iMac G4 Display Problem

Discussion in 'Mac Basics and Help' started by Spock, Jan 14, 2007.

  1. Spock macrumors 68000

    Spock

    Joined:
    Jan 6, 2002
    Location:
    Vulcan
    #1
    Ok, I think I have posted this problem once before but did not get any help at all, I have a 15" iMac G4 1ghz when it wakes from sleep or I change the screen res. it destorts and the screen jumps and i must restart. I would really like to figure this out.
     

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  2. Makosuke macrumors 603

    Joined:
    Aug 15, 2001
    Location:
    The Cool Part of CA, USA
    #2
    I assume you're talking about that speckled color "noise" in that photo?

    If so, there are three possible sources of that kind of problem: Software issue, graphics chip issue, or monitor problem.

    If you take a screenshot (Command-shift-3) when it looks funky, does the funkyness show in the screenshot? If so, then the problem is either software or the graphics card. If it does not, it's probably with the screen, which is a bummer since you can't replace it inexpensively.

    Also, have you tried running the Hardware Test disc that came with your computer? It will generally tell you if there's an issue with the graphics chip (which would also be a bummer because you can't replace it without getting a new motherboard).

    If it's a software issue, a reinstall should fix it (and if it doesn't, it's definitely hardware), so that's what I'd hope for if I were you.
     
  3. Spock thread starter macrumors 68000

    Spock

    Joined:
    Jan 6, 2002
    Location:
    Vulcan
    #3
    Hardware Tests check out, screenshot is clear I have also tried the basics zapping the pram, NVRAM nothing. I did not buy this iMac new, when I got it I never even thought this would be that way so I didnt check. The only thing i can really think about and i forgot to mention was the Hard Disk is 160GB if memory serves this iMac model never shipped with a Hard Disk that size so its been replaced, could the swap out damage some thing inside?
     
  4. Reflow macrumors 68000

    Reflow

    Joined:
    Mar 30, 2005
    Location:
    NJ/PHL
    #4
    Do you have any power supplies near the monitor? This can cause the screen to go wavy
     
  5. Spock thread starter macrumors 68000

    Spock

    Joined:
    Jan 6, 2002
    Location:
    Vulcan
    #5
    No, I just have the Pro Speakers and a Wacom graphics tablet on my desk. It seems to get worse the longer its on. After a restart like I said the display is bright, crisp and clear not one dead pixel.
     
  6. Makosuke macrumors 603

    Joined:
    Aug 15, 2001
    Location:
    The Cool Part of CA, USA
    #6
    Probably not, but it is possible; those iMacs have a heatpipe that transfers heat from the main body down into the baseplate for dissipation.

    You need to re-apply thermal grease to the point of contact between the base and the upper half of the dome if you dig around inside, so it's possible if somebody was rooting around in there and forgot to apply the thermal grease when putting it back together (or didn't realize it was necessary), then it could be overheating, which MIGHT have symptoms like that--it would certainly explain why it gets worse the longer it's on.

    If you're not averse to cracking the thing open you could open it up and reapply some thermal grease to that spot and see if it helps the problem. Worst it can do is nothing.
     
  7. Spock thread starter macrumors 68000

    Spock

    Joined:
    Jan 6, 2002
    Location:
    Vulcan
    #7
    I have been thinking about opening her up, I have never done it, but i have pulled G3 iMacs and iBooks apart. I also plan on adding RAM in that upper slot so the take apart wont be wasted.
     
  8. Jiddick ExRex macrumors 65816

    Jiddick ExRex

    Joined:
    May 14, 2006
    Location:
    Roskilde, DK
    #8
    Seeing as a restart fixes the problem, I would rule out hardware issues for now. Have you tried making a new user account and using that? Does the problem reappear? If not, there's your problem.
     
  9. Stridder44 macrumors 68040

    Stridder44

    Joined:
    Mar 24, 2003
    Location:
    California
    #9
    This is a little off topic, but I have a 17" iMac G4 and was wondering what the LCD screens' tech specs were (contrast ratio, etc.)
     
  10. iMeowbot macrumors G3

    iMeowbot

    Joined:
    Aug 30, 2003
    #10
    Details here, left column, near the bottom.
     

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