iMac G5: Capacitators or GPU?

Discussion in 'PowerPC Macs' started by jpcoelho, Apr 12, 2013.

  1. macrumors member

    jpcoelho

    Joined:
    Jan 11, 2013
    Location:
    Aveiro, Portugal
    #1
    Hello!

    I have a 1st generation iMac G5 (17 inch, 1.8 GHz) which does not boot up...

    it chimes, the gey screen with Apple logo appears (with artifacts) and it freezes before completely loading the OS... I have reviewed some of the threads regarding iMac G5 issues, but none seem to describe this issue completely... I understand that common causes are either the caps or the GPU, just wanted to check if someone has had these exact symptoms and what the cause was...
    here are some stills of what the boot screen looked like:
    [​IMG]
    [​IMG]
    [​IMG]

    thanks in advance...
     
  2. macrumors 6502a

    rjcalifornia

    Joined:
    Oct 4, 2012
    Location:
    El Salvador
    #2
    Bad Hard Drive? System error?
     
  3. macrumors 68000

    MisterKeeks

    Joined:
    Nov 15, 2012
    #3
    Doesn't sound like either of those.
     
  4. macrumors 601

    eawmp1

    Joined:
    Feb 19, 2008
    Location:
    FL
    #4
    Open it up. It was easy to do on this iMac. You can visually examine the capacitors (they bulge out if bad) but my money is on the GPU. Can you boot off a system disk?
     
  5. thread starter macrumors member

    jpcoelho

    Joined:
    Jan 11, 2013
    Location:
    Aveiro, Portugal
    #5
    Thank you all for the input!

    You are right, the boot disk was actually my powerbook in target disk mode... the question mark folder appears, it then recognizes the powerbook drive and starts to boot, until it freezes...

    I did open it up to examine the caps, but found no obvious culprit... there is one questionable cap that may be somewhat bulged, one of the four 1000uf 16v caps.

    I may try to change this cap first, to see if that fixes it... if not it will probably be the GPU, or is there some alternative cause I am missing?
     
  6. macrumors 68040

    Joined:
    Jul 11, 2009
    #6
    If you're in there, change all the caps. If one is bad, the others are from the same batch and will likely follow. What you're seeing on screen looks like what I saw on another old G5 iMac when the caps went.
     
  7. thread starter macrumors member

    jpcoelho

    Joined:
    Jan 11, 2013
    Location:
    Aveiro, Portugal
    #7
    Ok, good to know... hopefully it will be just the caps, I don't really want to have a go at the GPU with the heat gun!
     
  8. macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #8
    More likely it's the GPU.
     
  9. macrumors 68040

    AlphaDogg

    Joined:
    May 20, 2010
    Location:
    Boulder, CO
    #9
    Lol capacitators
     
  10. macrumors 68000

    Nameci

    Joined:
    Oct 29, 2010
    Location:
    The Philippines...
    #10
    I had that same thing happened to my quad.

    The culprit, memory. I have to open up my quad G5, remove all the dust bunnies and reseat all the memory sticks.

    Hth.
     
  11. thread starter macrumors member

    jpcoelho

    Joined:
    Jan 11, 2013
    Location:
    Aveiro, Portugal
    #11
    Thank you all for the input...

    I will therefore tackle this one from the easiest solution to the hardest:
    1- check the RAM modules (thought I believe they are both working properly)
    2 - replace Logic Board Capacitators
    3 - if nothing else works, try to reflow the GPU with a heat gun
    4 - if not even that works, see if one of these may work and make it an iScreen ;)

    cheers!
     
  12. macrumors newbie

    vrodion

    Joined:
    May 15, 2012
    Location:
    Canada
    #12
    GPU ! my G5 has the same issue
    replaced all capacitors, bur stil the same nvidia issue
    tried to re-heat gpu- dont work
     
  13. macrumors 6502a

    PowerPCMacMan

    Joined:
    Jul 17, 2012
    Location:
    PowerPC land
    #13
    I would have to say...

    GPU for sure.. sounds like the iMac is overheating or there is the possibility of your capacitors leaking onto the GPU chip which could be causing this.. or if not that, then the GPU is starting to go up and the only way to fix that is a new logic board..

    At that point you can decide if its worth it.. Personally, the iMac G5's had so many problems that many just replaced them with Intel iMacs.

    Here are some sources for replacement Logic Boards:

    www.applecomponents.com
    www.hardcoremac.com
    www.macpartsonline.com
    www.mac-pro.com

    Good Luck..
     

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