Q: New iMac 27inch screen flickering/tearing/shutoff

Could it be that there is a magnetic resonance between monitor and loudspeakers?

I, too, wondered about this....partly because I remember having this issue WAAAY back (in the 90s!) with my apple colour display (CRT) which would go through "underwater"-type wavy images at times, with no relation to what activity the computer was busy with. And of course, could not be replicated in service because once it was moved to the repair shop, it did not suffer the same interference. It turned out to be interference from a neighbouring apartment dweller's electrics , and once I moved the location of the computer/desk, the problem virtually vanished.

I know this is a different problem, but once the reports of repeated replacements on these imacs started coming out, it was something I thought of: why do some people have NO problems with their machines, and others have the SAME issues with 2, 3 or even 4 replacements? Could it be the environment that it's being used in? Could it be interference? Especially when it seems so random. Of course I also have no idea how that could be the case but well I could not help but think, that either this problem is FAR more prevalent than reported (given the repeated problems over several machines) or possibly due to the LCDs' vulnerability to environmental/magnetic resonance. I can't help but wonder if that could also explain why some monitors exhibit the noise on some machines, esp. at less than 100% brightness levels, and not others (mine runs silently). *Could it be that more machines have the defect than are reported, but that only some consumers will be using the machine in the perfect storm environment where the defect becomes apparent, either through flickering, pronounced yellowing, or noise issues?*

so far i have noticed flickering, brightness related noise, a noisy hd (the seagate 1 tb model), yellow tinge and 5 dead pixels on my isight camera. this is my second imac, the first had flickering, brightness noise and yellow tinge. the hd was quiet and i hadn't checked the isight camera. will the cable/display replacement fix the yellow tinge and brightness noise issues or does it fix only the flickering? should i ask to have my isight and hd replaced as well? yes, i am frustrated.

I got my iMac 7 days ago waiting almost two months (must have included that Apple had to look at every unit sent out after all these problems) and this one is working perfectly without any problems.

Hopefully that is a sign that Apple is starting to get this model work as it should in the first place!!!

That IS Great News. Excellent! But you could you please post what Week Number iMac it is. The Week Number is 4th & 5th character of your Serial Number. All the new People on this thread PLEASE, Post your Week Number. It's important to know if these are iMacs made this year or last. Thank you in advance.

Sure, this one was built week 52.

Used this to get all details about my baby:

http://www.appleserialnumberinfo.com

UPDATE:
Hello all, just a quick update about my week 52 machine.

It was my first replacement and everything has been perfect to date. (3 weeks)

I tried to wake it from sleep though 5 minutes ago and it wouldn't... Had to manually restart it. Kinda worried!
-Cliff

Some new information with regard to the flicker problem...

I spoke to AppleCare the other day and they decided that due to the consistent backlight twitching, dead spots and yellow tint that this week 2/10 machine is another DOA and needs to be replaced.

But here are some interesting details with regard to the backlight issue:

I decided to see if it would make a difference to unplug something else that was on the same circuit as the computer, like the external hard drive or speakers. Surprisingly, the intermittent dimming / surging in the backlight did reduce a bit.

I then isolated the iMac even further and put it on its own outlet altogether. This didn't make any difference to the brightening glitches and constant annoying subtle variations, but it did reduce the dimming glitch pretty significantly.

None of the other 27" iMacs, or previous models, showed anything like this. But it's interesting to me that this one seems so over-sensitive to normal power fluctuations. It still twitches and pulsates enough to drive me bonkers, but at least it isn't dimming quite as often, plugged into the other side of the room.

Someone else mentioned that their recent replacement was exhibiting this new kind of flicker so I thought I'd share my findings.

Message was edited by: dxgriffiths

Thanks for chiming in.
It's definately not as bad as the flickering which plagued my last on.
This isn't so much an interferance in the image, just momentary dimming of backlight.
I'm past the 14 day return so will wait until next snow lepard update which is due soon.
I doubt that will fix it but will then call AppleCare.

I'd like to hear if any others are are having this backlight dimming issue.

dxgriffiths & chris_vav, What week number iMac do you have?

So 2 good Week 52's in a row. The Week Numbers are important as to see if the latter weeks are an improvement. Thank you.

# 4 goes back........

This guy sure deserves a spot on the unluckiest list, but his issues are all different.
#1 .......loud fan
#2........1 dead pixel
#3........2 dead pixels
#4........flicker

I wasn't aware that anyone, Apple included would issue a replacement, or a repair for a couple of dead pixels.

IMHO a Dead Pixel is like one of the worst things that could happen. Even One.You'd be staring at thing for the rest of your life!

It just takes a little searching around to find a fix.

My brothers monitor on his windows box had three or four dead pixels. He found some wallpaper that blended with them, never noticed them again.

Most manufacturers consider several dead pixels acceptable.

Obviously Apple does not, otherwise they would not have replaced the machine for a single dead pixel.

Guess that's good to know.

pazuita wrote:

I wasn't aware that anyone, Apple included would issue a replacement, or a repair for a couple of dead pixels.

Interesting indeed. A few weeks prior to ordering my 27" i7 iMac -- which still hasn't arrived after NINE WEEKS now -- we purchased one of the last of the 24" iMacs. It's a beautiful machine. The only fault, other than the fact that it is sometimes slow at recognizing and mounting DVD's -- sometimes even requiring to eject the DVD and insert it again -- is that it has one dead pixel.

Naturally, being one who demands perfection, considering how much we spend on these machines, I mentioned the dead pixel to a store employee. Their reaction was "Sorry...anything else?". Although I didn't ask, it was obvious from their attitude that they were not inclined to replace the machine due to one dead pixel. Had the dead pixel been in the center of the screen, I would have insisted on a replacement.

For the 27", the policy (as far as customer reports and leaked internal documents go) is for 11 dead pixels, 9 stuck pixels, or if you have a combination of both then a total of 16. That's the requirement before it's considered a mandatory swap-out.

The official line, such as it is, says that some anomalies are to be expected, but doesn't specify how many.

Personally I think that "in spec" dead and stuck pixel counts should be included with the actual SPEC, and not kept secret until some poor ******* notices. How fair is it to find out after you've bought something that there's a known margin of defectiveness on a key feature? I mean, fair's fair. At least if you knew beforehand you could make an informed consent.

16 pixel anomalies certainly doesn't resonate with my understanding of the term Ultimate. But that merely highlights the dual nature of the failure in this case: out-of-control hype in the marketing, and a lack of quality to back it up.

Current machine is a week 2, 2010 build.