Stepppy

Q: iMac 27" Screen goes black repeatedly, but then settles for a while?

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.

iMac (27-inch Mid 2011), Mac OS X (10.7.4), 12GB RAM 1TB, AMD Radeon HD 6970M

Posted on Jun 24, 2012 5:44 AM

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Q: iMac 27" Screen goes black repeatedly, but then settles for a while?

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  • by girlsonboard,

    girlsonboard girlsonboard Mar 3, 2014 7:58 AM in response to SkinnyStudios
    Level 1 (0 points)
    Mar 3, 2014 7:58 AM in response to SkinnyStudios

    Well, after weeks of no problem using the substitute keyboad, it happened again. While the geniuses (not) at Apple suggested sleep was the issue, that is contradicted by the fact only the screen goes black, the sound and computer are still on.

    I noticed when it happened the computer was at maximum warm, so now I'm using it for shorter periods and not letting it get that warm, though in the past it still happened when the computer was cool.

    I did turn the brightness down, that's annoying but we'll see.

    I also switched to a plain wallpaper at someone else's suggestion.

    The attempted fixes feel like superstitions, They seem to work so we keep doing it, then they fail and we try something else.

    I agree this *****, Apple has not done enough to track down the problem, it obviously is recurring in multiple machines.

  • by micfur,

    micfur micfur Mar 3, 2014 8:14 AM in response to girlsonboard
    Level 1 (0 points)
    Mar 3, 2014 8:14 AM in response to girlsonboard

    The only thing that has worked for me is when I turn the brightness down to the last 2. Its very annoying but at least the screen doesnt go black. If I increase the brightness to say 3, within minutes it goes black.

     

    Apple have ignored this problem because they know it will be an expensive fix. Disgraceful for a company that sells such an expensive machine and makes so much profit.

  • by Motorcycle Michael,

    Motorcycle Michael Motorcycle Michael Mar 3, 2014 9:57 AM in response to micfur
    Level 1 (123 points)
    Mac OS X
    Mar 3, 2014 9:57 AM in response to micfur

    Sorry to see this is still going on, a vexing problem to be sure. I posted a fix last November in this thread (pg. 8?) - problem hasn't happened since - and included a photo of the culprit, two tiny connectors on the back of the 27" LG display used in these iMacs.

     

    The workaround of using power button to sleep then wake machine (set in System prefs's Energy Saver under 10.6.8) was pretty dependable, tho I have no explanation as to why. And the fix we found isn't one that Apple is likely to endorse, nor is it an easy do-it-yourself solution. A replacement display would include new connectors and cables and is the only other solution.

  • by girlsonboard,

    girlsonboard girlsonboard Mar 3, 2014 11:46 AM in response to Motorcycle Michael
    Level 1 (0 points)
    Mar 3, 2014 11:46 AM in response to Motorcycle Michael

    OK, new symptom, same problem. I let the computer go to sleep on its own. When I went to wake it up the screen was on but so dark it was unuseable. I had to force sleep and wake it back up for the screen brightness to come up again.

     

    MotorMike, thanks for your post. When you say hard to fix, can it be fixed?

     

    And in my case after a day or two of brief blackouts, the next day the computer would not stay on long enough to do anything. Happened three times until I changed keyboards.

     

    Taking it in after the second failure, the problem did not recur the whole time it was in the shop and not for several weeks once home. Same thing with the first repair, new hard drive I had a recalled one, several weeks no problem, then the problem.

     

    New keyboard, several weeks no problem, then the problem came back a day or so ago. But I've not yet had the full issue so I'm still using the computer, trying to keep it from getting warm though I don't know if that matters.

  • by Motorcycle Michael,

    Motorcycle Michael Motorcycle Michael Mar 3, 2014 12:50 PM in response to girlsonboard
    Level 1 (123 points)
    Mac OS X
    Mar 3, 2014 12:50 PM in response to girlsonboard

    Hi Girlsonboard

    Yes, that's what makes this issue so insideous - almost any movement, temperature or other change seems to solve it temporarily. From your description, guessing screen happened to blackout while machine was asleep but the sleep/wake trick brought it back, yes?

     

    I tried to describe repair as best I could, and it did work - machine hasn't blacked out since, and fix was simply unplugging/replugging those two tiny connectors on back of display a few times and making sure they were fully seated when I put machine back together. Disassembling machine and getting to those connectors is what makes repair difficult (and risky), but those tiny connectors clearly caused the problem in my case. Whether they oxidize or become loose over time I don't know, but they are weak enough to cause intermittent (random) blackouts.

  • by pbook4g5,

    pbook4g5 pbook4g5 Mar 3, 2014 12:54 PM in response to Motorcycle Michael
    Level 1 (0 points)
    Mar 3, 2014 12:54 PM in response to Motorcycle Michael

    ^Yes, I still fully believe the problem lies within the ribbon cable between the display and the LED driver board. As I stated in my repair notes a few pages back (and now a few months ago), the only thing I could do to fix the issue was to install a new display, which had a new display cable attached to it.

     

    I could find the main cable from the display to the logic board to replace, and that didn't fix it, but I couldn't find the cable from the backlight board to the display itself (outside of a new display) so I'm convinced its the connection with that cable.

     

    I don't think its temperature related, I think its just a bad connection somewhere on one of those ends.

     

    PS My replacement display (which is actually just a display pulled out of another "recycled" system, is still fully functional after almost 9 months of use.

  • by Shteuf,

    Shteuf Shteuf Mar 4, 2014 1:39 PM in response to Stepppy
    Level 1 (0 points)
    Mar 4, 2014 1:39 PM in response to Stepppy

    iMac 27", bought 1800€ in september 2011. It's been flashing for a few days, first time while working on after effects. Assuming it was a CPU or GPU issue, I then wondered about an overheat problem, and quickly understood it was screen-related. The system seems to run fine in background. It started Friday evening, we are now Tuesday evening and it doesn't flash anymore. It's gone ALL black, ALL the time. Of course I didn't buy the Apple care protection plan, I had macs since… well, forever. Never had any problem with them in a decade.

     

    Now Apple is a Chinese company that keeps selling their crappy products a tremendous amount of money. My girlfriend's MacBook Air also just came back from repair for what seemed to be a motherboard issue. This is scandalous guys, I'm offended. I love Apple for so many reasons, as a graphic designer I can only say that Macs are great computers, but as a customer I must say they tend to become useless pieces of beautiful aluminum & glass. I'm so disappointed, Apple, because I know you do everything for your hardware to give up on us at critical moments. While you show off your repeat golds and green awards of yours, you truly have no respect for environment.

     

    Cheers guys, go on and replace every piece of your macs because self-proclaimed geniuses told you so, I'm gonna stare at my black screen, hopeless.

  • by K Shaffer,

    K Shaffer K Shaffer Mar 4, 2014 2:21 PM in response to Shteuf
    Level 6 (14,367 points)
    Desktops
    Mar 4, 2014 2:21 PM in response to Shteuf

    And then, there are those who took apart their 27" & 21.5" to re-melt

    the solder joints on the graphic processor card on a cookie sheet...

     

    So, I wonder if that really works, or if those following their lead should

    put in another cookie sheet with actual cookies on board; so as to

    maximize results just in case the first mission fails, nobody starves?

     

    Good luck & happy computing!

     

    {PS: what happens in external display when the original goes black?}

  • by Mr.Fraser604,

    Mr.Fraser604 Mr.Fraser604 Mar 5, 2014 11:44 PM in response to Stepppy
    Level 1 (0 points)
    Mar 5, 2014 11:44 PM in response to Stepppy

    I recently had this happen to my iMac 24". Screen went black on start up after logo, but I could still see my mouse pointer. I tried to repeatedly restart my computer but nothing was fixing this error.

     

    Tried to reboot PRAM with Command, Option, P & R buttons at start up but this did nothing.

    Launched disk utilities by holding command & R keys at start up, ran disk diagnostics and got a good message.

    So I reloaded my computer from my last time machine back up (which took about 24 hours for some reason) and now it works fine.

     

    I am fortunate enough to have a certified Apple Tech as a friend, he has come across a lot of these issues, mostly relating to bad hard drives, but at times caused by updates.

     

    Wanted to share as I was getting very frustrated and this worked for me.

  • by francisbartley,

    francisbartley francisbartley Mar 11, 2014 9:24 PM in response to Stepppy
    Level 1 (0 points)
    Mar 11, 2014 9:24 PM in response to Stepppy

    I am having the same problem just starting but very annoying. I will be working and the screen will flicker a few time and then boom it is black. All i can do is button restart. It seems like the only answer ourside of shelling out another 1000 dollars to fix an already overpriced machene is to but another monitor, (non-mac) and set it in front of this non-working machine. I regret this purchase that is for sure.

  • by McBaub,

    McBaub McBaub Mar 19, 2014 7:41 AM in response to Stepppy
    Level 1 (0 points)
    Mar 19, 2014 7:41 AM in response to Stepppy

    Like the others my 27" iMac started having the same problem. Overheating was NOT the problem. If I set the screen brightness as low as it will go, it seems to work. Also, have read where the LCD/backlight kit needs to be replaced. At this point my main gripe is: why doesn't Apple address this (and other) problems directly? Why should any of us have to find the solution via a message board?

  • by micfur,

    micfur micfur Mar 19, 2014 7:45 AM in response to McBaub
    Level 1 (0 points)
    Mar 19, 2014 7:45 AM in response to McBaub

    Like McBaub, if I set the brightness at its lowest or second lowest it works fine. As soon as I increase the brightness beyond that the screen goes blank. Apple are letting themselves down by ignoring this widespread problem.

  • by Winchy,

    Winchy Winchy Mar 19, 2014 8:12 AM in response to McBaub
    Level 1 (0 points)
    Mar 19, 2014 8:12 AM in response to McBaub

    "why doesn't Apple address this (and other) problems directly? Why should any of us have to find the solution via a message board?"

     

    I'll take a stab at this. Let's see... Eventhough Apple is sitting on over 130 Billion in liquid assests, fixing chronic product problems that have been well documented by thousands of users and make things right for them IS NOT on their priority list?

  • by micfur,

    micfur micfur Mar 19, 2014 8:15 AM in response to Winchy
    Level 1 (0 points)
    Mar 19, 2014 8:15 AM in response to Winchy

    The number of views on this thread is over 50,000 and still Apple dont give an S H 1 T. Dont even bother engage online here to what is very obviously a serious product defect.

  • by Adamglittle,

    Adamglittle Adamglittle Mar 20, 2014 2:18 AM in response to SkinnyStudios
    Level 1 (0 points)
    Mar 20, 2014 2:18 AM in response to SkinnyStudios

    Thank you SkinnyStudios, it actually seems like there's no real fix. Appreciate your response :-)

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