Home > Mac > My Intel ‘Aluminium’ iMac 24″ roasting with dark spots on screen

My Intel ‘Aluminium’ iMac 24″ roasting with dark spots on screen

My gorgeous iMac 24″ has started getting VERY HOT over the summer, with my room reaching just over 30C in the day time, this can lead to the thing reaching 80 degrees or more internally.

I’ve installed a fan controller to boost fan speed and this has helped reduce the temperature down to the low/mid 60’s

More worrying, the screen has started developing dark patches here and there. At first, there was just one or two, down the left hand side, towards the bottom of the screen about two-thirds of the way down, but now they have multiplied to about ten and a new patch has sprung up on the right hand side.

I hope it’s nothing to do with the heat.

Luckily, I have my three year Apple Care, otherwise I’d have been panicking, since the one year guarantee is almost up (I bought the thing in September, last year).

Anyway, here’s a couple of photos I took: I won’t insult your intelligence by circling the black patches with red or pointing at them with flashing arrows. Instead, I’ll leave it to your keep observation to see if you can make out what I’m talking about.


I fixed the focus about 1cm in front of the screen to try to minimise the moire effect.


Here’s a slightly darker one, with regular focus. The strange banding is moire, due to the camera and the screen pixels interfering.


What’s important in the above pictures are the two clusters of round, blackened circles appearing and the general blotchiness of the screen. Not to mention the fact that the left is brighter than the right and strange, colour shifts occure in patches here and there.

Makes me glad I splashed out on the Apple Care.

Come on Apple, you can do better than this!

Categories: Mac Tags: , , , ,
  1. Pilates
    August 12, 2008 at 10:51 pm

    Why is your screen white?

  2. nanchatte
    August 13, 2008 at 5:52 pm

    I just used the background changer and chose “solid colour – white” to make it easy to photo the black splotches which have appeared.
    Although, now they’re so visible I could just keep the screen with the Tiger blue desktop I usually use.

  3. E
    September 1, 2008 at 11:24 pm

    I’ve had a dark ring of pixels in the upper right of my screen for a couple months, I’m glad I’m not the only one. Now I’m definitely going to pick up Applecare (I also bought my iMac in September of last year).

  4. nanchatte
    September 2, 2008 at 10:59 am

    Yes. They replaced my unit without question. Actually, I got an entire new machine. They just whipped out the hard disk and put it in a new body. The current screen is PERFECT!

    Also, I feel this next sentence is important enough to merit capitals:

    And APPLECARE appears to be about the best there is! In my experience, their support staff are patient, friendly and listen carefully. For example, they didn’t make me go through all the rigmarole of hardware testing, etc. A photo posted to my blog (THIS ONE!) was enough.

  5. E
    September 15, 2008 at 10:12 am

    Jeez heh – I just had another 20″ iMac replaced because of random shut downs. Took six days for a repair. It would be a dream to just get a new (or refurb) machine without having to back up and securely erase all my data… that’s just the biggest pain in the neck. I wouldn’t expect that going to the 5th Ave Apple store in NYC. But I definitely agree, AppleCare IS worth it.

    It’s interesting you mention the Aluminum frame at the top left of your iMac is really hot, mine is also… which is probably what led to that dark ring I was talking about before; PLUS there are more dark spot coming up in the same area. That said – I’m going to pick up AppleCare tomorrow… & maybe a new iPod Touch 😉

  6. Alessandro Cintoli
    September 18, 2008 at 11:03 pm

    I haven’t reached the stage you describe in your post, but my iMac, purchased June 30, 2008, is being sent for repair to Apple’s NATIONAL repair center for Italy for overheating and excessive burn-in on the left-hand side. Of course, no-one explained to me what is causing the problem, but the person who contacted me didn’t even care sending a technician to my home (I have AppleCare, too, it was a wise/obvious purchase decision, after my 2006 Mac’s graphics card fried) which seems to me that she knew there is a flaw in this batch of iMacs. Of course, my 24″, custom-made iMac was made in China. Sabotage, anyone?

  7. dave
    November 25, 2008 at 9:25 pm

    well my initial experience with applecare operatives over the phone was less than perfect. I had a malfunctioning DVD burner which I had tested thoroughly and knew it was fritzed. It caused numerous system freezes until I stopped using it, appeared to burn discs, (but burnt discs contained no data ) and also made a horrible grinding sound when blank media was inserted . I made the mistake of telling the apple guy this and he then tried to say that I had dropped a paperclip into the burner ( this being a G5 tower on top of a desk- I would have had to throw a clip sideways into the slot to achieve this ) . After ten mins of explaining all symptoms, genius then asked me to burn a disc for him. I told him I would not , I was an experienced user, Id tested all sorts of media in drive on various programs and I wasn’t going to waste another disc . He then got a supervisor online and after another ten minutes going through all the processes I had already explained to the other guy then told me I was
    being awkward and that I should bring in the computer to my nearest store as it ” would be easier for me ” this was when I lost it and gave vent to my frustration at not being believed by these guys. The whole point of me going on the phone was to get someone to come see the machine as I knew full well my local store would have taken about three weeks to get a new burner installed and it would have entailed a 160 k round trip taking and fetching. Anyway they said they would have a technician get in touch with me . I waited THREE MONTHS , then braved going on the phone again – completely different experience, friendly Irish guy who swiftly found that the goons had marked my case as ‘ waiting for me to get in touch re technician visit ” a three minute phone call, a reference to a local tech who came next day replaced burner- which was stuffed as i thought- case solved. However, I think with applecare one can get a very variable response depending on who is dealing with your case…..

  8. December 25, 2008 at 9:23 am

    I have the same problem. Got an appointment for the 27th to see what the Apple Store has to say about it.

  9. December 28, 2008 at 5:04 pm

    Well, Apple says it’s covered, but I have to wait a week to get my iMac back. Oh well, time to pull the old PPC mini out of the closet.

  10. Sammyjoe
    February 1, 2009 at 6:01 am

    I just noticed yesterday that my Apple Mac had quite a few dark spots on the screen, i shut it down and noticed you can see them with the computer off, this is a huge problem i am finding out with these macs. I did purchase the appplecare and have an appointment tomorrow. I will not accept anything but a brand new machine. I have read about numerous motherboard replacements and screen replacements and it comes back. Be careful when you buy something so expensive and make sure you purchase your extended warrranty.

  11. Peter
    February 1, 2009 at 11:59 pm

    I’m experiencing the same problem. Were you able to get your problem resolved? If so, what happened?

  12. February 23, 2009 at 10:06 pm

    I am facing the same problem with my iMac 20 inch. I am in graphic work and these patches are disturbing me in my work. Whats the reason of these patches

  13. nanchatte
    February 26, 2009 at 12:11 am

    I’ve no insider information or light to shed on the problem, but I suspect its something to do with the intense heat the imacs tend to build up when under prolonged heavy load (such as encoding).

    My iMac’s PSU regularly got up to 80C in the summer (Room Temp Ambient 35+ w/o aircon) when I was encoding HDV tapes into h264.

    I think the polymer Fresnel lens that directs the backlight forward or some other plastic element may have become discoloured by the intense heat.

    To reduce the heat, I have installed SMC Fan Control which keeps my PSU below 60C even during Tokyo’s horrible summers, with a bit of judicious fanning.

    I’m into the second year of my Applecare now, so I might experiment this summer and see if the patches come back. if they do I’ll have found the cause with a year left to spare on my Applecare.

    I’ll keep you posted of any developments.

  14. April 26, 2009 at 4:04 pm

    So it took about four months for the problem to return. Apple has the iMac again, and this time they are also replacing the power supply. They claim the new power supplies don’t run as hot.

    Time will tell, but somehow, I’m skeptical that this will fix it.

    Incidentally, I asked if the current-generation iMacs contain any additional shielding or fix for this problem, and the “genius” said no. So it sounds like not even a replacement machine is a guarantee of a fix. 😦

  15. Peter
    April 27, 2009 at 3:55 am

    Had the same problem, but it seems like replacing the LCD solved the problem. It’s been about a month and the problem has yet to return. Thank goodness it was still under warranty.

  16. nanchatte
    April 27, 2009 at 3:38 pm

    I’ve never been one to purchase extended warranties on anything before. I’ve always been of the opinion that if it lasts a month, it’ll alst ten years. But I’m really glad I got my Applecare with this beast – heaven knows what it’d cost to replace the screen otherwise.

    I’ve had about six new keyboards and a new screen, so I’d say I’ve about got my money’s worth already.

    Interesting that the bloke said the new power supplies run cooler, that’s an obvious admission that the current ones are a trifle too hot… Mine peaks at 80C in the summer without SMC fan control running at 1750RPM, 60C with it.

    I’m sure it was the overheating last summer that did it.

    I’ll see what happens this summer, where the ambient room temperature can hit 34 in the day time.

    To be honest, though, I’m really scared to test the thing, since I bought it in Oct 2007 I’m already half way through my Applecare. I’d hate to stress it and have it break down just outside warranty.

    But you cat bet your bottom dollar that it’ll pack in a month after three years is up, no matter how you treat it.

    Stian, let me know if the new supply does indeed run cooler.

  17. September 7, 2009 at 10:43 pm

    It really pisses me off when people get fucked up iMacs which fail before the 1 year warranty is up and then say they’re going to pay Apple for AppleCare. That’s totally playing into Apple’s hand. What you should do is call Apple immediately, before your 1-year warranty is up, and demand that they fix your machine and give you AppleCare for free! I mean, think about it: you paid top dollar for an iMac which is basically defective out of the box, and because of this you’re going to give Apple even more money? This is exactly why the quality of Apple’s products is going into the toilet. It’s because by making money off of AppleCare they’re encouraged to skimp.

    • nanchatte
      September 8, 2009 at 9:49 am

      Yes. Defective out of the box and unsuitable for purpose in many cases. Well stated. I really feel for people who end up with a mac that packs in in the 13th month.
      Still, if enough people make a fuss outside of AppleSphere they might start to take notice in order to protect their reputations.

      Hit them where it hurts: their image.

  18. October 20, 2009 at 11:55 pm

    The new PSU ran as hot as the old one; I was hitting around 80C just at idle (although “idle” on my computer still means two active virtual machines in VMware Fusion, so that’s a bit of a load in and of itself.)
    Also not surprisingly, the blotches returned after about three months.
    I ended up taking the machine to Apple a third time. This time, they replaced it immediately. They offered to transfer my data for me; I declined. (I’m paranoid about other people poking around on my hard drive, so I always do a 7-cycle secure erase and load a stock Mac OS X image on my drive prior to my appointment.) I was given a brand new iMac, although they insisted on keeping the box so they’d have something to ship my broken one back in.

    I am glad I purchased AppleCare so that I didn’t get told I was out of warranty. However, Mark Alan Thomas has a point. This is not a normal warranty issue; this is a defect in these computers and warrants a recall/extended warranty program. Unfortunately, Apple historically doesn’t own up to their mistakes until forced to do so by bad publicity. (Notice how they tried to silence that UK family whose iPod exploded? “We’ll give you a new one if you keep quiet.”)

    My replacement is the “Spring 2009” iMac (iMac 9,1); my original was a “Mid-2007” iMac (iMac 7,1). I asked the “Genius” if the newer model had a heat shield or some sort of redesign to better protect the LCD.

    Somewhat to my dismay, he told me the internal design is pretty much exactly the same. I’ve had this new iMac for about 3 months and so far the symptoms have not returned, but I have to admit I’m worried they will eventually. My new hard drive runs a little cooler than the old one did, but other than that the temperatures are similar.

  19. Benjamin Kee
    April 12, 2010 at 6:31 pm

    Spoke to Apple today regarding a very similar situation with the screen. I have change the screen every 2 months since August 2009, because of screen burn in or some other issue with the screen.

    Just spoke to them today, they are saying it is an environmental issue where the machine is being used and as such they are not willing to replace the screen, given the history of my machine’s screen replacement.

    This is what they replied, “the dark patches may be environmental but its impossible that this customer is the only one to get panels with this defect consistently.”

    This is Apple saying this is not their problem anymore and they are not going to honour the warranty.

  20. Alex Solla
    July 5, 2010 at 7:26 pm

    That’s “burn in”, but it doesn’t have anything to do with temperature. I can tell the little dark spots on the bottom left is where you constantly keep an iChat window.


    • nanchatte
      September 10, 2010 at 12:41 pm

      NIce theory… never used ichat, though… it’s absolutely not LCD burn in, which does not affect passive displays such as LCDs… You are perhaps getting your wires crossed with active displays, such as CRTs or Plasma displays where the phosphors burn out with extended use… At it turns out, there are hot IC chips in proximity to the reverse of the panel which are causing the plastic backlight focussing lens to discolour.

  21. October 8, 2010 at 10:24 pm

    I ve experienced the same screen problems like everyone else here. However I would like to report that the official service provider, named System Graph EPE, for Apple in Athens, Greece where I live totally refuse to replace faulty units. In my case, I brought my 27″ intel iMac in their service, they replaced the lcd panel inside with another faulty panel! I complained in writting and I was literally kicked out from their store when I visited a second time!!! The man in charged bullied me by saying “take it and go somewhere else”.
    Mind, that consumer law in Greece, dictates in specific that the customer has a clear choice to request a refund, replcament or repair while under warranty for any faulty product after initial repair. This is what Apple after-sales services look like in Greece at the moment. I am now in the middle of a legal dispute and the company that imports apple products, namely iSquare, is doing their best to avoid a refund or replacement. Of course, no word about ethical reimbursement of any kind for the delays or the treatment I received at System Graph. Makes you feel they are doing you a favour they sell you Apple and talking to you! Apple consumers in Greece are simply.. insignificant for Apple.

    • nanchatte
      October 21, 2010 at 1:44 pm

      That’s really disappointing to hear. I’m in Japan and the quality of service is phenominal I’ve had a computer shipped Saturday morning and had the replacement shipped back Sunday evening! But bear in mind that it was six times the thing went back before I got my replacement. I hope you can get a positive result.

      By the way, were you getting burns on your 27″ inch? I have been getting burns on the previous 24″ models… I hope that this computer doesn’t suffer the same fate as the last one….

  22. Rohit Singh
    December 30, 2010 at 1:12 am

    I purchased a top-of-the-line Apple iMac 27” (2.66 GHz Intel Core i5, 4GB RAM) in June 2010 for my new software development startup. The stunning all-in-one display was a big factor in my choosing a Mac over a Windows PC, for which I had been primarily programming earlier. The Apple reseller I purchased this from strongly recommended that I also purchase the 3 year AppleCare Protection Plan (APP) so I could get peace of mind with this new system, as AppleCare would cover the complete system, including the display, for 3 years as opposed to just one year without it. Additionally, APP would provide at home repair and I needn’t lug the system around in case it needed service. I trusted Apple with my money, and purchased the APP to cover my investment in the iMac, not knowing that all this was hogwash and I would still need to run from pillar-to-post when the time to seek repairs actually came.

    Within just six months, I started noticing some dark spots / patches on the screen. At first I thought that these were on top of the glass but when I looked closely and made sure the glass screen was clean, I was shocked to find that the patches were within the display itself. I was still not very worried and trusted that Apple would take care of the problem as I had the AppleCare Protection for 3 years and it was still well within the first year that I had this problem.

    I contacted Apple support and logged a support case with them on 25th November 2010. Apple referred this case to their authorized support center (UC Infosystems) and the technician who saw the system acknowledged the problem and mentioned that the screen needed a replacement, and Apple would cover it as it was under warranty. The service center ordered a screen and came over to replace it. The first screen they got was clearly defective as it had prominent dark bands running from left to right through the entire width of the monitor. Needless to say, the technician took the screen back right away and asked me to wait for another replacement while they got it from Apple. The replacement screen came and it was changed on 3rd December 2010. Upon replacement, I noticed that while the screen did not have any patches, it did have a dark band in the bottom edge as well as yellow tinge across the right and bottom edges as well as in the center. When I mentioned it to the service technician, he brushed it aside saying that it wasn’t a problem and it was probably my imagination. He suggested that I work with the system for a few days and contact them in case I still have a problem. I reluctantly agreed as the main issue of the patches had been resolved, and I didn’t want to create a fuss about this somewhat subjective issue.

    To my shock, within 2-3 weeks of having the replacement screen, I started noticing dark spots and lines developing once again. This time, the problem was even more severe than what I had with my original screen. Photos of the display showing this problem are here:

    The photos have been taken in a dark room to avoid any reflections, and to give a true picture of the problem. The display is clean on the outside and the dark patches and lines are very visible in the top right corner extending to almost the middle of the display. There is a prominent dark band near the bottom edge going across the screen. Additionally, you will notice that there is yellow banding on the right and bottom edges of the screen and a yellowish patch in the middle.

    I contacted Apple support once again (on 28th December 2010), and was assigned another support case (Case Ref # 195112734). The Apple service and support center technician came by and took photos of the screen with his mobile phone to send to Apple before they could order a replacement. He also acknowledged that the display was indeed defective and needed a replacement. Additionally, he mentioned that while this problem was widespread, Apple recently started denying some screen replacements without much explanation. I still had my trust in Apple as they had built a reputation for good products and service.

    The same evening, I was shocked to receive an email from the service center that ‘Apple had declined to cover this issue under warranty’ without any other explanation or reason and that I should contact AppleCare if I had an issue with that. I was completely shocked that they could do this as the problem was clearly in their display, the system was less than seven months old, and I had also purchased AppleCare Protection Plan for ‘peace of mind’ which clearly I didn’t get given this episode. I called AppleCare and narrated this to the support representative. His noted mentioned that the issue had been resolved (without any clarification on how it was resolved)! He then consulted with his supervisor who spoke with me and mentioned that technical people had seen the photos of the iMac display and determined that there is no defect/problem with it, and hence Apple could not cover the issue. I mentioned to him that the service technician had taken his photos in poor light with a mobile phone camera and I had better photos that clearly show the issue. The supervisor asked me to email him the photos and said that he would immediately take up the matter with the technical engineers. However, he mentioned, that there were no promises that Apple would cover the issue, despite the issue occurring on a screen Apple itself had put in just 3 weeks ago and my having purchased AppleCare Protection Plan. I emailed him the photos right away and requested either repairing or replacing the display. This happened yesterday and I am awaiting a call or email back in response.

    I should also mention that I take good care of my computers, don’t smoke (if smoke damage is what Apple is thinking of blaming this on), and that the system is kept in a nice, clean, low-traffic home-office environment, where I have 5 other computers/laptops/UMPCs which have no such issues. I have purchased several Apple systems (including a MacBook Pro laptop, two Mac Minis, iPhones – both 1st Generation and 3G as well as a couple of vintage Macs) and not needed to report issues to AppleCare in the past. Now, when I truly needed the AppleCare support, I am being denied it. I am a reasonable person with low demands, but the way Apple is treating me with this case is pathetic.

    I sincerely believe that I have a genuine support case and I am not getting the product and service that I paid top dollar for. The display I got was clearly defective as the pictures show for themselves (and the problem is with a new display that Apple just provided three weeks ago!) No amount of environmental factors in my home office can cause the issues I am having. Apple needs to own up to the problem and be the company with high morals that Steve Jobs is presenting it as.

    I will keep you updated on how this case proceeds, but a few disappointing things I am learning of now are:

    • Apple iMac 27” screen isn’t really that gorgeous and cannot even last through it’s warranty period without developing dark spots, lines, bands and yellow tinges.

    • Apple is trying to refuse acknowledging that their iMac’s displays have a design or manufacturing defect that is causing these issues (dark spots/patches, lines and bands, yellow tinge). This is despite the fact that several people have reported these issues and posted pictures online showing the problem.

    • AppleCare Protection Plan is hogwash. Apple can refuse coverage under the plan, and the customer is at their mercy. This plan certainly didn’t give me the peace of mind that I thought I bought when I paid for it. This is even within the first year of purchase!

    • While Apple products are gorgeous to look at, they are not built to last. If your Apple computer develops a problem, you’re out of luck. Your honeymoon is over. Given the number of issues people are reporting with the iMac 27, especially with the display, this is more likely to happen than not.

    Given my experience, this iMac will be my last Apple purchase, and I wouldn’t recommend Apple products to anyone, nor develop software for the Mac, unless the issue is satisfactorily taken care of by Apple.

    • nanchatte
      February 10, 2011 at 6:29 pm

      How did this pan out? Did they replace the screen or otherwise fix the problem? as you know from my experience, I have nothing but good things to say about Apple and how they replaced my computer multiple times under Apple Care.

      I hope you were satisfied… If you, you could easily take this up with a Citizen’s Advice Bureau.

  23. April 3, 2011 at 4:34 am

    Well, it happened. The 2009 replacement I received for my 2007 iMac due to this issue is now showing the same symptoms.

    But this time, the AppleCare is expired, so there’s no way to get it replaced. I suppose I’ll wait until it gets too annoying and then buy a new computer. But it won’t be an iMac, especially given that the same problem still seems to haunt the new 27″ iMacs.

  24. June 3, 2011 at 4:20 am

    From the Philippines here. Same problem here guys!

  25. Dustin
    July 11, 2011 at 10:24 pm

    I´ve had the same problem. I thought the dark patches were burns in the display. After doing a little googleing around I found a video on You Tube showing how to remove the glass cover of the iMac. (It is super easy by the way, no screws to mess with.) I cleaned the back of the glass cover and the front of the LCD with a microfiber cloth and noticed some black build up. After replacing the cover the smudges were gone. No fussing with Apple or their retailers. I hope this helps some of you!

    • nanchatte
      July 12, 2011 at 12:03 am

      Thank you for the info, but in my case, each and every time (all 7? times) the dirt was between the backlight and the lcd panel itself. Apple replaced the screen each and every time and I even got a new 27″ iMac as compensation.

  26. August 6, 2011 at 3:56 pm

    Same problem here (Norway) with my 9 months old machine. I just wonder if when Apple is working/replacing stuff on the machine, the Machine comes back with a warranty extension?

    I mean, when my Canon camera got a problem, Canon fixed it and I got 6 months extra warantee, which I think it’s normal because they did work on it.

  27. August 6, 2011 at 3:57 pm

    Stian Oksavik :
    Well, it happened. The 2009 replacement I received for my 2007 iMac due to this issue is now showing the same symptoms.
    But this time, the AppleCare is expired, so there’s no way to get it replaced. I suppose I’ll wait until it gets too annoying and then buy a new computer. But it won’t be an iMac, especially given that the same problem still seems to haunt the new 27″ iMacs.

    Are you Norwegian ? How did you solve your problem? Eplehuset ?

    • November 6, 2011 at 6:58 am

      I am Norwegian, but I lived in the United States the first time this happened, so I got it replaced under AppleCare in Florida.

      The problem I have now occurred after AppleCare coverage expired, and I haven’t gotten it resolved. The computer is going to be four years old soon. I will eventually replace it with something else, but not with an iMac.

      • Skygge
        December 12, 2011 at 11:00 am

        Hei Stian

        My problem was quickly solved under warrantee at Apple Store Bergen. The problem is obviously a flaw in the product, so call them and try to negociate, even if warrantee is out. Maybe you get lucky. Just be a bit strict but polite (meaning: don’t be nice and Norwegian^^)

        Hilsen Thomas

  1. October 10, 2010 at 11:41 am
  2. November 15, 2010 at 4:25 pm
  3. November 15, 2010 at 5:00 pm

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