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IMac Screen goes Black

3818 Views 21 Replies Latest reply: Oct 12, 2013 6:09 PM by aerman RSS
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ffmed124 Calculating status...
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Feb 27, 2013 3:38 PM

Screen on IMac goes black (just like it went to sleep)  all of a sudden and the only way to get it back on is by hitting the power button.  When the computer sleeps, it will wake by tapping the space bar twice but when it goes black, this doesn't work.  After hitting the power button, the computer will go right back to the screen you were on prior to it going black, nothing is lost and it doesn't have to re-boot.  This started out happening once in a while like maybe once every couple of months, then maybe a couple of weeks, (didn't really pay attention to time frame) now it has happened twice today.  Does anyone have any idea's or suggestions on what may be causing this?  I have not noticed any particular application that was running when it occurs.  Any help would be apprecaited, thank you in advance.




21.5 Mid 2011

Mountain Lion

Version 10.8.2

2.5 Ghz Intel Core i5

4 GB 1333 MHz DDR3

Graphics AMD Radeon HD 6750M 512 MB

iMac (21.5-inch Mid 2011), OS X Mountain Lion (10.8.2)
  • BDAqua Level 10 Level 10 (114,830 points)
    Currently Being Moderated
    Feb 28, 2013 10:36 AM (in response to ffmed124)

    Hi Mike,


    Have you done a PRAM reset, CMD+Option+p+r...



    In fact, do 3 in a row, takes a bit of time.


    Intel-based Macs: Resetting the System Management Controller (SMC)...



    Have you blown the dust out lately?


    Get Temperature Monitor to see if it's heat related...


  • asterion2 Calculating status...
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    Mar 6, 2013 5:37 PM (in response to ffmed124)

    I could be wrong but if it is like mine, the screen goes really DARK BLUE not BLACK.

    Mine did this again for the first time in 8 months or so again yesterday. In the past I just

    turned it off, waited a minute or two and restarted without any evident damage being done.


    Here are my Specs :

    Intel Imac Core 2 Duo Model A1208

    2Ghz 2.5 GB memory and I just about a week ago installed 10.6.3 Snow Leopard O.S. that I purchased from the Apple store online for 19.99.


    Mine also develops intermittent Horizontal ( not Vertical ) pixelated lines on the LCD.


    I think they must be related in some way to HEAT. Normally these things happen when my SMC fan Control temp gauge gets up around 125 degrees farenheit.


    There used to be an apple support article number 58270, I believe that gave details as to how to remove the back cover and dust the inside to reduce the heat buildup. I am still looking for my printed copy and I cant find the support article on line anymore.


    I did what I could to blow the dust out from the inside and vacuumn it out, I installed SMC fan control and that for the most part eliminated the problem, however when I installed Snow Leopard they happened again. The lines appeared Immediately and then went away, since it has only been a week I have to keep watching. Then the Dark Blue screen thing happened again, and then for the first time ever a Kernel Panic. I restarted and all seems fine.


    I guess I am saying install SMC Fan Control and set that speed at 2,000 RPM, and see if that helps.

  • kerstin911 Calculating status...
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    Mar 11, 2013 3:21 AM (in response to ffmed124)

    hey ffmed124,


    have you solved the problem yet? because the text you wrote could be exactly mine as well and I have the same problem... no idea, when it happens. sometimes the screen went black more than twice a day and sometimes one week not..


    so, i contacted the apple support team today and the gave me the advise to look here at the community boards!





  • v.liessi Calculating status...
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    Mar 12, 2013 7:33 AM (in response to ffmed124)

    Hey there.

    First, sorry my english. I am from Brazil, and I have this same problem.

    To me, happen when I watch videos. From youtube, VLC, what ever.

    After some minutes whatching videos, my imac turn off. Just it. Turn off. I have to wait some seconds to turn on again.


    What can I do? I have the new iMac, and I buy it 2 months ago.

  • BDAqua Level 10 Level 10 (114,830 points)
    Currently Being Moderated
    Mar 12, 2013 11:44 AM (in response to v.liessi)

    Wow, that new... can you have Apple take a look at it?

  • teos Calculating status...
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    Apr 7, 2013 4:44 PM (in response to ffmed124)

    I have the same problem and have had it for about six months. Running 10.8.3. have had the Imac back to apple and they can't find a fault. Obviousley there is one. Apple needs to look at this seriously.


  • teos Level 1 Level 1 (5 points)
    Currently Being Moderated
    Apr 15, 2013 7:29 PM (in response to ffmed124)

    I found a fix for waking up the screen without restarting.  Create a hot corner to send the screen to sleep. When the scteen goes dark blue/black, click on the hot corner and press the space bar. The screen wakes up.

    No idea as to why it goes black in the first place yet.

  • fiona.mac Level 1 Level 1 (10 points)
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    Jun 25, 2013 4:37 AM (in response to ffmed124)

    This happened to me. 27" iMac, built mid 2011. Apple replaced graphics card (no difference), logic board (no difference), screen (no difference), power supply (bingo). Apparently there is a separate cable in the power supply that powers the screen. Replacing the power supply fixed my black screen problem... then I got a white screen problem and Apple replaced the iMac, but hey that's another story... so try your power supply.

  • glbirch Calculating status...
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    Jun 30, 2013 7:58 AM (in response to ffmed124)

    I have an 27" iMac that does the same thing.  The screen goes black almost immediately after turning it on.


    When it first started happening it was intermittent and you could not predict when it happened.  I power another monitor off it and it works fine even though the iMac screen goes black.  I also took it into the Mac Store when it first started happening and they told me it works fine, and it only cost me $95.


    It seem if the "geniuses" can't find anything with their diagnostic software, they can't fix anything.


    I now have two monitors off the iMac and it sits on the floor like a regular desktop.  It still runs fine but the iMac screen itself, will not work.  As soon as the machine starts, the screen goes black.


    I have three of these and two of them have had problems with the screen.  One is under a year old and have not had any problems with it yet.  When I called support, they said they have never seen this problem but it is evident that it is common.

  • fiona.mac Level 1 Level 1 (10 points)
    Currently Being Moderated
    Jun 30, 2013 4:29 PM (in response to glbirch)

    Absolutely the best thing to do is video-record your computer doing it. I did that so that even as an intermittent fault, the technician could see that it was actually happening. Don't know how old your iMac is, but surely there is a warranty obligation for Apple to fix this problem for you.

    Good Luck.

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