imac 27 black screen

I'm having the same issue with a 4-month old iMAC 27, except I haven't noticed the screen turning back on again. Hitting the power button then puts it to sleep, so clicking the mouse or a button the keyboard will bring it back. I have two displays and the external disply doesn't turn off - just the iMAC's.

How come Apple only gives 90 days phone service? This is complete crap for a new computer that stops working.

Just recorded the following from Kernel.log. This is what happens when the display turns off. Not sure what it means, but there it is.

Oct 16 15:51:32 Mac kernel[0]: 19579.140447: performCountryCodeOperation: Disconnecting from AP

Oct 16 15:51:32 Mac kernel[0]: 19579.140450: setDISASSOC from disconnectVap

Oct 16 15:51:32 Mac kernel[0]: AirPort: Link Down on en1. Reason 8 (Disassociated because station leaving).

Oct 16 15:51:32 Mac kernel[0]: 19579.152479: setDISASSOCIATE ****STA SYNC DISASSOC SUCCESS

Oct 16 15:51:32 Mac kernel[0]: 19579.502989: setDISASSOC from disconnectVap

Oct 16 15:51:33 Mac kernel[0]:

Ignore the Kernel log that I posted above. Those messages were only being logged because I turned it to sleep and woke it up again to get the screen back. They don't show the cause and I haven't found anything in another log either. The problem is persisting and increasing in frequency.

I have experienced the same problem with a 27" i5 iMac. Also seen was a 1-2" band of distorted video flash near bottom of screen along with a 1-2 second black out of imac screen accoring randomly. Computer was just turned on with no applications running. I also have a another monitor connected to imac that did not show any of these video problems.

So I was going to reset the SMC System Management System (article: HT3964) and discovered after puting the imac to sleep using the the apple menu / sleep and wakeing it, the video issue has not reaccured. Not sure if the issue will return the next time I restart the computer but there has been no blink/blackout/distorted video for the past 4 hours.

I've been experiencing the same issue with my iMac 27. runing OS X 10.6.8.

screen goes black randomly and doesn't get back on. only if I make it sleep than it comes back.

it doesn't look like a hardware problem. any one can help or should I take it to an apple store?

My iMac 21" inch Mid 2011 running on OS X 10.7.3 does the same thing:

the screen goes all black but the computer is running. I can i.e. still talk on Skype while the screen is black but I don't see a thing. When I turn it to sleep and wake it up again the screen comes back but goes black all over again after just a few seconds.

The problem keeps getting worse so I'm not able to work at all. 😢

I talked to the Apple support team on the phone, but they couldn't help me. So I am going to get it picked up. I will let you know how it turned out and if they could fix it (which I really hope!)

Are you still experiencing this problem? My 27" iMac started doing the same thing today. I'm also running 10.6.8

Quad-core i7. Monitor goes dark and can't get it to cone back on without pushing the power button and forcing it to go to sleep and then waking it up again. Happened 3 times today and very concerned.

I got the same problem you are describing which started back in January (I bought it in May 2011).

It got worse and worse and 2 weeks ago I decided to go to the Apple store. They changed the Graphics card, saying the hw tests were fine. Basically they had no idea of what was happening and decided to change the cheapest part somewhat thinking I would feel better :-)

It did it once again the day I got it back, then was fine for a day, and multiple times the day after, including a reboot instead of a wake from sleep.

Last night ultimately it died last night..I cannot power it on again.

Probably a PSU issue, now I have to go back..what a pain.

Have them replace the LCD Display. they replaced mine last week and it's working great!

Ok, thanks for the update, I will go back to the store.. I felt relieved when it died last night, that behavior was so annoying :-)

Yeah it's sort of a nightmare. I had to go back a couple of times too. But they ended up being really cool and getting it taken care of in 48hrs. It probably wasn't the graphics card. They started with replacing my backlight board. Which fixed one problem but then started another, (LCD Flickering). So I went back, called customer care and they got it fixed asap. Best of luck...

Same problems here. Last week I had to bring my 3 month old Imac 27inch back to the shop for new hard disk. Now I've been working on it for one day and I'm having a black screen. Seems broken?! I'm gonna have to bring it back to the shop again. :-((