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

My screen was behaving itself, but it's just started happening again. There was a major OS update a couple of days ago. I can't help wondering if there's a connection.

But then Creative Cloud updated Photoshop and Illustrator, and there have been a number of other app updates. There are always things going on that could trigger a problem ...who can possibly be expected to figure it out? There are so many people affected it would be nice if Apple came up with an explanation and fix. Pretty please, Apple?

Sue

Hi Sue,

Bummer ... sorry to hear that.

An obvious question ... have you tried going through "my" routine again?

Ron

Hi,

I am having the same problem, my 24" iMac screen goes black but the computer is still running...I had to unplug the iMac and plug in an much older iMac to get online to read the post on Apple to find out what to do...evidently this screen issue has been happening to many others and I haven't read a solid solution. Never experience this kind of issue when I had a G3 and G5...I tried the suggested remedies, push the brightness up 100% and slide the sleep to NEVER and I rezapped the PRAM a few times and still no luck. In fact when I rezapped the PRAM and then I log back in, it goes black even quicker. I have not upgraded to the lastest OS, mine is still OS 10.7 Lion...I hate upgrading. Plus upgrading to the latest OS is not making a difference with this screen problem. If it's not a hard drive issue, what can it be? I find when I power off the iMac and wait a while, an hour, it would run fine for a few minutes and then the blackness comes back. There has to be something wrong with some internal part in the computer itself...? This black screen problem started at the beginning of this week for me, today is Feb. 7, 2016. Any idea what I can do...HELP!!!

Jack

Hi Jack,

Sorry man ... I feel your pain. We pay top-dollar (by about a factor of two) for what is "commonly-believed" to be a state-a-the-art home computer ... and this is what we get?

Apple does not "follow" this Apple.com thread?

Maybe they have a cash-flow problem? (Sales projections are down a bit, and investors are bailing ... a real downer on the company's bottom line.) Rumour has it that shareholders will be hosting bake-sales soon. Yacht slips/moorings on the west coast are being re-negotiated.

All I can say is ... try my work-around once more. Shower first. Try the sweetgrass smudge. If that don't work, move on. Pay somebody to try to save your files onto a PC.

Move on.

Ron Drysdale in Alberta

Hi Ron, thanks for your reply...I doubt if Apple is having any cash flow problems...I will probably contact my Apple repair shop and give them a call tomorrow. I wonder if they've dealt with this before. I really don't want to buy a new computer...If I learn anything I will post it. Thanks again for your reply. JT

Good luck.

This is maddening ... but I suggest that (if you haven't already done so) you maybe wait 12 hours and sit down with a cuppa coffee and read the whole ******* thread.

All that money ... I was joking about the cash-flow issues ... and these folks cannot be bothered to address or respond-to this issue on their own PUBLIC help thread.

Wow.

Ron

Hi Ron,

Just an update on my 24" iMac black-out screen issue I had...it was the video cart after all. There's now a new video card and the black screen problem has been fixed! My 2008 iMac is like a used car...I hope nothing else goes wrong. It cost about $475 for parts and labor (in CT) and it took about a week. Not ready to fork out two grand for a new iMac...yet. Hope this will be helpful for others who are having issues with blacked out screens. Be well.

Jack

Hello friends! 6 months ago I've got the same problem with my iMac 27" late 2009. I've changed the PSU, Inverter board, mouse, keyboard, reseted PRAM, Cleaned inside and all fans, disconnected all cables and connected again, Speed up fans with TG PRO. And nothing, problem continues.

3 days ago I decided to change all the RAMs. BAMMMM!!! PROBLEM RESOLVED!!

I tried in every way to make the problem happen again. I put the display brightness in all levels for hours.

If you have another RAM please try it!!

Running with 2GB for 3 days to test, with no problem!!

Andre Maffessoni

Hello All,

I have been following with interest, especially stepppy's post way back with exactly the same symptoms as my 27 iMac. They say that sometimes it can be the simplest think. After much head scratching and infuriation I delivered it up to my local apple accredited  tech shop. They opened it, cleaned it thoroughly to remove all accumulated dust and pronounced that it was overheating due to fan resistance. They did not charge me and said it took only a few minutes. I am delighted to say, it worked. It runs better, no black screen. Other than the embarrassment of feeling a little foolish for overlooking the bleeding obvious, I am very happy for their correct assessment, and integrity not to charge. This may be the first plan of attack. Clean out the dust. Hope this helps someone. TD

6 days running perfectly with my iMac 27" without any black screen. Changing the RAMs resolved my problem and the system now runs cooler!

Just wanted to let everyone know that after over a year of this repeating problem, the past week was especially bad---with the screen going black almost every 5 minutes.  Decided to bring my MAC into the Apple store to get it checked out.  Good thing I did--the tests they did showed that my hard drive was failing.  Apparently there can be many causes of this problem--a bad hard drive only one of them.  I'm mad at myself for not bringing it in last August while still under warranty but it wasn't that bad.  So, just like a health condition, better to get it checked out sooner v. later.  Will cost me about $180 but a small price to pay to have this problem fixed.

Hi Boomer and All,

Thanks for the put it up to 100% suggestion.  My screen will only stay on it seems at 100% or at the lowest setting!  My hard drive crashed on my iMac 27" mid 2011 (2.7GHz Intel Core i5 with AMD Radeon HD 6770M 512MB graphics card - not eligible for the video card program it seems) and i took it in to have a new one installed, and figured I would have my backlight issue addressed as well.  For 6 months the right side of my screen would occasionally go dark, without rhyme or reason.  The shop said the backlight card needed to be changed, which they did, but then after bringing it home and running it for a day, it started going completely dark.  I took it back in, thinking it was a defective backlight board, and they changed the card for another one, but the problem continued.  I am going through this thread trying things ... I tried the mfacci solution(PRAM reset, then Setup Manager - Dec 19 2015), but that did not resolve the problem   Still fishing  for a solution ... but at least I know I can use it at 100%!  Way better than the lowest brightness setting Would be nice for to have the option of an in between setting though!

So I brought my computer into the Apple store. .got a new hard drive and when I was updating the drive from Time Machine the screen kept going black.  unable to wake it up using the keyboard; the only thing that worked was pressing the on/off button..

Finally got everything up and running; set on 80% to test whether it's going to black out on me again. 

Late 2009 27" iMac (Intel Duo Core); .........I love my iMac but straight out of the box, I had a firmware issue that caused the screen to flicker black. It took Apple several months to figure it out and send out a firmware update. Then, the hard-drive crashed back in 2012 or 2013-ish. Apple generously replaced it at no cost after a recall due to a factory defect in my particular model; however, my CD/DVD drive and iPhoto stopped working when they returned it to me. (Now I've realized I can't reinstall Snow Leopard without CD optical drive working properly....... so there's a problem).  Anyway, I was ironically looking to upgrade my RAM when the screen started going black. I have to put the computer into sleep mode and then wake it for the screen / light to return. All applications still run in the background, though. This just started within the past few days.

Like most everyone else on this board, I'm looking for a real fix.

For those who've had this issue and then replaced the RAM, has the blackout gone away?

I tried replacing my ram and it did not help the problem. I have to run at 100% backlight or the lowest. If I change it to anything else it blacks out. Late 2009 Imac 27in. I have also replaced the video card, backlight driver board, and recently upgraded to a SSD drive.