Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

iMac 27" Black Screen?

For 6 long and painful weeks, my 27" iMac (10.7.5) has intermittently turned itself to sleep mode (black screen). It's driving me up the wall and sent my productivity through the floor. You'll be in the middle of something and whammo, black screen. I have to push the power button to get the screen to work again. It doesn't respond to keyboard or mouse.


The screen turns black when you're on the Internet, playing quicktime files, using Microsoft office, so it happens across different applications... it happens on my account, my daughter's account, the guest account. It is indiscriminate, it just does it whenever it feels like it, but not all the time. If it shuts down video, the audio still plays, there is just a black screen with no picture to watch.


The computer is 8 months old and I have Apple Protection as well, so that's not the problem, but I see other people have experienced a similar issue and I'm up for suggestions as to what you think might be causing the problem.


So far, these are the fixes that have been done and NOT fixed the problem:


  • OSX has been reinstalled twice
  • The logic Board has been replaced
  • RAM has been replaced
  • The graphics card has been replaced


The tech is coming back out Monday to replace the power supply and the screen. If this doesn't work I'm told I'll be reissued with a new machine.


So any other suggestions out there? Is it possessed by a ghost? Cursed? Just should be declared a lemon?

iMac, Mac OS X (10.7.5), Bought July 2012, Built mid 2011

Posted on May 2, 2013 9:56 PM

Reply
148 replies

Mar 16, 2014 6:57 PM in response to girlsonboard

Mine turned out to be a software issue. Machine would boot up, could hear the hard disk. Screen stayed completely black. Went to Radio Shack to pick up an adapter, hooked up antother monitor, it worked - so - whew! - it isn't the graphics card.


Main screen had been down for two days. After hybernating - it came back to life. I had the display back. Soooo... it was a software issue. Lion has been sort of dicey with hybernation from day one... I thought about attemting to find and replace faulty Kext files - but who's got time to dig around and find out where the issues are. Shouldn't Apple be doing this?


I upgraded to Maverics, and bingo! No more dicey hybernation. No more black screen. Issue solved.

May 3, 2017 12:48 PM in response to fiona.mac

I diagnosed this as a short in my keyboard - thanks to someone mentioning the keyboard as a possibility. My keyboard was sending out the key combination to toggle displays on a whim (alt+cmd+eject.) Whenever this would happen the main display would toggle off. Later on, on a whim once more, the keyboard would once again send alt+cmd+eject, the short would temporarily resolve and the main display would remain on for a period of time - until the next time... Replacing the keyboard absolutely fixed the problem.

Nov 12, 2017 7:12 AM in response to fiona.mac

I had downloaded a Sierra update and then plugged the charger cord into my keyboard. When I pulled the cord from the keyboard, everything went dark. This was yesterday. I then shut the iMac down. This morning I tried to log on but the screen had darkened more and was almost pitch black. Looking for an answer on my IPad, I found several suggestions Here. What worked for me was clicking on Preferences, Displays, and screen settings. Somehow the button for brightness had been turned to off. Also, I removed the option for automatically setting the brightness and I set it at my discretion. Hope this works for others.

May 3, 2013 9:38 AM in response to fiona.mac

I'm having the same issue recently (older iMac 27, Mountain Lion), though the iMac does not really go to sleep. It's only the screen that turns itself off randomnly, the Mac is still awake. To get it back on, I use the key combination alt-cmd-eject to actually put the iMac to sleep. Hitting any key will wake it up with the screen turned on again. Annoying. Can't find an answer so far as to where the problem is coming from.

Dec 19, 2013 12:01 PM in response to fiona.mac

I'll add my twopenneth here, after days testing an imac 27, swapping out the PSU I still have the same issue. The screen goes dark on test (not a graphics issue) as it continues playing videos from you tube I can hear the sound but there is no rfesponse from keys or mouse. The computer will stay active for a long time (overnight) and can be seen in network but can not be directly accessed. The system is only two years old.


I am frankly at my wits end with this issue I cant get any screen image on an external using an adapter. using tech toolsv7 shows no issue with any aspect of the system. Do I change the graphics card or is it something else?


Why no comment from Apple on these issues? - very very poor service!

Feb 10, 2014 7:14 PM in response to GV19

I replied in another thread but it applies here as well. I think it could be the keyboard.


I had the problem recur 3 times exactly the same, screen goes dark, computer is still on as the audio works. Twice the genius bar failed to find the problem.


Then I realized they use their own keyboard when I take it in. The keyboard has a brightness control, so it's not completely illogical.


I have a new keyboead and so far the problem has not recurred.

iMac 27" Black Screen?

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.