Greyish Smudge marks behind the glass screen.

Well, to be fair, this is probably why the sealed the LCD casing in the new iMacs. They problem we're having with the last generation shouldn't even be possible on the new ones because the LCD and glass (or probably more accurately, plastic) are fused together into a single entity. Nothing can get between them, so this smoky crap won't be able to form.

You need to actually talk to someone and request in home service. It's covered under AppleCare. Naturally Apple doesn't want to pay for someone to come to your house. The technician's that came to my house weren't even listed on the website. They may try to persuade you to haul it somewhere but just say no. It's heavy and bulky and that's why I paid for the AppleCare so that I didn't have to lug this thing around. And especially with this problem. I have had my screen replace 3 times and then a new Mac as a replacement. I still have the same issue but it's not as bad. I've had it for over a year and it's getting close to time for a new LCD. Good luck. Stick to your guns.

Sorry Jason close but no cookies regardless of depth/space between LCD to display safe cover on previous model iMacs the problem acknowledged is solely a build defect. It wasn't actual smoke or dirt that occurred but heat leaving the only conclusion that bad LCD's LG if I'm not mistaken was what created a smoke image. From tedious time consuming investigation of the matter Samsung LCD model iMacs had no problems but then again I could be wrong anyway it's a very notorious upset for those who purchase with intent of holding resale value and look to upgrade at a further point.

Generally you buy materials at top dollar to prevent having to buy the same object twice , thanks apple, thanks a lot.

P.S. For the record I currently own a 2.3 i7 rMBP, iPad 3rd WiFi 64, iPhone 4,that all serve a purpose. The thing about it is you're always going to have pros and cons thats life. So the iMac that we are referencing which regardless of supposedly being the best iMac build ever had no pros just cons.

And just in case you've never seen my post ill say it once again if you own this model iMac sell it if you can , Godspeed.

Can't tell for sure what you're trying to say since your English isn't all that great, but I never claimed it was anything but a defective design. Either way, it looks like a defective design that's been acknowledged (at least internally) and fixed in the late 2012 models.

For my 3 repairs, it was not that heat damaged the LCD, it's that heat caused water in the air to condense between the LCD and protective platic layer in front of it, or that the fans forced dust between those layers. This is a single assembly in last generation iMacs, but the edges are not sealed so contamination can enter. These layers are typicalled sealed in other devices, and the fact that iMacs have fans pushing air around inside isn't helping matters.

Indeed, someone even came up with a process for cleaning inside the display yourself, provided you've got the nerve to bust open the machine and start cutting on your LCD to break it apart: http://forums.macrumors.com/showthread.php?p=11976152

There's even a video of the process, showing the contamination inside the LCD: http://www.youtube.com/watch?v=2zHzNC38U8s

I don't know if people who have displays that change as the machine heats/cools have the same issue or just a related one, but the vast majority of the posters in this thread describe something like the above. Apple even admitted to me this was the case, but eventually simply blames it on your environment rather than own up to it being a design fault.

"Indeed, someone even came up with a process for cleaning inside the display yourself, provided you've got the nerve to bust open the machine and start cutting on your LCD to break it apart: http://forums.macrumors.com/showthread.php?p=11976152

There's even a video of the process, showing the contamination inside the LCD:http://www.youtube.com/watch?v=2zHzNC38U8s

I don't know if people who have displays that change as the machine heats/cools have the same issue or just a related one, but the vast majority of the posters in this thread describe something like the above."

I get so sick of seeing this....

the vast majority don't have the behind the screen issue...they have an issue where it CANNOT be cleaned

I had mine taken apart by Apple and told I needed a new LCD ...COULD NOT BE CLEANED came back with same marks...had the same confirmed by others on this thread

NO apple care SOOO

would NOT replace at the time

won't replace now

Australian/NZ Apple says this thread holds no credibility & won't recognise issue

Well, part of the confusion here is that Apple as a general rule doesn't repair anything. If you take it to them, they'll definitely replace it. That's doesn't mean it *cant* be repaired. It's definitely not something we should have to do, but it does work.

If there's a problem with a part that has its own part number, Apple will replace it rather than attempt repair. This actually a good thing for their customers, but it certainly does not imply that it's impossible to repair this problem. They will wipe down the front glass of your iMac, but this is INSIDE the LCD assembly. They will not attempt to clean it.

The fact is, for people like you outside of warranty and with no other options, it can be a good solution if you're handy.

I don't get that you don't get what I am talking about....APPPLE told me it cannot be repaired...they tried ..it must be replaced BUT I must pay for it...

IF I PAY $600 for a new LCD screen they will replace it...do I want to replace what should be done for free and will need to be done multple times...what do you think???

it CANNOT be fixed with the take the screen off and clean i solution...

Ha hilariously I received feedback displaying he couldn't understand because of my unestablished grammar (english)and yes I was tempted to respond but, I thought to myself obviously this guy has to be referring to sometjing he knows nothing about or, just plain in the background shouting upfront.Everyone attached to this blog is dealing with a LCD that isn't permanently unfixable unless replaced 65 pages later you would only assume if it wasn't a epidemic one the genius posting would have shared it by now but Im only stating what's obvious to all. ? If what are you refering to as LCD having personally entered this model iMac for operation and I see know ordinary consumer in there right mind trying to do anything other than wipe the smudges away which you can't because its inside the actual LCD ever hands on other he say she say YouTube medics attempted to repair it yourself exactly as he mention at about 700 I wouldn't waste my time that's money that could be compiled to obtain a different machine your so bright to live backwards is evil ha

That was exactly the point. Apple does not repair LCDs, so it stands to reason they will say they won't repair it. Taking off the glass and cleaning does not help because, like I said, the contamination is IN the LCD. The video and the guide explain it pretty well. You have to completely disassemble the machine to do it, though, so it's definitely not easy. That said, it's been posted a couple times in this very thread, and others have had a lot of success with it. Every so often someone who's been here awhile reposts it in case it helps out someone just stumbling across this.

Like I said, if you're out of options, it's worth a shot. Maybe you were skeptical because you thought I was just suggesting taking off the front glass? Not sure. If you're not comfortable doing it or don't want to spend your time on it that's one thing, but the process definitely works.

oh..I am very sorry about thaving attitude toward you and thank you for persisting...I have been on this thread numerous times and this is the first time I have had it explained that it is repairable but Apple just won't do so...

I also noticed that a few people showed how to clean the panels inside the machine...however, numerous others then came on to point out that there is actual damage on the panel that is not repairable...

so there has been a split in what people think is wrong with the machines...

given my experience w Apple saying could only replace (at my cost) I concluded the obvious..made the wrong inferences.

so...going with the idea that we can do the suction cup method for the glass front and then get to the LCD inside, aside from being complex and risky...it is a temporary remedy??? the smudges come back anyway?

I am not a photographer or anything but am ****** at having paid for a broken promise...

thank you again

Judith

No problem. I know tempers are high because Apple won't acknowledge their mistake.

There do appear to be two similar but different issues in play. One is where a smoky discoloration appears on the screen and is permanent. The other has a similar symptom, but is affected by the temperature of the machine. The former is the type that can be fixed through cleaning. The latter seems more like actual LCD damage to me, and to my knowledge no one with that issue has attempted a disassembly to determine if the process would also work for them.

That said, you are exactly correct. It isn't a fix, but rather a temporary remedy. If you were essentially having your LCD replaced every year like I was, you'll have to perform the disassembly/cleaning every year.

Hopefully stevenby's comment shows Apple's stance on this issue is changing. I've had a number of Apple computers, and this was the first one I've been truly disappointed with. I sold it and got one of the 2012 models with the fully-sealed LCD assemblies. You get one more chance, Apple...

Mattand,

Unfortunately, for your disappearing/reappearing case I'm saying we're not sure. To my knowledge, no one who has the disappearing/reappearing smokiness has ever tried the LCD disassembly. Once more of these start having their AppleCare expire, I'd expect we'll have more people trying to fix it themselves rather than shell out $600 to Apple for the replacement. If you do give it a shot, be sure to let us know how it turns out. If there's anything I can do to help, let me know.

Sorry I don't have better news for you, though. You guys are in a little bit more uncharted territory than those of us with the static smokiness.

Jason

Jason,

Appreciate the feedback. This is actually an Apple-replaced LCD. I managed to get them to replace it out-of-warranty with a polite but firm call to Customer Relations in Cupertino.

The timeline is as follows:

Oct 2010: Purchase 27" iMac

Oct 2011: Dont' purchase Applecare with the logic "Eh, I've never had a problem with an Apple desktop before. What's the worst that could happen?"

Nov 2011: Worst happens. Notice smoke/water stain on right hand side of monitor. Apple replaces it out-of-warranty

Nov 2012: Stain has returned, but comes and goes. iMac goes in for HD recall. Stain disappers for several months, but eventually resurfaces.

I'm wondering if the techs at the Apple Store cleaned the LCD while they had it apart for the HD swap. I'm debating about pulling apart to try to clean the LCD since it's out-of-warranty, but it's definitley not for the faint of heart.

To be honest, the path of least resistance is to get an external monitor and use that as my main one. I'm not wild about this, but yanking apart the iMac is really not something I'm dying to do. I will definitely think twice before making another iMac purchase.

Moral of the story: If your Apple product has a built in screen, ALWAYS get AppleCare.

I took apart a 2010 27" iMac fully to investigate the issue. My experiences are recorded earlier on in this discussion.

To cut a long story short, it's not user serviceable and there isn't any magical dust or dirt to clean up. Neither are there traces of glue residue inbetween the substrate layers. It's a rather serious fault relating to the design of this particular LG panel.

I no longer use an iMac for this very reason.

My iMac was very badly affected by this problem, there was nothing that could be done except replacing the entire panel. I simply didn't have time to enter into a long and protracted series of trips to an Apple reseller for parts. I bought a different computer.