Greyish Smudge marks behind the glass screen.

is that what happened to mine? perhaps it was getting hot or somthing... I don't really have any technical knowledge of these things. and i don't know what a ZIF type is (nor do I need to! 😉 ) all i know is it is no longer overheating - that was worrying me the most. but thanks.

I saw a ton of these grey marks behind my screen today and this thread popped up. Mine seems to be far worse than many others on here.. I tried taking pics but I can't seem to get it to show up right but it's quite bad. The entire right side from top to bottom, from the edge of the pane to about 4 inches in is grey, and then on the upper left hand of the screen there's a huge splotch of grey as well.

No apple care. My last imac had screen problems too, now this. Seems this thread was started years ago so it's not a new problem.

Very unhappy customer.

I had this grayish problem a few months ago on my new iMac. Took it in and they replace the front glass (which is made from hard plastic). Tech said it was easier to replace the front glass than it was to clean off the smudges (which they probably couldn't). It was under warranty. The cost not under warranty would have been $79 USD.

On the new iMac's it easy to remove the front panel glass. Not suction cups required. Just place your finger nail at the top of the screen and pull.

David, for many people it isn't a matter of cleaning a sheet of plastic. We're talking about a design fault inside the actual screen. That is, there is nothing to clean, the fault isn't caused by 'dirt'.

yes we know about this...but you may not be aware that the problem we are speaking about isn't able to be cleared away by such treatments...I for instance took mine in and they cleaned the screens but it made NO DIFFERENCE whatsoever...I was told it was not dust but some sort of damage to the LCD screen, and it would cost 600 to replace...

others have the same experience

Vectorkraft wrote:

David, for many people it isn't a matter of cleaning a sheet of plastic. We're talking about a design fault inside the actual screen. That is, there is nothing to clean, the fault isn't caused by 'dirt'.

The original posting is talking about smudges on the inside of the glass panel. Some people are having problems with the screen and some the glass panel. Some people may think it's the screen when it's the glass panel.

Not everyone use their computer in the same manner therefore it is logical that not every unit develop the same problems.

None of the smudges I have seen are identical and they don't always correspond with the location of heat sources (GPU etc). This indicates that overheating cannot be much more than a factor, if it is one at all. The LCD smudge issue is not exclusive to the iMac. Not all LCD models develop them either.

There is too much conjecture over this.

Regarding to the image I posted yesterday (page 56)... Today when I turned on my iMac, I didn't find these smudges..... So I would assume, they appear on my screen only when all processors become too hot.

okkk so i had these smudges on my screen for like a couple of months. So what happened though, i went away for a few days and decided to turn off my imac for those days. Keep in mind i hardly ever turn off the imac, i always put it to sleep.

To my surprise when i came back, almost all the smudges were gone. I had some on the top left corner and also in the middle of the screen. Then i went away for a whole week last week which again i turned off the imac for that time, today there are no more smudges. Really strange but very happy. Perhaps they will come back after it gets too hot? But for now it's been great. I will try to turn it off completely once a week and see how that goes.

Thing now is, i was thinking of bringing it in since i'm still under warranty until November, but now we no longer see them. Hopefully they won't be back.

I have seen the same thing for the past year but ignore it to my best but as of late I am having random power cycles. So the two items brings me to beloeve that there is a bigger problem at hand.

The iMac 27 inch top right of the screen has the power supply and the video controller on the very far right. The grey smudging is not the glass. It is very likely a damaged LCD from heat from the power supply and perhaps the video controller. I have a temp gun that I use for work and I was able to shoot the screen in areas and found the temp readings on the top right were much higher that makes me think that there is a over heating issue.

This is a major problem and I would hope apple would step up and make it right. I am taking my imac in this week to have it looked at in more detail. I will take it through the process with apple but I am going to demand that I have a new power supply and video controller along with an LCD.

With how many posts that are experiencing the same issue it would stand to reason that there is a heat issue damaging LCD.

I love the iMac, especially the later ALU editions. However, my 24-inch, 2008, is now a bit over 4 years. Within the 3 year Apple Care period the screen was replaced 4 times for this issue. Now, a year after the last replacement the smudge is back, larger then ever before and a slightly different "color". Apple stated also "environmental factors, unique to my placement" to be the reason for the problem, but I have had no problems with any other monitor in the same room, on the same desk. As many have stated before me, I believe it to be a combination of the heat buildup and a sensitive white backlight diffuser. The screen now is virtually useless for the photo editing it was initially bought for, and will probably end up in the kids room.

While I've mentally written off this 2800 USD BTO 24" iMac, I am very wary to buy an iMac replacement - is this LCD screen issue solved in the newer models?

I already have a MacMini hooked up to my TV as a media center, works fantastic, but not sure its suitable for my needs on the desktop. The Mac Pro, might be the way to go to avoid these iMac specific smudges but will be (too) expensive.

I miss something between the Mac Pro and the Mini, maybe similar to the old G4 Cube for some expandability and customization...

...or what...???

The problem was not solved in later models (see my earlier posts), in fact Apple refuses to acknowledge it in the first instance. It's a very sad state of affairs to be honest.

I wouldn't buy one again, £2,000 is just too much for a computer that can't seem to last the course.

Judging by the quality problems of their other recent products, this is what happens when products are made in third world sweat shops.

My 3 rd LCD and as javabean252 correctly has identified the heat source is the iMac itself damaging the LCD. I am going to get it replaced since I did not buy a product that self destructs over time by design!

I have had the same problem over the last two years with my 24" I-Mac. I have had some success with a program called SMC Fan Control. By regulating the speed of the cooling fans, I have found the issue is greatly reduced. At first it went away completely however lately I have needed to increase the fan speed to keep it at bay.

Good Luck

I'm going to try your technique of Fan speed. At what speed have you set them up ?

I'm highly disapointed by Apple on that one. LG display in a £2500 machine and failing after 2 years ? Doesn't sound really good !I have a lot of those marks now and It start to blur the display which is rather annoying.

I haven't tried to take it back to an apple store yet but as I can see by the previous post it looks like a default from the design and Apple is litterally ignoring us and trying to avoid a massive product call back. But if Honda has just recalled one of their car after a couple of years, I'm sure that in good hands, Apple could be forced to admit the fault and recall the faulty Imac display.

FIngers crossed but as I can see, there is already 59 pages of un-happy customers with this topic and apple hasn't make a move.