iMac 27" Screen goes black repeatedly, but then settles?

Discussion in 'iMac' started by Steppy, Jun 24, 2012.

  1. Steppy macrumors member

    Joined:
    Nov 21, 2011
    Location:
    Southampton, UK
    #1
    Hi

    I have searched and found numerous posts which sound similar to mine, but none seem to be so bad. Its a long post, but I want to make I have given as much information as possible

    My Energy Saver settings are default 10 minutes for display & computer sleep, but I always find the screen will go black for a period of time before it goes to sleep and normally when I go back to it I press the keyboard or trackpad and the screen comes back to life. However, this time it didn't. I tried everything I could, but in the end I had to hold down the power button until it turned off. Once I restarted it was ok again.

    I didn't think much of it, but I researched and found lots of people had similar issues, but were mainly on MacBooks. I did find a post where people had set a hot corner to turn the display off, so if the problem happened again they went into the hot corner and then came out of it and the display would come back on. This stops the need for having to force the computer off. I set up a hot corner, just in case it happened to me again and I'm glad I did.

    In the last couple of weeks the display has been going off at random whilst I have been using it, nothing graphic intensive, just web browsing. Going into my hot corner and coming out of it bought the display back to life thankfully. It was yesterday that things got really bad, to the point that the display was staying on for about 3-4 seconds before going off. Again, going in & out of the hot corner worked, but then it didn't. Initially I thought it maybe some kind of software issue, but when I restarted the grey screen would only show for about 3 seconds and then go black, so I didn't even see the Apple logo. I could hear everything start and it would pause at the logon screen. Going in and out of the hot corner several times finally gave me enough time to login before it went off again.

    After logging in I got it back only for it to go off again. I tired everything I could to get the screen to come back to life but it didn't want to play. All the time everything was working on the iMac, it wasn't frozen and didn't crash, just no display. I did some research on my iPad and this seems to be a common problem in one form or another, but no one that I could see had it as bad as mine. Some people were saying it was software related, other that it was logic boards, but as I said earlier I think the majority of posts related to MacBooks and not iMacs.

    This was my first Apple purchase and I feel like a fish out of water as I have always had PC's before and if they went wrong I just fixed it myself, but I don't think this is going to be the case this time.

    Very late last night I managed to get the display on long enough to run iBoostUp and let it give everything a spring clean. It kept going off whilst it was doing its things, but I did manage to get the display back for long enough to shut it down fully and I left it unplugged over night.

    It started working fine this morning, but after more reading I have reset SMC and PRAM as that advice seems to be given a lot when people are having problems.

    I have been using it for roughly a couple of hours and it has just this second gone off for the first time. I did my hot corner trick to get it back, then about 3 sends it went again. Now it seems to be ok again. The only program running is Safari.

    I am running Lion 10.7.4 with all updates done and I am not running Boot camp for Windows 7 I thought about doing a clean install, but I am not convinced that is going to work and don't want to go through all the hassle of that only to find it still does it! Taking it to Apple worries me, because as its intermittent it may not do it whilst they have it and also I am worried about all my personal data I have on it. Would they wipe the hard drive and would they access my files? I have never had this worry before as any PC problems I just switched problem items myself. The machine will be a year old in a couple of months and I am already thinking the AppleCare Protection Plus is a very good deal and a must have at £139 for two extra years warranty.

    Any suggestions great fully received.

    Thank you.
     
  2. dotcomet macrumors member

    dotcomet

    Joined:
    Dec 23, 2011
    #2
    I am having the same issue. I took it to the Genius Bar and after a diagnostic they have come the conclusion it may be a software issue. They are doing a reimage of the drive, which will hopefully correct the issue. I on the other hand believe it is a video card issue.

    BTW does your your screen ever flicker? Mine is doing that too.
     
  3. Steppy thread starter macrumors member

    Joined:
    Nov 21, 2011
    Location:
    Southampton, UK
    #3
    Wierd, I went in a saw a Genius and they reckon its not software :confused:

    I used to have some flickering about 4-5 months ago, but that seemed to go away after some updates.

    Where its so intermittent I dont really want to take it in only for them to not find any fault.

    I have bought another external drive and I am going to use Carbon Copy Cloner to make a bootable image just in case anything happens.

    Someone on another forum heard about someone flashing the graphics card with new firmware, but it has to be done via Windows, but im not sure how easy that is......
     
  4. dotcomet macrumors member

    dotcomet

    Joined:
    Dec 23, 2011
    #4
    Here's an update. It seems the there is an issue with the backlighting and some other hardware issues. As soon as i get the report I will post it.
     
  5. Steppy thread starter macrumors member

    Joined:
    Nov 21, 2011
    Location:
    Southampton, UK
    #5
    Thank you :)
     
  6. dotcomet macrumors member

    dotcomet

    Joined:
    Dec 23, 2011
    #6
    Was out of town, but got the call to pick up my iMac. they ended up replacing the LED Screen. Apparently there was an issue regarding the panel.

    Fixed and no issues so far.
     
  7. Steppy thread starter macrumors member

    Joined:
    Nov 21, 2011
    Location:
    Southampton, UK
    #7
    That's great news, thanks for the update.

    Tonight mine has been behaving itself so I have decided to wait until it forms some kind of pattern. :)
     
  8. Steppy thread starter macrumors member

    Joined:
    Nov 21, 2011
    Location:
    Southampton, UK
    #8
    Latest update.


    Finally my screen problem got worse to the point that only the right side was illuminated fully and the display started whistling.


    As I didn't want to be without my iMac for a moment longer than needed I booked a genius appointment at my local Apple store for Saturday morning to discuss my problem. Rather lug it in I took a photograph which I took of it starting up with the Apple logo as that showed brilliantly how the screen was only half illuminating.


    The guy at the Genius Bar knew immediately what my problem was from the photograph and my description of the other issues. He said it is a known problem on the 27" iMacs and they always keep in stock a new improved LCD & Backlight kit. He didn't need to see my iMac to do any testing and just said to bring it in and they would do the repair. I took it in the next day (Sunday) and got it back yesterday (Bank Holiday Monday).


    Pleased to report that I now have a fully functioning iMac. I can't believe how much better the display is after putting up with a problem one for so long. :)


    Incidentally, I had just 6 days left of my 1 year warranty which is a good job as otherwise it would have cost £440. I did buy the Applecare extended warranty about a month ago, so that is definitely money well spent


    Hope this helps for anyone else with this issue.
     

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