iMac Freezes

Discussion in 'iMac' started by williemoe, Jan 4, 2013.

  1. macrumors newbie

    Joined:
    Jan 4, 2013
    #1
    iMac 20 inch early 2008
    6 GB ram
    500 GB free space
    The last 3 days the screen has frozen on me for no apparent reason.
    I reinstalled Mtn Lion and it still did it the next day.
    I have run DiskWarrior and Drive Genius - all is well.
    It happens when I step away for a few hours and return to have the computer completely locked up. Have to power off to restart.
    Any suggestions?
     
  2. macrumors regular

    Joined:
    Nov 29, 2007
    #2
    I am having the same issue with my 2008 24". Interested in any feed back you receive.
     
  3. pauldy, Jan 4, 2013
    Last edited: Jan 4, 2013

    macrumors member

    Joined:
    Jun 8, 2007
    #3
    I also have a 24" 2008 iturd with the nvidia 8800gs. I know it's the video card because it's already been replaced twice for the same issue. I don't know why this hasn't turned into a class action lawsuit. Anyone that has used the machines on and off heavily has seen the problem. The last time I was at the store I met two other people with the same problem. The story I eventually got was due to environmental restrictions in the UK nvidia was forced to change the formula in the solder they used for their chips during this time period. The new formula under the stress of repeated hot/cold cycles would form microfisures eventually leading to failed connections in the card. The result was a multitude of failure symptoms all related to the video cards themselves from artifacting, screen blanking and random lockups. Reflowing your card can bring it back but doesn't fix the underlying issue and it will return after time. Some people have reported success replacing with the alternative ati card offering at the time. Also this is not likely the OPs issue as the car din his machine is what people are using to fix their 24" imacs. I would look for clogged air ways in the mac there.
     
  4. macrumors 65816

    Dadioh

    Joined:
    Feb 3, 2010
    Location:
    Canada Eh?
    #4
    I had a 2008 iMac that did this and it turned out to be a bad power supply. Hard to diagnose so try and rule out other things first.

    If you have the installation DVD you could run Apple Hardware Test (AHT) to check for issues.

    It also might be memory. AHT should pick it up if it is.

    Good Luck
     
  5. PBP
    macrumors 6502

    PBP

    Joined:
    May 13, 2011
    #5
    Try this fix. It fixed my 2008 iMac. Also works on the 20" model.
     
  6. thread starter macrumors newbie

    Joined:
    Jan 4, 2013
    #6
    The Kext Helper b7. link doesn't work.
    Can you send an updated link to access the Kext Helper?
    Thanks
     
  7. macrumors regular

    Joined:
    Nov 29, 2007
    #7
    I just today decided to buy a new computer. Hopefully, I'll keep the new one for 7 years instead of 5.
     
  8. PBP
    macrumors 6502

    PBP

    Joined:
    May 13, 2011
    #8
    Download here
     

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