New iMac 27inch screen flickering/tearing/shutoff

I have been experiencing some problems with the all new iMac 27inch display.
At non-fixed intervals i will get one of the following:

Screen distortion/flicker somewhere random in the screen (feels like it is more in the lower part) that looks like a horizontal bar of about 2-3inches just popping in and out of the screen.

Screen will go completely black for a second and then come back on. Sometimes 2-3 times in a row.

Somebody else already made some video-clips about these problems, I am experiencing exactly the same behaviour.

http://www.youtube.com/watch?v=SjOxlxVz5Os
http://gallery.me.com/larzy#100025

Just to not that in the course of writing this post my screen has flickered 13 times and has gone black 2 times.

iMac 27inch 3Ghz 4GB 1TB ATI 4670, Mac OS X (10.6.1)

Posted on Oct 27, 2009 3:56 AM

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4,486 replies

Feb 4, 2010 12:11 PM in response to tattoo99

Yes tattoo, it's been posted before.

I wouldn't give much credibility to those rumors, there have been plenty going around that have been disproven.

All of these 15% refund rumors seem to have originated with Mark Wilson who runs the website "Gizmodo".

While his website is generally entertaining, not much reliable comes from there. He has a bone to pick with Apple since they refuse to treat him as "special", and he is doing what he can to cause them a little discomfort.

It sure wouldn't be a bad idea for Apple customers though.........we could all make a few bucks on a deal like that. I currently have two i7's, that's good for a full refund, plus an extra $600 if what Mark says is true.

All I have to do is return them, take the cash and buy another machine, then start the process all over again.

I seriously doubt that any company, even one as generous as Apple will refund more than the original purchase price on any item. Acer sure didn't do it, Toyota won't even consider it.

Anything is possible, but I think Mark is just blowing smoke.........again.

Feb 4, 2010 12:20 PM in response to tattoo99

BTW tattoo..........

I think you were one of several posters here who were still fence sitting, waiting to purchase a 27".

If you have been following this thread since the last firmware update, it may be time to make the leap.

The fix seems to be holding up, and the i7 is an incredible machine, I don't think you will ever regret making the purchase.

Feb 4, 2010 12:36 PM in response to Jan Sampermans

Hi guys, good news!! (although I'm almost scared to say it in case I jinx myself!!)

Got my replacement 27" yesterday - and I'm pleased to report that (so far) there are no issues at all.
No flickering, no yellow screen.

The first time I noticed the flicker on my last model was when I connected the firewire and transferring my files.
This time 'round, not a flicker in sight...

So, I might be sticking my neck out a little here, but it does sound like the problem has been sorted and the new iMacs being shipped are fine...

I'm not sure what week my machine is, but the serial starts: W800
(Can somebody please remind me of how you use the serial number to identify the week number and country of manufacture?)

Anyway, I hope that this post might be of use to anyone who is hovering to buy a new Mac but is scared to make the jump (after the ongoing flickering fiasco)!
All seems fine...

(So - now that I've just happily posted this information, what are the chances of my new Mac developing a flicker??!! Lol!)

Fingers crossed...

Feb 4, 2010 1:08 PM in response to Jan Sampermans

With the great variability of the appearance of the flicker problem, I began wondering why some systems have the problem while others seem to be problem free. One thought, Apple probably has several assembly lines working on assembling and manufacturing this model. The same holds true for all those who manufacture the components Apple uses in these IMacs. I do not know how many different assebly lines this may total up to but what if one of two of the lines, or even only one or two of the machines on one line happens to be defective or poorly set up?

One scenario I would offer is a cleaner/fluxer in a wave soldering machine on one line somewhere in the system. Perhaps the flux level was low or the flux was contaminated. Some of the assemblies coming off this line may therefore suffer from cold solder joints or cross land contamination. Those particular units end up with the problem while other systems, built of other lines, work normally. The problem, if it is a soldering problem could also be poor heat control or problems in the solder alloy.

I am NOT saying that the problem is a solder problem but offering a thought as to why there seem to be systems that do have the problem while others do not. It might be a out of tolerance component used in some lines or some poorly set pressure crimper or who knows what. The firmware fix may adjust some setting so system parameters are less critical about a signal coming from the defective circuit but if the signal is excessively degraded beyond the correction range of the firmware, the problem will still come back, maybe just not as frequently.

Is there any way to determine, based on serial number or other identification which line, plant or location may have made a particular machine?

Feb 4, 2010 1:12 PM in response to Jan Sampermans

Good news... (crossing fingers) but it appears the random flickering was solved by the most recent softwared update. I've been working for 2 days straight since the update and haven't had any disruptions. Usually I'd see it a couple times a day randomly, but nothing for 48 hours. I'm keeping them crossed though. This was my first Mac and I was little let down when I started experiencing problems with the flicker, BUT the machine is awesome overall... so here's hoping the fix did the trick!

Feb 4, 2010 1:35 PM in response to Gloria M

Maryarena wrote:
Warren, thank you very much for the tips. When I update the Flickerying fix, I will disable some of the options, so it does not go to sleep. I just converted photos in Adobe Lightroom and am amazed at how fast it went!

Thanks again!


Hello Mary. You are most welcome.

Yes, these machines -- especially the 2.8 GHz Quad Core i7 iMacs -- are lightning fast!

Out of habit, I will sometimes wait for an application to open, and then suddenly realize that it already is open!

Prior to this, I was working on a 733 MHz G4 mini-tower, so you can just imagine the speed bump that I have experienced with this new iMac.

Now if Apple will just cure the yellow tinge. 😟

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New iMac 27inch screen flickering/tearing/shutoff

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