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

atlatnesiti wrote:
My wife has 27" C2D iMac with NO flickering problem - purchased on second day of release

I'm jealous!

Jan... please close this thread and start the new one, there is to much crap going on...
Start the one please - "Are the replacement iMacs Flicker Free?"
Hopefully this thread will NOT include "Bluebermuda"...

Message was edited by: atlatnesiti

Well I have followed this thread since its inception....have returned a few 3.06's then got the i5 on thursday...no problems yet (yes the 3.06's has dead pixels...yellowish tinge...and the last one had the flicker). After carefully examining a lot of posted info on here and doing some brainstorming of my own...I am wondering this - Could it be that the minidisplayport and the ATI graphics drivers are having some sort of conflict? The 27 inch is the only model that accepts an input from another device, I am wondering if this somehow has some sort of driver issue that is causing the flicker blackout problem. Many posters have mentioned that in windows 7 via bootcamp they had a hangup toward the end of the installation attributed to the computer wanting to display on an external display rather than the onboard one. Is it possible that there is a driver issue causing the iMac to conflict with the minidisplayport's ability to accept an input therefore occasionally causing "confusion" in OSX? Just a thought...

Message was edited by: Dicebier

Dicebier wrote:
Could it be that the minidisplayport and the ATI graphics drivers are having some sort of conflict? The 27 inch is the only model that accepts an input from another device, I am wondering if this somehow has some sort of driver issue that is causing the flicker blackout problem. Many posters have mentioned that in windows 7 via bootcamp they had a hangup toward the end of the installation attributed to the computer wanting to display on an external display rather than the onboard one. Is it possible that there is a driver issue causing the iMac to conflict with the minidisplayport's ability to accept an input therefore occasionally causing "confusion" in OSX? Just a thought...

Anything seems possible at this point!

My feeling is it's the power supply. I say that because, after 3 days of experiencing no issues whatsoever, yesterday they started again, only this time with the addition of the screen blacking out, which was new for me. Anyway, it didn't show any sign of abating; the flickering was all over the screen, so eventually I shut it down, switched off at the mains for 30s, then rebooted. I've been symptom free ever since. As an interim solution it seems to work pretty well - but it can start again at any moment of course. I'm quite prepared to give Apple a fair chance to put this right, even if the replacement has to go back too. Providing I can continue holding onto my current machine until I receive a faultless product, which is what I'm doing now, I may have to play this game for a while.

Mactoubib,

I just received my i7 yesterday and I had an instance of the flickering when I awoke it from sleep. Upon restarting the computer the issue was gone. I then used it for one session for several hours without a problem. I then shutdown and used it again later the same night for several hours without any problem at all. I did download the latest os x update (10.6.2) and my ati extensions are all up to date now (1.6.6.25(7429)). My question for you is have you seen this occur again at all after the latest extensions are installed? This is my first mac and I really hope I don't have to send it back.

Jay92323 wrote:

I just received my i7 yesterday and I had an instance of the flickering when I awoke it from sleep. Upon restarting the computer the issue was gone. I then used it for one session for several hours without a problem. I then shutdown and used it again later the same night for several hours without any problem at all. I did download the latest os x update (10.6.2) and my ati extensions are all up to date now (1.6.6.25(7429)). My question for you is have you seen this occur again at all after the latest extensions are installed?

Jay, your i7 came with 10.6.2 and all the latest extensions already installed, therefore there was nothing for you to update. If you've seen flickering, even once, then you have a problem similar to the rest of us. As far as I'm aware, Apple are still replacing machines rather than saying be patient and a firmware fix is on the way. No-one likes to have to send their lovely new machine back.

Jay92323 wrote:
Mactoubib,

I just received my i7 yesterday and I had an instance of the flickering when I awoke it from sleep. Upon restarting the computer the issue was gone. I then used it for one session for several hours without a problem. I then shutdown and used it again later the same night for several hours without any problem at all. I did download the latest os x update (10.6.2) and my ati extensions are all up to date now (1.6.6.25(7429)). My question for you is have you seen this occur again at all after the latest extensions are installed? This is my first mac and I really hope I don't have to send it back.

Yes! I haven't had any problems for about a week and thought the updates had sorted it out. However, I then plugged my external hard drive in to transfer some video and pics and they machine is like it has turrets or epilepsy. The screen hasn't split with the dock half way up the screen this time though!

Schwa72 wrote:
The problem seems pretty widespread to me, despite the lack of scientific rigor in this "poll." I've yet to see anyone post who's owned a 27" iMac for more than 10 days who hasn't had the display problem.

You're really surprised at that?? If I had gotten an iMac with no problems, I wouldn't be too motivated to spend my time on these forums! Apple has probably sold hundreds of thousands of these machines and there are probably a few dozen issues reported here. There's no way for us to confirm that is affects any significant percentage of 27" iMacs.

I, for one, finally got Apple to agree to exchange my iMac after 3 weeks of troubleshooting over the phone. I'll try to remember to come back here after a week or so and post if I haven't had any issues, but maybe I'll forget because I'm so satisfied with my new machine and just want to enjoy it rather than live in the past

I have a 27" i7 4GB of RAM and a 1TB HDD!(For 3 days)
I had not had any issues until this morning when I turned my mac on, my office gets rather cold sometimes and last night it was very cold outside, so when I turned my iMac on it was 16 degrees Celcius!! I had about 5 instances of flickering but I put them down to how cold my mac was it's now running at 35c and I haven't had a single problem since the heat boost and PRAM reset.
Can anyone give me their opinions on whether the cold could have caused the issue in my case? I really don't think it's a faulty mac as the flickering was very minor just a band 2" high across the screen! Any help would be very welcome

Thanks, Jimi

Hello

My story...

1.Had my first imac c2d 27" 3 weeks ago..had flickering -> called apple an had a replacement.

2. My second imac had massive bleeding (yellow tint) + bad dvd drive -> called apple an had a replacement.

3. Just had my 3rd imac yesterday. It is twice as fast as before (startup really fast) and it had no flickering yet. I did several benchmarks + heavy photoshop , indesign an illustrator editing as a test...still no flickering... i hope the problems with these new imacs are solved.

If anything changes.. i'll let you know.

Anything from Apple on this? My new i7 iMac was fine for like a day and then I started getting the flashing bar and display going black. Is the consensus that it is hardware or will a software update fix it?

I can say that the top rear of my unit gets EXTREMELY hot. So hot that I can't touch it for long. Is that normal for iMacs? Is the video issue maybe linked to a overheating issue?

Message was edited by: Patrick Seguin

This is normal... the imacs have an internal adapter (mac mini has a seperate one) and it's situated at the left top. So.. if it gets hot, it's normal i think.

My problems seem to have gone away completely.

I have to wonder how common this is. In this thread, it seems that most people who get a replacement get a second bad model - implying that it's common - yet there is no word on the bigger Mac sites about this problem - implying that it's rare. Something is strange here. I think that it's software related after all, and that everyone who has a repeat failure has it because they reinstall from a backed up installation. If you look around, you will find that some hardware-specific settings are transferred over when migrating.

Has anyone with a serious problem done a fresh installation, with no migration of old data and settings? Did that help?

As for heat: The GPU can be 90°C, and the CPU can be 65°C when working hard. The air leaving the machine will be about the same temp. 90°C in particular is quite hot, so I think that that is quite normal.

PixelJimi wrote:
I have a 27" i7 4GB of RAM and a 1TB HDD!(For 3 days)
I had not had any issues until this morning when I turned my mac on, my office gets rather cold sometimes and last night it was very cold outside, so when I turned my iMac on it was 16 degrees Celcius!! I had about 5 instances of flickering but I put them down to how cold my mac was it's now running at 35c and I haven't had a single problem since the heat boost and PRAM reset.
Can anyone give me their opinions on whether the cold could have caused the issue in my case? I really don't think it's a faulty mac as the flickering was very minor just a band 2" high across the screen! Any help would be very welcome

My house is always hot and I have had issues since day one so don't think it is cold or temp related.

Thanks, Jimi

Gille_Belgium wrote:
Hello

My story...

1.Had my first imac c2d 27" 3 weeks ago..had flickering -> called apple an had a replacement.

2. My second imac had massive bleeding (yellow tint) + bad dvd drive -> called apple an had a replacement.

3. Just had my 3rd imac yesterday. It is twice as fast as before (startup really fast) and it had no flickering yet. I did several benchmarks + heavy photoshop , indesign an illustrator editing as a test...still no flickering... i hope the problems with these new imacs are solved.

If anything changes.. i'll let you know.

This is exactly why I have kept a hold of this faulty beast and am helping the Apple Support guys try to work out the problem. This is my first iMac and I want to have one so am really keen to get the problem sorted and then switch my beast for a new one. No value in me switching until they solve the problem (it is a minor hinderance and a major hassle getting it swapped {I am 80 miles away from the nearest shop}).