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"Dead pixel" that moves

N

NeonBible

macrumors member
Original poster
Jun 26, 2012
87
1
I purchased a 27" iMac late 2012 in April. The first one had a dead pixel, so I returned it. The second one had a dysfunctional disk, which made it crash every 10th—15th minute (also after a clean install). I returned it, too. My third iMac had a dead pixel — that's what I thought at least. But I decided just to keep it, although I hate dead pixels. It was my third iMac after all.

But, as it turns out, I noticed today that the "dead pixel" moves around depending on the viewing angle. Technically, it therefore can't be a dead pixel.

So, is it just dust under the glass? And is there anything I can do to remove it?

Edit: Added two photos. Notice how the black spot is moving from below the "u", and then to below the "o", depending on the viewing angle.
 

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I have that on my 7 year old Cinema Display 23" Alu.

It wasn't there, but after I moved and set up the rig again it appeared, around same place.
I think it's a hole in the background light, but I'm not sure, it sits about 2 mm underneath the screen itself and, as you describe, "move".

no idea, but since yours is new I would have it replaced.
 
Thanks for reply. About the hole in the background light, I don't actually think that's the reason — at least for my display. It's a black dot just a fraction of a period. It's the same size as a pixel — just a tiny, little dot. I've had dust on the surface of the display multiple times, that I've thought was a dead pixel, which I could just remove with my finger. This one looks exactly like that, but it can't get removed.
 
It's definitely dirt. However that amount of paralax shift would appear to indicate it is far infront of the LCD itself. I know this sounds daft, but are you 100.000000% sure it's not dirt ON the screen. Have a really thorough go at cleaning it. I would even try a razor blade myself, but you may not want to do that. There was some other guy came on here a while back with a similar problem and although he was sure there was nothing on the screen, he later found that was not the case and he cleaned it off.
 
Maybe it is a small bug, I know it sounds funny but it happened on my work monitor (Dell). One day I saw this small black dot about the size of a period and I knew the dot was moving around, not very far mind you. So I pushed on the monitor near the dot it and it started running all over the place. I pushed on it and now have a dead bug that looks like a dead pixel!!
 
I had a 2011 iMac which had the same problem.

The service dept offered to remove the glass and clean it but that just seemed like a way to introduce even more dirt since it wouldn't be done in a sterile room.

I just returned it
 
I've already returned it twice, so I didn't want to be a douche this time. But, as you said, I can also send it to service and get the glass cleaned. I think it'll be worse by the fact that it won't be done in a sterile room, though.
 
NeonBible said:
I've already returned it twice, so I didn't want to be a douche this time. But, as you said, I can also send it to service and get the glass cleaned. I think it'll be worse by the fact that it won't be done in a sterile room, though.
Click to expand...

It's not like the 2011 iMac mate. The glass doesn't come off and it can't be cleaned inside, at least not without return to factory.

They either replace the screen or the iMac or you put up with it.

That said, I have you double, triple, quadruple checked the dirt is not on the outside. If yes, I'd check again.
 
Chippy99 said:
It's not like the 2011 iMac mate. The glass doesn't come off and it can't be cleaned inside, at least not without return to factory.

They either replace the screen or the iMac or you put up with it.

That said, I have you double, triple, quadruple checked the dirt is not on the outside. If yes, I'd check again.
Click to expand...
I have 1292ruple checked it since yesterday, and I think it's 99.9 % safe to say it's not on the surface, unfortunately.
 
NeonBible said:
I have 1292ruple checked it since yesterday, and I think it's 99.9 % safe to say it's not on the surface, unfortunately.
Click to expand...

Sorry to hear that.

My first 2012 iMac had some crap behind the screen and I RMA'd it. Here's the interesting thing though. For the couple of days before I decided to RMA it, it drove me bonkers, I couldn't stop looking at it and I thought I would never be able to forget it.

Then, after I had contacted Apple and they had agreed to replace it, I kept that iMac for another week before the replacement turned up. Apple said no problem - continue to use it until the replacement arrives.

During that week, I totally forgot about the dirt. It was right above the dock and easily visible - much worse than yours. But mentally once I had stopped worrying about it (in my head it was not my machine any more), it became a complete non-issue. A bit like if you use a public PC at an airport or something - it's just a tool to use and you are really not bothered about the fingerprints on the screen or whatever.

I would really just try to forget about it if you can. After a few day/weeks I reckon you will never notice it or think about it.
 
Chippy99 said:
However that amount of paralax shift would appear to indicate it is far infront of the LCD itself.
Click to expand...

Before you spend ages polishing the glass to try and remove the speck of dirt, I should point out that whatever the problem is, is definitely BEHIND the LCD (see attached explanation).

I suspect it's dirt on the backlight.
 

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Chippy99 said:
Sorry to hear that.

My first 2012 iMac had some crap behind the screen and I RMA'd it. Here's the interesting thing though. For the couple of days before I decided to RMA it, it drove me bonkers, I couldn't stop looking at it and I thought I would never be able to forget it.

Then, after I had contacted Apple and they had agreed to replace it, I kept that iMac for another week before the replacement turned up. Apple said no problem - continue to use it until the replacement arrives.

During that week, I totally forgot about the dirt. It was right above the dock and easily visible - much worse than yours. But mentally once I had stopped worrying about it (in my head it was not my machine any more), it became a complete non-issue. A bit like if you use a public PC at an airport or something - it's just a tool to use and you are really not bothered about the fingerprints on the screen or whatever.

I would really just try to forget about it if you can. After a few day/weeks I reckon you will never notice it or think about it.
Click to expand...
Your advice is truly great! It's all in the head, really! The spot is barely there, but still I'm whining like a little b**** about it.

Your story is identical to the first iMac I got in April. It also had one dead pixel, and it drove my crazy. But when I knew I would get it replaced, I didn't even notice, nor care about the dead pixel because then it wasn't "my device".

Truth be told, I didn't really care about the tiny, dark spot on my display after the two first weeks. Then I just used it as usual, and it was "perfect" until a friend of mine began to ask me about the dead pixel last week. Then I got reminded that I had a dead pixel on my 27" iMac.

All in all: Thank you for putting it in a new perspective! :)

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Parkin Pig said:
Before you spend ages polishing the glass to try and remove the speck of dirt, I should point out that whatever the problem is, is definitely BEHIND the LCD (see attached explanation).

I suspect it's dirt on the backlight.
Click to expand...
Thank you! Great explanation. Now I won't wipe it in hours, like I did yesterday.
 
Parkin Pig said:
Before you spend ages polishing the glass to try and remove the speck of dirt, I should point out that whatever the problem is, is definitely BEHIND the LCD (see attached explanation).

I suspect it's dirt on the backlight.
Click to expand...

You are correct. My mistake.
 
Parkin Pig said:
Before you spend ages polishing the glass to try and remove the speck of dirt, I should point out that whatever the problem is, is definitely BEHIND the LCD (see attached explanation).

I suspect it's dirt on the backlight.
Click to expand...

I was getting ready to make the same reply as yours... but I would not have used the graphics... which makes it obvious. Very nice job!

/Jim
 
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