisingly is dot free , at least i could not see one or missed one
    try changing the background picture maybe a solid color one several times and watch for dots or no dots
    , so i guess its not your lcd screen , i guess its a graphic card issue , and as its a iMac g5
    i would open it clean it and look for bulging capacitors , as the pre isight 1.6, 1.8 and 2.0 are known for bad caps which can effect the graphics card :(
     
  4. DSPalpatine macrumors member

    Joined:
    Nov 9, 2009
    #4
    I think MacHam got it right- most likely a graphics card issue. Open it to check for bulging caps, but also blow out all of the dust you can find, especially around the graphics card. I have seen too much dust cause these machines' graphics cards to act funny- sometimes cleaning them out can help.

    If not, be prepared to bite the bullet and get a new machine. If you are handy with a solder, you can try to replace the bad caps if that is the problem, but at this point, you might be fixing one problem only to have something else go wrong in a month... or a week... and you'd be trying to keep alive a computer that is part of an end-of-the-road platform (PPC).

    And rather than waiting for it to die, it might make sense to replace it while the machine still works and you can transfer your data safely to a new machine.

    I'm going through the same thinking with my G5 iMac. I've kept it for far longer than I anticipated (in part a sentimental decision, as it was the machine that brought me back to Apple after fifteen years of wandering in the wilderness of Windows), and it has provided great service, happily running Leopard, and serving as the family computer in the den. Still, it's starting to have a few intermittent issues, and I'll probably replace it with a Mac Mini and a 3rd party monitor. Something to consider, if you can afford to replace it.
     
  5. MacHamster68 macrumors 68040

    MacHamster68

    Joined:
    Sep 17, 2009
    #5
    if it has bad caps and if you know someone or are yourself good with a soldering iron
    the bad caps cost about £20 (sets are available sometimes on ebay or some apple repair shops), even giving a local radio repair guy a chance to solder them in might set you only back £50 and your iMac would be ready for work again
     
  6. winterdude010 thread starter macrumors regular

    winterdude010

    Joined:
    Feb 24, 2006
    Location:
    New York
    #6
    Hello, thanks for the replies. I opened up the computer and all of the caps were fine. And there was very little dust in the machine. So I'm not quite sure what would be causing the issue now. The pixels appear as soon as I log in now and get progressively worse (I'd assume worse as the temp of the computer rises). The only odd thing I found were these green spots on the edge of the G5 area. I attached a picture, not sure what that would have come from but it doesn't seem to me that it's a normal occurrence.
     

    Attached Files:

  7. MacHamster68 macrumors 68040

    MacHamster68

    Joined:
    Sep 17, 2009
    #7
    at least theses caps in the picture are fine , the green spots on the copper is oxidation , so i guess it was standing around in a humid environment for quiet a while or someone was washing it and water got inside ..which could explain something eventually water and electricity do not mix well on a logic board

    but your graphics card is on its last legs i suppose , might last like that for a while or goes tomorrow , and as far as i know the graphic card is not replacable as its part of the logic board and a used refurbished logic board cost quiet a bit , dont even know if apple still has them new in stock, but certainly not cheap :(

    but there is light at the end of the tunnel it might be worth to look ebay for same one with a broken screen or so ..if you dont have the money ready for a new Mac

    but i would try to get a used mini and a monitor ...it might be cheaper too
     
  8. winterdude010 thread starter macrumors regular

    winterdude010

    Joined:
    Feb 24, 2006
    Location:
    New York
    #8
    Well where I live it's extremely humid in the spring/summer especially being that the computer is upstairs where it's warmer. So that would probably account for the oxidation. Thank you very much for all of your help! Everything is backed up on Time Machine so I'll see how things go and see how long of life I can get out of this until buying a new mac. I can just use the hunk of junk PC for a little if this one goes. But thank you once again!
     

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