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3gs LS Level 1 Level 1

Hi all,


Does anyone know if Apple addressed this problem? I still get random flickering when the brightness is set fairly low.

iMac, OS X Mountain Lion (10.8.2)
  • BDAqua Level 10 Level 10

    I still see it mentioned from time o ime, so I guess not.


    Do you still have AppleCare on it?

  • baltwo Level 9 Level 9

    Contact Apple Service, iMac Service or Apple's Express Lane. Do note that if you have AppleCare's protection plan and you're within 50 miles (80 KM) of an Apple repair station, you're eligible for onsite repair since yours is a desktop machine.  Might also apply to new machines the first 90 days. BTW, the AppleCare Protection Plan's the best insurance policy available for desktop machines. Get it if you don't have it before contacting Apple.

  • MrComputer Level 1 Level 1

    I have this too after the 10.8.2 Upgrade!

  • Justan Oldfart Level 2 Level 2

    I had that same problem on a mid 2011 refurb that I bought from the Apple store. I had to turn the brightness up full to torch mode to stop the flashing and flickering. As that was unsatisfactory I returned it to the store. Seems like backlight problems are not that uncommon with the late model iMacs. Baltwo has suggested the proper course of action for you to take.

  • Slapera Level 1 Level 1

    Same problem after 10.8.2 menu and safari page scrolling flickering on iMac mid 2011

  • Cthulhu Level 1 Level 1

    Ditto on my MBP running ML and connected to an external LED Cinema display.


    Tried resetting SMC, PRAM, re-installing, disabling auto-graphics switching, your name it, it's likely I tried it.


    The only workaround is to turn the brightness all the way up. I suspect the issue is still there, but I don't notice it because the bright light is burning into my retinas.

  • Nomax2001 Level 1 Level 1

    Hey, i have the same issue. Is there already a solution?

  • Cthulhu Level 1 Level 1

    Nope. But I do find I don't see the flicker if I 1) put my Gunnars on, and 2) keep the brightness at six of those little squares or higher. Apple was no help. They didn't see the flicker, and I was looking right at it saying, "Are you kidding me? You can't "see the brightness changing?!?" For the record, this is not subtle. It's bad enough that I simply can't work with the brightness low.

  • 3gs LS Level 1 Level 1

    There is clearly a hardware problem with this model. The screen flickers at a fast rate and can be hard to notice after a long period of use although it does randomly flicker worst than usual in some cases. I notice it most when the screen is displaying white and grey backgrounds when the brightness is set low. It's not so bad when the brightness is turned up high. I will take it to an apple store soon and see what they say.

  • Cthulhu Level 1 Level 1

    3gs LS,


    I don't know if it is a hardware problem. My mid-2011 MBP does the same thing when connected to an external display as your iMac. It started the moment I upgraded to Mountain Lion.


    An identical MPB running Lion attached to this monitor does fine (no flickering). If I attach mine to another Cinema Display - flickering.


    That almost certainly means it's a software issue (or in my case I suppose the MPD external video hardware could be faulted), because the monitor is completely fine. The timing of my update, however, makes the software highly suspect.


    And one more thing - I am unable to reproduce this unless Safari is running (it does not have to be the active app). Perhaps it is something in the Automatic Graphics Switching, although I have it disabled, as well as the option to "Automatically adjust screen brightness."


    Please let us know how your visit to the Apple Store goes. If they fix it, I'm taking mine back in with a printout of this discussion.

  • 3gs LS Level 1 Level 1

    My iMac was flickering before Mountain Lion. Maybe it is a software problem though :/ All I know is that the problem is widly reported on 2011 iMacs and external Apple displays. I'll let you know how I get on trying to show this pulsing screen.

  • 3gs LS Level 1 Level 1

    I finally took my iMac back to the apple store yesterday and they advised that the problem could be related to the software. They installed a fresh copy of lion but when I got home and turned it on I could still see the flickering issue. I upgraded to mountain lion as before and the issue was still occuring. My machine is in warranty so I am going to take it back again as I'm not happy.

  • baltwo Level 9 Level 9

    Did you turn it on at the store? If not, you should always do that to ensure things work as expected.

  • 3gs LS Level 1 Level 1

    The iMac was turned on as I waited in the store whilst the install took place. I took it in due to a Wi-Fi problem which is also reported on the apple forums as well as the screen flickering issue. I am struggling to prove both issues as they are intermittent faults. It is also hard to demonstarte the screen flickering when the brightness is set low due to the type of lights used in the store.

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