iMac G4 flat screen GUI streaks

Discussion in 'PowerPC Macs' started by Danny Dorko, May 27, 2006.

  1. Danny Dorko macrumors newbie

    Joined:
    May 27, 2006
    #1
    Can you help me nail this (hardware?) problem?

    iMac G4 1GHz OS X 10.4.6

    As the machine warms up the screen starts to show vertical streaks where windows or graphics refresh or move. If I continue using it, it will crash.

    Under the same circumstances, if I don't use the screen (say, working over Airport) the machine will stay up forever.

    In target disc mode the machine stays up (and the Firewire screen works forever without breaking up).

    The iMac hardware test disc shows no problems (and the test screen works forever).

    It's just the OS X GUI that breaks up and crashes.

    I have scrubbed and reloaded OS X from scratch. The problem persists.

    Any ideas where the fault is?

    Thanks for reading...
     
  2. Benjamindaines macrumors 68030

    Benjamindaines

    Joined:
    Mar 24, 2005
    Location:
    A religiously oppressed state
    #2
    Hmm... This sounds like your graphics card is going bad. I don't know why it only does it under OS X, but my theory is that its something to do with all the other things that work fine (target mode, software test) don't use OpenGL or Core Imaging. If you are still under warrantee I would take the iMac to an Apple store and get it checked out, if you aren't under warrantee then perhaps consider a new machine (repairs will cost more then the iMac is worth).
     
  3. neocell macrumors 65816

    neocell

    Joined:
    May 23, 2005
    Location:
    Great White North
    #3
    Stupid, stupid me :eek:
    Didn't completely read before posting
    please delete
     
  4. mjstew33 macrumors 601

    mjstew33

    Joined:
    May 29, 2005
    Location:
    Illinois
    #4
    I don't think there is anything you can do unless you want to replace the motherboard (where the graphic card relies) :(
     
  5. Danny Dorko thread starter macrumors newbie

    Joined:
    May 27, 2006
    #5
    Thanks Benjamin... it's way out of warranty, but you're confirming my thoughts.

    I was wondering if there might be a DIY fix, because like you say a shop repair is probably uneconomic. But maybe it's curtains.

    No probs Neo, I was baffled when the video tests came up clean. I guess it's intermittent.

    The mother board isn't cheap Stewart?
     
  6. Benjamindaines macrumors 68030

    Benjamindaines

    Joined:
    Mar 24, 2005
    Location:
    A religiously oppressed state
    #6
    One more thing I've thought if is can it work fine with an external display rather then the internal one? And the only logic boards you will find will be on eBay so prices vary, you could get a new one but it's up to you whether you want to deal with eBayers.
     
  7. mjstew33 macrumors 601

    mjstew33

    Joined:
    May 29, 2005
    Location:
    Illinois
    #7
    Nope, not at all.

    It contains the processor, graphics, USB, audio, etc etc and so it's very expensive.

    It's matt, btw. :p
     
  8. Danny Dorko thread starter macrumors newbie

    Joined:
    May 27, 2006
    #8
    Yep, I thought so. Thanks guys... and sorry Matt - you crazy guys with your crazy names, eh?

    :)
     
  9. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #9
    Mmm, but didn't you say that when you boot off a system restore DVD, you see no disturbances in the screen while you're in the test software? That strikes me as strange, if this were a motherboard failure....
     
  10. Danny Dorko thread starter macrumors newbie

    Joined:
    May 27, 2006
    #10
    Not the restore DVD... the iMac H/W Test CD. I didn't know I could boot off the DVD... I might give that a go.

    It does baffle me that the test CD and target disc mode screens are rock solid and it's only a screen with the OS X GUI that breaks up.

    I was wondering about running Unix from the CLI but I think that's in an OS window?
     

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