mid 2011 iMac pixellates, then screen freezes

Discussion in 'iMac' started by kindwaryr, Feb 24, 2016.

  1. kindwaryr macrumors newbie

    Joined:
    Oct 22, 2014
    #1
    This has been an occasional problem with blinking random pixels, but it has escalated into freezing the screen and making it impossible to use the iMac without a cold reboot. I know of the video card recall for this model, but when I took it in and it was tested, it didn't fail the video test and was not eligible. Running latest version of El Capitan, added SSD as new boot disk a few months ago without incident. Have done extensive research online but nothing seems to help.
     
  2. magdale macrumors newbie

    magdale

    Joined:
    Feb 26, 2016
    Location:
    Italy
    #2
    Hi kindwaryr! I have the same problem with my iMac 27 "mid 2011 HD 6970M 2GB video card. After seeing several videos on youtube I'm pretty sure the problem is the video card. In addition to the problems described by you, to me often the monitor It has the brightness dips. it's like flashes and then returns to his place.
    I'm out of Apple's program to replace it. At this point I would like to try the reball and change the BGA chip.
    I really hope to solve this problem!
     
  3. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #3
    It very likely is the video card but unfortunately if it's intermittent and just so happens that it doesn't fail when Apple tests it, you're out of luck. If you have an external monitor that you can test with, keep it hooked up to your iMac so that when the video acts up you can see if it affects the external monitor or not. That way you'll know for sure.
     
  4. magdale macrumors newbie

    magdale

    Joined:
    Feb 26, 2016
    Location:
    Italy
    #4
    Do you know wich chip I have to buy if It's a video card problem? I have seen 216-0811000 on aliexpress.
     
  5. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #5
    If the program is still in force, take it back.

    I had a 2012 rMBP that had a GPU issue. It wouldn't act up in the store but they looked through crash logs and found GPU related ones and OK'd the repair.

    If the warranty os over, things get trickier. If your iMac has an MXM GPU you may be able to just replace it. There is a thread on this very board about replacing the MXm GPU in 2011 iMacs.
     
  6. magdale macrumors newbie

    magdale

    Joined:
    Feb 26, 2016
    Location:
    Italy
    #6
    I called Apple and they say that my iMac is among those defective but they can not fix it because it's been more than 4 years of purchase :-(
     

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