Greyish Smudge marks behind the glass screen.

FOR ONE AND ALL HERE:

No one cares if there's a little dust between the outter glass panel that can be removed with a suction cup and cleaned. That is easy. If your screen has a little smudge between the outer panel and the LCD the get a suction cup take off the outer cover and use a little cleaner and wipe it clean. problem solved. THIS IS NOT what we are all griping about!!!!!

We are griping about the serious irritation of Micro fine dust/smoke particles that make smudges between the multiple layers of diffusers and the back of the actualy LCD. These smudges are what is the problem. They cannot be fixed without actually dissasembling your inner display and This is a SERIOUSLY difficult lthing to do.

Because any slight torqing or bending of the little ribbons that connect the LCD or any bending or twisting can ruin your display FOREVER. (PERSONAL EXPERIENCE HERE)

I have dissasembled 4 screens the last one just this morning. This last one is only the second time I have succeded in cleaning it without damaging my screen. And yes it will void your warranty.

Some of the newer imacs have tape around the edges of the inner LCD in an attempt to SEAL it better from particulates. These are ULTRA FINE... Here are the situations that can cause it:

1. Smoking in your home... Bad JuJu... Don't do it.

2. Your wife accidentally burns the roast... smoke in house... oops... bad JuJu once won't hurt but 3 or 5 times will.

3. You fry greasy foods a lot. Oh well this is even WORSE than smoking...

4. You have an old Oil furnace that leaks a little into the house... not enough for you to notice or hurt you but after a few years your screen is toast.

5. Humid environments....

6. Normal Dust. Unless you live in a CLEAN room and NEVER have to blow a dust buster at your computer to blow out dust you will get dust eventually in your screen as well.

7. Running your machine a lot. HEAT... If you run your machine hotter than others you will get the dust in there quicker...

In other words. It is a DESIGN FLAW it will happen to all iMacs eventually it's only a matter of time.

In my experience it happens most after the second year or so... Total of 3 iMacs and 4 cleanings now... over the last 7 years...

And for goodness sake DO NOT TAKE THE SCREEN APART unless you are willing to gamble $500 on your skills.

But can it be done? yes.... it can... I said I'd never do it again... till I did this morning...

I'm on my computer every day and I don't smoke near it. having said that my LCD TV has no screen issues and it's situated right beside the mac. a designer flaw? yes for sure.

More than this. My wife's Imac (20" mid 2007) is in the same room and has no smudges problems... but mine (27" mid 2011) has...

The down side is that yes we can all discuss our mac issues here but is apple ever going to do anything about it? I don't think so.

I think you have a bad case of the "not knowing what you're talking about". If you took a minute to read past messages it would have been very easy to see how this problems is not at all related to dust behind the protective glass screen held in place with magnets.

We've been at it for a while, it's frustrating to see somebody come here, ignore all the troubleshooting we did and just imply that we're all stupid.

Since 2008, I've been suffering iMac display issues like image persistence, grey stains, etc. My history includes five replacements of LCD panel, one replacement of HDD and one replacement of the whole iMac. Recently, I added another replacement of the whole iMac(early 2008) to a new iMac(mid-2011).

Mostly, my complaints were about image persistence, not smudge or dust, and I believe the image persistence is due to poor heating control of iMac systems at the time. Regarding new iMacs, however, it seems to focus mainly on smudge, dust, or as some people called, cloud. So, I visited an Apple store to check the new iMac. Here, I could find the grey stains even in iMacs displayed the store. The clerk looked slightly stumped and indicated the upper side of the iSight camera. To prevent dust to flow inside panel, he told me to have to tape the position as soon as I unpack the new iMac. It was on the built-in microphone to be taped! I've never noticed the mic. until then. The mic. seems to be located off the thickness of the tempered glass screen.

Then, it means that the Apple has already recognized the design flaw, but they never admit it officially. If it is true that the mic. was the cause of the grey smudge, Apple must admit the design flaw and recall iMacs ASAP!

How exactly does the dust enter the screen......?

Ultimatly it's about heating and cooling. We know from version 1 that the iMac has suffered from heat problems.

When the screen heats up it forces any air out of the lcd assembly. When it cools it ***** it inside again.

If the inside of the imac is dirty or if there is any fine electrostatic dust in your air it will be sucked into the screen as well. Since there is no direct airflow into the screen it is this expansion and contraction of air that ***** only the finest air particles inbetween the layers of diffusers.

No screen is immune to this problem HOWEVER since the imac get's hotter than other screens the expansion and contraction of air is greater. I have several other displays and fundamentally the design of the LCD pannel is the same as the imac. They do not get this problem because the temprature is much more stable than the imac. If you have ever taken these apart you know that this dust is so fine that it cannot be called dust. It is ultra fine, microscopic. It is not brought inside the screen because of blockages or fans or stuff near the ducts or microphone holes. The fans blow air across the back side of the assembly focused on the CPU memory and HD's The only way for this fine stuff to get inside the screen is by suction from heating and cooling interior to the screen it's self. The screens are NOT air-tight. They are taped up but nothing in the assembly can make it air-tight without causing other problems.

I'm on my third iMac here and this is the second one with dust behind the LCD. My first iMac was a 21'' white PPC that still has a spotless screen. The second one was a 24'' aluminum one (2008) and I noticed the dust spots after one year of use; Apple replaced the LCD screen (twice, because the first replacement had dust inside too, so I didn't accepted it and they had to replace it again); three months later, the dust was there again. I was sick of it and there was no more warranty left for this computer, so I decided to buy a new 27'' iMac thinking that this design flaw should have be fixed in the new generation of 2011. But here I am again, six months later, and the dust is covering the left side of the screen. What am I gonna do now? I'm going to have it fixed once again with a LCD replacement, and then I'm going to sell it and buy a Mac Mini or a Mac Pro, because I don't want to keep working with a screen covered with dust.

It's outrageous something like this happening in a 2,000 € computer.

Having contributed earlier and seen no great change in the thrust within the thread over the weeks since, I am wondering if the screen problem is exclusive to imacs (yes I know there is the glass factor).

I ask because several computers have emerged in recent months with similar all in one designs of the main components fitted behind the screen.

Would anyone have experience of other manufacturers of all in one type computers (as I think of them).

Yes when I eventually upgrade I'll be going to buy a mac mini but for now I'm just putting up with this crap that cost me so much money and has nothing but stress me out. I will be investing in a different brand of screen as well and hopefully I'll get a few years out of this one yet while I'm saving for my upgrade. The mac mini doesn't come with a keyboard or mouse. I have both of those new and boxed as a spare. it also requires an external DVD player if you want one and whatever other accessories it doesn't come with however it will be worth it in the long run........ I hope.

I have also purchased a used (Factory Refurbished) i-mac G5, core i3, about 2 years ago and within the warranty period had to call for service. I was lucky because the service tech came to my house, left me a loaner and took my machine in for a PCB reolacement. When it was returned, after a warm up period of about 1 - 1.5 hours, I noticed these smudges or streaks appearing on the display. I went to the website called 'I-fix it .com' and downloaded the instructions to remove and clean the glass plate and display. I think, as long as it is just dust, or dirt on the plate, if you use a good cleaning solution such as 'I Klear' from Apple, and a very soft 'Chamois' cloth, being very careful with how you wipe and polish, any one with moderate, tech skills can clean the glass plate and the front of the LCD panel.

They also have a section on how to dis-assemble the LCD, but after a quick review of the process and the fact that this was not my problem, I decided to leave well enough alone !!

It has been about 18 months since this happened and my i-Mac screen is still flawless !

Look I had mine CLEANED by the service guys and THEY told me it WAS NOT dust and THEY told me I would have to REPLACE the bloody LCD...

THEY took it apart, they cleaned the layers and they said it could not be fixed....

The people on here have all had the same stuff happen..it is not bloody dust in the layers...the LCD is damaged..it is a clear design flaw...

AND APPLE should be ashamed for not answering this issue...

@ Steve876

Finally. a sane explantion.

No IT'S NOT DUST on one occasion the 'greyish marks' had BURNT right into my LCD screen. it is a designer flaw. we may not all be technicians but we are not bloody stupid either and the more people who put it down to dust then the less apple will bother to even think about changing the design......... if they ever do.

Yes there are more than one problem here:

1. Dust between the outer glass and the LCD easily cleaned.

2. Fine Smoke Dust discoloration between the layers of diffusers in the LCD assembly it's self. Difficult to clean but possible.

3. Discoloration of the diffusers due to over heating. This usually is a brownish/yellowish smudginess that cannot be fixed without replacing the diffusers.

1 is not a problem it's normal maintenance.

2 is a design flaw due to heating.

3 is a design flaw due to heating.

Also, Cleaning the layers of diffusers is EXTREMELY difficult becuase they are not smooth. They have grooves in them like a Frenzel lens. The smoke/dust get's in those grooves and is almost impossible to get out.

I had to SCRUB each layer front and back for hours to get it back to perfect. Most people give up long before they get to that stage but I'm a bulldog. I don't give up. The other problem is if you use things like windex or amonia it will eventually yellow the diffusers. If you scrub too hard it will cause a smoothing of the surface and it will cease to be a DIFFUSER.... this will cause you to see bright and dark lines from the ultraviolate bulbs inside the display.

It appears as if it is burned into your screen it is true... HOWEVER if you had dissembled as many screens as I have you would know that it is actually a fine layer like smoke that DOES COME OFF it is not actually burned in. Unless you really try to OVERHEAT your machine this is not going to be literally burned in.

Burning in is not something that LCD screens do like normal old fashioned screens. And with certain screen savors that move the Liquid Crystal around it will go away unlike a really BURNED in screen from the old Cathod ray days when the phosphoros was actually burned off the inside of the screen leaving physical marks what were not fixable.

Just because it can be cleaned by dissassembling the LCD does not mean it's not a design flaw,