mid 2010 iMac 27" screen flickering / blackout - any suggestions?

Hi Vittorio,

I was also experiencing the same thing with my mid-2010 imac that I purchased October 2010. At first, it would only happen whenever I am running graphically intensive programs but then it started happening when I'm just browsing the web or emailing so I took it the Apple Store last week. It started to happen more frequently as well and the only way to get around it was to shut down the computer and let it sit for a good while before turning it back on again. The only difference with our situation was that mine was not really flickering. It just goes to black completely. I can hear everything and if I'm on video chat with someone, they can still see me.

Anyway, I brought it in the store and the guys at the Genius Bar told me that it could be one of two things: dying video card or faulty display. So they put in the order for those two parts. I am supposed to get it back today but they still have not fixed it. I called them and they said that they have replaced the video card but that did not resolve it so they are going to test out the new display. I'm kinda worried that it is neither both and that they have to keep it longer.

The new video card is about $250 and the display is closer to $700. Luckily, I bought the extended warranty so I do not have to pay a dime. I've googled many times to see if this was a common problem and I've seen multiple forum postings about similar situations to know that this affects a lot of computers but I haven't really seen any resolutions posted online.

I'll keep you updated with what happens next.

Got my compter back. Turns out it was the display. I asked them what was wrong with it but they could not pinpoint it out so they just replaced the whole thing. The guy said it could be anywhere from faulty soldering or heat. The display is around $550.

I do hope that it's FIXED and won't happen again in the future.

Machine details: 27" mid-2010, 2.8 Ghz Intel Core i5, OS X (version 10.8), ATI Radeon HD 5750 1024 MB

I have the same iMac model and I recently upgraded to Mountain Lion. My screen started to adjust its brightness from low to high, or vice-versa, intermittently. I didn't notice this brightness flickering when I had Snow Leopard or Lion. I've called Apple Support and asked for suggestions of what the fault could be, they told me to boot on safe mode (hold the shift key immediately after you've pressed power button). Once loggged in on safe mode, I check if the brightness flickering still occurs. Luckily, it wasn't happening on safe mode. I've also experienced some blackout moments, it only happened twice.

They've also told me to reset the SMC, which resolves any hardware setting conflicts and could fix the brightness flicker. Unfortunately, this didn't resolved the issue when I logged in to my machine. I've also ran a machine test using the Apple DVD that came with my iMac, no errors were found but the brightness flickering still occurs.

I've been searching of what the issue could be online but most users resolved to getting the hardware or the display replaced, similar to what happened with molybdenum42. Since I recently bought the upgrade (Mountain Lion), I'm entitled for 90 days of support but I'm not sure if this will cover any hardware replacement for an expired warranty. I guess I have to result to buying the Apple Care Plan in case there are any hardware replacement on my iMac.

By the way, have you resolved your issue yet?

@molybdenum42: Did you have the Apple Care (or extended warranty) before the issue occurred, or did you buy the extended warranty after you've found out that there are hardware replacement required for the issue to be fixed?

Hi

I now have the very same problem. My mid 2010 27" i7 iMac's screen has an identical problem and I have the same situation as you, no Applecare. So I took my iMac into the Bristol Apple store and to cut a long story short they gave me the finger. The cost of the repair, £440. I complained to Apple public relations in Ireland, no result. I am now at the point of having to take Apple to the small claims court. Please could you help me out. Have you any information/copies of paperwork or evidence from Apple that explains the problem and their solution at the Bluewater store.

Thanks

I have an iMac 27 that was purchased in February 2011 but it is a mid 2010 model. I took it in to Apple yesterday. I noticed recently that the screen would flicker and turn off at random times. When set to the dimmest settings, you can see the screen (when surfing on Safari) constantly flickers. The people at Apple said they ran it through several graphic tests and couldn't find any issues.

Not only would my screen go completely black, but it would not come out of sleep mode after pressing the keyboard. The "genius" asked me if I could reproduce the problem. After several attempts to illustrate the problem, the computer always acted on its best behavior for the good people at Apple.

I also noticed that the screen would flicker like a lightbulb that was ready to burn out whenever it would come out of sleep mode. This happened several times in the past week. But do you think I could get this to occur in the Apple store? Unfortunately not.

I'm not at all happy with the performance of my iMac. Luckily, I have Apple care which will keep my computer under warranty until February 2014. If these issues persist, I will be demanding a new computer. I have read too many stories in these forums of iMac 27 computers with similar problems.

Hi, I hope you find this information useful:

A few years ago, we purchased iMac 27" 11,3 (Mid-2010) (with i7 2.93Ghz, ATI 5750 1GB VidRam, etc.) for our offices and software development team. They were originally shipped with Snow Leopard and worked as expected and without any problems. However, a year later, we upgraded to Lion and all of machines immediately exhibited the same problem: the screen would go to sleep by itself and would require a hard reboot or sleep on/off. (Only the screen was asleep and the rest of the iMac continued to function; this was confirmed by screen sharing to the machine.)

Due to the severity and impact on our business, we immediately contacted Apple and their genius bar staff in New York/SoHo. They were unable to determine the root cause, so they replaced all of the logic boards, video cards, and screens, and got us back online asap. This resolved the problem, but we were curious to know why. After days of rigorous testing, we concluded that the issue is caused by a bug in MacOS. Specifically, faulty Kext files (Kernel Extension files extend the functionality of the MacOS Kernel) for the ATI drivers. So, why did the replacing the hardware work? We think that the Kext files that were released and distributed with Lion (and later MacOS versions) correctly supported the newer hardware revision of the replacement components, but not the older ones.

If you're experiencing this problem, short of replacing the components or waiting (for another 3+ years) for Apple to hopefully fix their OS software, you can lessen the effects and be able to recover faster by doing the following: (Please bear in mind that these are not permanent fixes.)

1. Turn on "Hot Corners" and assign one corner to "Put Display To Sleep". When your screen goes to sleep, move your mouse (which still works) to that assigned screen corner for a second, then move it again. This will wake your screen. You may have to do this a couple of times, but it's much faster than a hard reboot or a sleep on/off for your iMac.
2. Turn the brightness of your screen to a low setting (10%-15% of the total brightness).
3. Turn on screen sharing, so you have a last resort method of accessing the machine.

If you're not convinced that it's a MacOS software problem, then do what we did and see for yourself; install Windows 7, Windows 8, or Linux via Bootcamp or as the only OS on the iMac. Those operating systems and drivers worked flawlessly for us; the bug does not occur and the screen does not go to sleep, but if you dual boot and switch back to MacOS, the bug reappears because the iMac is loading faulty Apple MacOS software.

Good luck!

I've had my screen replaced for fogging four times now and have the same screen issues as listed above (mid 2010 iMac, screen turning off when in use, screen sharing worked at first to show the machine was still working away and to save files) Most recently brought it in to CompuB in Dundrum after getting a response to my letter to Apple (invoking Irish Consumer Law - 6 years after purchased covered and if repaired once and not fixed entitlement to a replacement) which said they do not deal with these issues by letter....? CompuB in Dundrum in Dublin kept the machine for 3 months and couldn't replicate the problem. The found a problem with the hard drive and said it may be that it is overheating so they changed it. They sent me a bill for almost €400 for the diagnostics, screen replacement and hard drive replacement (which I had expressly asked them no to do). Needless to say I didn't pay for this as I finally found a way to speak directly to Apple in Cork (without paying €50 for the call) who informed me that the correct procedure is to fill out a 'Consumer Law Claim' form, which CompuB purposely hid from me. I filled out this form and they totally ignored it, replaced the hard drive and I took my computer home without paying a penny.

My consumer rights were completely ignored by CompuB and Apple, even when I spelled them out to them. They lost the original box I left with them (which I'd been storing in my tiny apartment for years-as I know there will be numerous journeys back to the shop), didn't fix the problem and now my screen share doesn't work at all....so the screen turns off and I can no longer see it to save files and restart the machine......

<Edited by Host>

Got the exact same problems with my iMac which is a mid 2011 3.4ghz i7 16GB with 2GB AMD Radeon HD 6970M video. Got the dark left half of the screen, I hear a soft but distinct high pitch sound which does not come from the audio and which stops when the screen blacks out. The problems started like a year ago, and increased in frequency since it started. I now have to bring brightness down so far it's almost not doable to use the computer anymore.

On youtube there are a lot of videos showing the problem (https://www.youtube.com/results?search_query=imac+black+screen+fix), and also some video's of people who were successful in fixing it. Apparently it's a problem with the connector which loosens up over time, if I understood correctly. Possibly due to heat?

I live in Holland, so I am going to contact a Mac Repair service that I found online and ask them if they can fix this problem (possibly resolder the connector like I saw somebody do in the video, if they believe that could solve the problem cause that way I wouldn't need to pay for a new screen.

Had seen this problem at a customer fortunately I could change only the electronic part of the display with one taken away from another display where the screen was broken… Since then it works…

See also : [GUIDE] Fix iMac flickering and dark screen problems out of warranty