Smudge or stain behind display

Question

Level 1

8 points

Smudge or stain behind display

My flat panel G4 iMac has been in storage for just over a year and I've just recently started using it again. Prior to it being taken out of use, there were no problems whatsoever. However, when I started it up for the first time recently, I noticed that there was an area of smudging, or some kind of stain, behind or inside the screen. (Otherwise everything was fine.)

First off, there is nothing on the screen itself that can be cleaned off. Whatever it is, is behind the screen. Secondly, I think it is very unlikely that this smudge or strain came about through some kind of pressure or impact to the screen, since, to the best of my knowledge, it was standing freely without anything or anyone (except to move it) near it.

Whilst it was in storage, the iMac was moved from where I left it to another part of the room it was in. It so happened that it was placed somewhat close to a non-double glazed window (the machine was coverered). I can imagine that over the course of over a year, after a damp and miserable Irish winter, near this window, there would have been temperature variations and probably a bit of dampness.

So, my theory is that a light layer of a mold like substance formed (I guess) between the LCD screen and the backlight. I believe this is the case, because there seems to no problems with the pixels in the 'smudged' area: all colours are rendered just fine. It is just that the area in question is darkened, as if there were something obstructing or dimming the light coming from the backlight.

I suppose the obvious question is can anyone help me with this?

Is it possible to open the display, and somehow clean off this residue from whatever it is on (if my theory is correct)? It is slightly annoying, and if it can be sorted in any way easily I'd like to do it. I'm not afraid of opening up computers.

Are there any technical docs out there that detail the parts in the display, or perhaps any guides to assembly/disassembly?

Thanks in advance!

G4 iMac flat panel, Mac OS X (10.4.10)

Posted on Sep 16, 2007 3:00 AM

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Answer 1

K Shaffer

Level 8

36,022 points

Sep 20, 2007 8:15 PM in response to merlante

The cost in authorized and qualified labor to disassemble those may be a concern, but to remove the panel
from the enclosure may be very difficult; so getting any mold or condensation caused discoloration from
between the layers in a display may also be next to impossible.

The problem may actually be sandwiched between the outer layer you see and could carefully try to clean,
and the internal layer(s) of the LCD panel; and backlighted section is a professional job to get into. If the
display is so affected, the cost of repair or replacement of the LCD may exceed your budget. A known
good new or used display could be installed on the computer; or you could eventually have a tech take
the computer down to the basics and remove the display at some date, to have it run "headless" with an
external LCD as a main screen. (I suspect the LCD panel inside the iMac is not cleanable inside.)

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Answer 2

merlante Author

Level 1

8 points

Sep 21, 2007 6:04 AM in response to K Shaffer

Thanks for your response.

I suppose the real question here, if there is a wipable/removable substance between two layers of the display, is can I remove it. Like I said before, I am not afraid to have a go. But I am not going to near it until I see some kind of schematic of what is in there, and ideally (though I haven't managed to find one) an account from someone else who took apart the display.

Are there any documents available from Apple that could help me here? Has anyone come across anything that could be useful to me on this one?

Aside from that, I suppose I'll look into getting it looked at by technicians, although that would be hassle, but I know local support for apple products is thin on the ground. I also don't want to pay some ridiculous fee or be told that it would be cheaper to buy a new computer, or some other such non-solution. I have opened laptops before and have put them back together no problem. How much harder can an iMac screen be? (Except that I'll need to get some odd tool to tackle the nuts/screws at the bottom of the back of the display.)

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Answer 3

K Shaffer

Level 8

36,022 points

Sep 22, 2007 2:56 PM in response to merlante

The task of totally opening up an iMac G4 so as to remove the damaged display, can be a daunting task.
Could be called an 'undertaking' should you mess it up and cause other major problems in the computer!

There used to be places online to download the original service manuals in pdf but it was said some if
not most of them were illegally posted and were asked to be removed by Apple. So, you may find another
source for the service manuals in pdf; a few enterprising companies do offer them on a CD for a price for
the technically minded to repair their old out-of-warranty computers. There was a place which sells what
they call "recycled" previously owned Mac system software, and they had these manuals on cd for sale.

The name of the company included the word "apple" but it isn't part of Apple, Inc.
The place was called: www.applerescue.com/ and was a completely separate entity.
However, the link does not appear to work anymore, so maybe they were closed down.

Maybe an authorized tech or former tech has a copy of the correct service manual on CD; the file was
about 14MB or so, for the iMac G4 1.25 17" model. I have and used it to troubleshoot my own iMac
under warranty when the nearest service provider was unable to find reoccurring problems with mine.
Perhaps someone can give you a link to find bits of the process online, as some are still available.

Best wishes and happy computing! 🙂

PS: have you tried a generic search using words such as these, see link: 'removing iMac G4 LCD panel' ?
http://www.google.com/search?q=removingiMac+G4+LCD+panel&btnmeta%3Dsearch%3Dmac=Search+MacSites

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Answer 4

Oct 2, 2007 6:09 PM in response to K Shaffer

Hi

I just turned on my imac 23 inch that came today. I noticed in the lower right hand corner what looks like a smudge - what is worse it seems to be behind the screen. What worries me is that this is a custom build for hard drive etc. Why did apple not see this before they shipped it bothers me a bit. You cannot miss it.

My question is this something I can do without lugging this heavy thing around. Now what is bothering me is that if I return it I will be without a computer until it is fixed. Not good and I guess having everything built into one unit such as the imac is not as good as it seemed.

Advice/suggestions welcomed and in case you ask I love it otherwise.

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Answer 5

mrtotes

Level 6

11,836 points

Oct 3, 2007 7:56 AM in response to Britney2B

There aren't any 23" iMacs. Do you have one of the new 20/24" aluminium Intel iMacs?

iMac (Flat Panel): Intel iMac:
Click image to go to correct forum.

You'll get better advice in the more relevant forum.

However in your case I would simply call AppleCare. It sounds like you have uneven backlighting which is unacceptable on a new iMac.

mrtotes

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Answer 6

K Shaffer

Level 8

36,022 points

Oct 6, 2007 7:41 PM in response to Britney2B

If you bought the computer through a retail store, talk to the sales manager about exchanging it for another,
or ask what you can do with this computer that won't leave you without a working computer, since you got
it to use, not send in for repair right out of the box. They may be able to do this on-site.

And if you bought the computer through an online reseller, you should contact them to see if you have any
options that you could exercise; most have a plain policy that covers all things, and not necessarily what
you'd like it to be. On occasion, if you talk to the person who can make a determination, some businesses
can see their way to providing customer service and customer satisfaction, too.

There often is a time limit on how long after purchase you could return a product to a retail store (or by mail
or shipper if it were bought online) so to act on this in a timely manner is suggested. Best of luck!

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