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Just wanted to add that my iMac 27" (late 2009) has recently started to exhibit the black blotches syndrome. Worth adding that it comes from a centrally heated, smoke free, candle free house with no real huge variations between hot and cold and no humidity issues. Also, when I do anything that may cause the GPU or CPU to heat up a little I use SMC Fan Control so the internal temperatures never get ridiculously hot.

...the problem is related to condensation on the panel which develops when you power down the system. Basically ...the computer needs to keep warm i.e. stay on all the time. Set the energy preferences to never let the system sleep and put the screen saver on. You can set the display to sleep but not the system. FYI, I have a dual monitor imac setup and my other monitor is the dell U2711 which uses the same panel as the 27 imac. I've NEVER had a problem with it - it's an amazing monitor.

I'm on my second black-spot screen, getting my 3rd panel this week.

My imac 27" is running pretty much 24/7 and the black spots began to appear a few weeks ago.
Same thing: in our office we've got Apple Cinema LED display, which due to the tasks has to run 24/7 turned on, Mac Pro has SmcFanControl installed for this display. And display had still developed these black spots! So as several other iMacs. But not all of them, some iMacs run about a year, they get heated pretty well, but are still alive.

Just wondering if everybody here who's had this problem happened to be using Boot Camp as well, or some other software that might cause extreme heat.
,
May I ask, do you often run Windows using Boot Camp?
-
...the problem is not due to gaming or Boot Camp
That's true. Our office has maaany computers and monitors, and we only had such problems with Apple monitors and iMacs. The Apple Cinema LED display had the same black spots problem as iMacs do. And that computer had never been used with BootCamp.

PEOPLE STOP PLAYING GAMES ON MACS AND STOP RENDERING ON MAC
they are NOT designed for it.
Maybe everyone that is buying 3000$ computer should never take it out of it's shipping box at all, so that it will not get destroyed by use? :D


We should really sue Apple. It is not hard to make a better coolling system....
I think a lawsuit is needed. This would curtail this illegal action.
Now that is some really good idea. This could change the situation. Anybody has an experience in such actions?
I'm sure that :apple: knows about this defect pretty well, but still keeps selling bad displays anyway, saying that it has 100% quality and reliability.
 
Week old 27" i5 imac and it's still perfect!

I purchased my 27" i5 imac on 2/13/11. It's been 8 days and so far so good. I must have been one of the lucky ones, having an absolutely perfect screen. I've had it on 24x7 and just did all the tests with no problems found. I almost didn't pull the trigger on this but glad I did. Of course, now that the new Macbook Pros are reportedly expected to come out this week I may end up exchanging it for a next gen MacBook. Since I don't seem to have any screen blemishes on this imac, maybe I can sell it for enough to cover the cost of a new 17" MacBook Pro? lol
 
I purchased my 27" i5 imac on 2/13/11. It's been 8 days and so far so good. I must have been one of the lucky ones, having an absolutely perfect screen. I've had it on 24x7 and just did all the tests with no problems found. I almost didn't pull the trigger on this but glad I did. Of course, now that the new Macbook Pros are reportedly expected to come out this week I may end up exchanging it for a next gen MacBook. Since I don't seem to have any screen blemishes on this imac, maybe I can sell it for enough to cover the cost of a new 17" MacBook Pro? lol

By perfect screen you mean you also don't have a backlight bleeding issue of any kind on the lower corners of the display, right? Can you please check?
 
I purchased my 27" i5 imac on 2/13/11. It's been 8 days and so far so good. I must have been one of the lucky ones, having an absolutely perfect screen. I've had it on 24x7 and just did all the tests with no problems found. I almost didn't pull the trigger on this but glad I did. Of course, now that the new Macbook Pros are reportedly expected to come out this week I may end up exchanging it for a next gen MacBook. Since I don't seem to have any screen blemishes on this imac, maybe I can sell it for enough to cover the cost of a new 17" MacBook Pro? lol

In my experience, it takes usually a few months of use for those gray blemishes/spots to appear.


Same thing: in our office we've got Apple Cinema LED display, which due to the tasks has to run 24/7 turned on, Mac Pro has SmcFanControl installed for this display. And display had still developed these black spots! So as several other iMacs. But not all of them, some iMacs run about a year, they get heated pretty well, but are still alive.

Come to think of it, I also have a older 24 inch ACD that developed the same problems. It was used as a dock to my Macbook Pro. It had its LCD replaced twice in the course of two years. It seems a common problem with the aluminum and glass desktop units. Of course my Macbook Pro do not have this issue.

There is definitely a design flaw in these units.
 
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I had major black mark issues just before Xmas, took it in to get repaired where they weren't all too happy with doing it. They eventually agree to fix it under warranty and I picked it up just before New Year with a brand new LCD fitted.

Just last week my LCD has started getting the exact same markings on the screen and I'm just a little bit peeved off. I am having to do without a machine for a week each time, and with a supposedly brand new LCD fitted, I have marks on the screen.

I bought this iMac at the end of October, end of December, 2 months later, I start getting the black markings, new LCD fitted. Now, almost exactly 2 months after getting a new LCD fitted I have the exact same problems. Will I need to put up with this every 2 months on a £2000 machine?
 
By perfect screen you mean you also don't have a backlight bleeding issue of any kind on the lower corners of the display, right? Can you please check?

I just tried to check for "light bleed" as you described and yeah, the corners do look a little brighter but it seems like one could tone that down somewhat by adjusting brightness and contrast or something? I'm not worrying much about it as it doesn't bother me and I may be taking it in for an exchange for the new Macbook Pro by this Thursday or Friday.

The fact that these issues aren't being presented until after you've had the imac a couple or three months has me rather concerned about keeping it.
 
Here's the old thread on the Apple boards, back from 2006:
http://discussions.info.apple.com/thread.jspa?threadID=734800&start=0&tstart=0

The guide I followed can be found here (pdf in spanish):
http://www.macuarium.com/cms/tienda...=com_remository&Itemid=0&id=418&func=fileinfo

Has no one else tried this, manually cleaning one of the screen's parts? (Is it just because it's in Spanish?)

I'm planning to follow that guide with hopes of success. I might be able to translate it and make an English copy. Maybe.

EDIT: Or, easier yet, let Google Translate do it. Download the PDF then choose 'translate a document'.
 
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just saying to me it looked like uneven backlighting (which goes along with all the backlight problems now). sorry.

Well I have to say that's what I thought too when I looked at them. Somewhat uneven backlighting--usually called clouding on the AVS forum which is certainly a rather common occurrence with LED lit LCD screens.
 
late 2009 27in imac i5

in case there is a law suit, i want my experience to be somewhat "documented" with the rest here. i'd purchased my late 2009 27 in. imac i5 refurbished machine from apple.com on april 16, 2010. around late july/early august of 2010 is when the blotches first began. to be honest, i'd initially thought they were part of my background image, appearing as smooth and puffy clouds, but i knew there was a problem when the background changed and the botchy pattern didn't. it has since spread half-way down the left side of my screen, and it is beginning to take root in the top right corner. i wil be bringing the computer to a mac service station either march 2 or 3, and i will report back with whether or not getting the repair is like pulling teeth.

i never game on this system, but i do regularly record and edit audio using Logic 9.

justin
 
I have had my faulty LCD replaced twice by them, but not before they accused me of being a smoker, which I'm not, and then saying the can smell nicotine off it, and that it has a yellowish tinge that is in line with smoking. Absolutely shocking customer service, but they did fix it.
 
Has no one else tried this, manually cleaning one of the screen's parts? (Is it just because it's in Spanish?)

I'm planning to follow that guide with hopes of success. I might be able to translate it and make an English copy. Maybe.

EDIT: Or, easier yet, let Google Translate do it. Download the PDF then choose 'translate a document'.

We have tried to perform cleaning as steve96815 did, but unfortunately we did not manage to open the LCD panel. The PDF in Spanish refers to older iMac model, it has different screen. I know it is doable and I have tried to contact steve96815 with no response :-(
Please follow our thread about it here
 
So, we can conclude that iMac 27" display is suckish?

Dangg .. i was planning to wait and buy upcoming 2011 iMac, hopefully the 27" in $2000 range

But after all reading here, i become so nervous, this is $2000 computer that should be able to handle anything i throw at home, and supposed to be RELIABLE without fear of something happens whenever you turn on/use your iMac

So what do you think? Should i stick with the iMac? or switch to MBP? MacMini?

My main use will be graphic design, browsing, music library and media center connected to my A/V receiver

I hate returning iMac due to display problem. Maybe i'll get myself Apple Protection Plan along with iMac purchase .. but yeah, you know it sucks to wait for repair/replacement .. even under warranty. It feels like you buy bad things
 
Has no one else tried this, manually cleaning one of the screen's parts? (Is it just because it's in Spanish?)

I'm planning to follow that guide with hopes of success. I might be able to translate it and make an English copy. Maybe.

EDIT: Or, easier yet, let Google Translate do it. Download the PDF then choose 'translate a document'.

We have tried to perform cleaning as steve96815 did, but unfortunately we did not manage to open the LCD panel. The PDF in Spanish refers to older iMac model, it has different screen. I know it is doable and I have tried to contact steve96815 with no response :-(
Please follow our thread about it here

The guide was written years ago and is not very helpful for the current generation of iMacs. As I wrote in my original post, the guide was written for the "black spots" problem on 20" G5 iMacs, and I only posted the links because the spots on the current generation look identical.

I have successfully cleaned a 2010 iMac a couple of weeks ago and believe the issues are related, but not exactly the same. While it appeared to be heat related on the G5 iMacs, this time around dust seems to be the most common cause for the spots. Once I had the panel open, all it took was wiping away the dust with a microfiber cloth. The whole procedure took about 45 minutes. Didn't take pictures, but Oggy posted a good guide, though I recommend you take it to Apple first if your iMac is still under warranty.

The thread on Apple's boards related to this issue is now on page 12 :eek:! It is really ridiculous that they still refuses to acknowledge the issue. Must be costing them quite a bit. They still seem to "repair" affected iMacs by putting in new panels when all it takes is about half an hour and a cloth.
 
Chiming in

I also wanted to document my blotches here, which are in the upper right hand corner of the 27" i7 imac I bought in mid-December 2010. I don't know when I started noticing them, but they have definitely become pronounced recently.

Just to rule out some of the usual suspects:

  • I don't game or do processor intensive graphics work.
  • I don't run boot camp.
  • There has never been a lit candle or cigarette in my home.
  • I wouldn't say it's dust free, but it's no more dusty than any other apartment, I imagine.
  • There are no significant humidity/mold issues in my apartment.

Right now I can live with it. I've got AppleCare, and feel like waiting for the time being, and hope that perhaps this issue gets resolved before I have to take it in.
 
Does anybody know if the LCD panel is designed differently in the 2011 iMac to stop this happening ?
 
Does anybody know if the LCD panel is designed differently in the 2011 iMac to stop this happening ?

Old thread...

But I've been searching and can't seem to find the answer to the question above. All the complaints I have read about are for 2009 and 2010 iMacs/ ACD's. Does this happen on 2011 iMacs?

Is the black smudge issue a given? I was planning on buying one this Christmas, but the amount of threads here, and other places, about this issue are overwhelming....
 
Does this happen on 2011 iMacs?

It didn't happen on mine, but that's not the say all 2011 iMacs are exempt from the problem.

I would guess two years down the line, it's probably not much of an issue, or you'd probably see a lot more recent posts on the subject.

I wouldn't be too worried.
 
I wouldn't be too worried. I bought my 27" iMac in Aug. 2010 and had its display replaced in Dec. 2010 for a glob of dust stuck in the LCD panel itself. The replacement LCD is flawless and to this day has no dust or black smudges.

I try to keep my iMac clean though. Every few days I wipe the top edge of the iMac where dust collects as well as the base of the stand. I like to think this would reduce long-term dust buildup inside the machine.
 
Black smudge screen failures

I have experienced the black smudge screen failure several times. I purchased a 27 inch iMac in November 2010. Within a month I noticed the cloud like grayish black defect. It appeared most prominent during boot up when the screen becomes completely white. I took the computer in, and they replaced the screen, free of charge, under the 1 year manufacturer warranty (no apple care required). When I got the computer back, it was great for a couple of months, then the same problem occurred. Again, I got a replacement screen - no charge. I got the computer back, and the screen failed again within a few months. In addition to the three screen failures, the optical drive on the DVD player failed twice. These five "major component failures" occurred within the first year of purchase, which meets criteria for a replacement unit, which Apple provided. I have had the new iMac it for one month, and sure enough... the black smudge screen failure defect is back!!! This is the fourth time, on two separate units. I have no explanation. My computer sleeps after 1 minute and hibernates after 1 hour. The computer sits in a room at 70 degrees and is not in direct sunlight. If anyone knows more about this problem, please respond.
 
Ultrasonic Humidifiers?

So, after some research, I found out that ultrasonic humidifiers may to be blame for this problem. I have been experiencing this same issue and have had the screen replaced 3 times and then given a brand new iMac from Apple after the problem kept occurring. After having the replacement for about 8 months with no problems but now that winter has come, utilizing my ultrasonic humidifiers, the problem has crept up yet again.

I'm starting to think this may be a good explanation for this problem. Has anyone else used ultrasonic humidifiers in their home or apartment and then experienced the same problem?

I will flip off my ultrasonic humidifiers, take my iMac back to Apple for yet another replacement screen, then hopefully find out if this was in fact the problem and post my findings here.

I hope the root of this problem is determined soon so others won't have to go thru my same frustrations.
 
Possible fix for gray stains?

My boss reports that he got rid of the bad, gray blotchy stains on the display of his 2009 27" iMac display by turning up his "flurry" screen saver to "many" streams, "thick" streams, and "fast" speed and letting it run without sleeping over the 4 day Christmas holiday. It remains to be seen if they will return, but it appears to at least work temporarily to help reset the pixels and eliminate the stain effect. Has anyone else had success with this?
 
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