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

I am very angry at Apple. I am on my third machine and still, not a word from Apple. It started flickering right after boot.

This is the fist Mac I bought first hand. I bought my first Mac, a Core 2 Mac, from a friend.

I was on the phone with Apple AGAIN and he answer in the tone of: Don't worry, there are problems with a very very small potion of the Core i7 iMac.

All I want is for Apple to say: There are problems with the new iMac; don't worry, we are on top of it and will ship you a working machine soon.

Since Apple is keeping silence I am getting a refund.

I love Windows 7, but having Snow Leopard would be a good addition.

I wouldn't be using an iMac after all. It is a shame this is my first post and I have to say this.

Well I am typing on my new Core i7 PC.

All Apple has to do is admit that there is a problem and I will keep. Hurry up and say it before I ship it back.

sparkie1984 wrote:
oh right, do you have firmware update installed?

just seems that it sits so hot all the time

maybe you got a good one!!

what week are you?

Week 47 (latest firmware) and YES I have a "good one"...

Message was edited by: atlatnesiti

im a 48!!

just wish i didnt have the tinge (its not terrible, but slightly noticeable)

Today I got the flickering issue on my 27" iMac, it started with a few tenths of a second blackouts, then it turned to complete blackouts that lasted for almost a second, thing is some of those flickers weren't blackouts, I could actually see in some of them texture, like a youtube video I was playing but was hidden from another browser tab.

I'm pretty confident this is a software issue because a simple restart got rid of the flickering and it hasn't come back.

My new imac has the display problem, update from Apple didn't fix the problem.
What helps is changing the display to 1280x768, wait a few seconds and switch back to 2560x1440.
After the switch I'm flicker/blackout free for the rest of my session.
It returns after a few reboots.
Seems like the display looses the sync with the videocard.

Seems like the flickering problem has been associated with the C2D, i5, and i7 of the 27". I bought my iMac 27" C2D on December 17th. So far I haven't had any problems yet, but I haven't pushed this system to the max like many have on here. One thing to note, my imac was built and assembled in the States. From reading the posts in this thread, it seems many of the problems are associated with iMacs built in Shanghai, If I'm correct. Perhaps there was a lack of QC over there. Anyways, so far this 27" imac the best computer I've ever owned and its my first mac.

How have you determined that your mac was built and assembled in the US ?

If you look at the bottom of the stand, it says where it is assembled. Be careful as you know this 27" is very heavy. But my wireless mouse and keyboard is assembled in china, which isn't a bad thing, but you just never know.

Jon Abbott wrote:
I think I've figured out a way to reproduce the problem. If I play the movie "Stranger than Fiction" at or almost at full screen, the flickering starts roughly 1 hour into the movie. Once the flickering starts, it keeps flickering until I sleep or restart the iMac.

Now, that's interesting.
Jon, how are your screen saver, display sleep and system sleep settings currently configured?

Way back in the early days of this thread, someone claimed to be able to reproduce the problem based on their screen save/sleep settings.

Got my iMac last Monday. It's a week 52 machine from China. It was built with latest firmware and since day one has been showing all the syndromes already mentioned over here: flickering, black screen and or splitting.

I've tried zapping the PRAM and the AHT full test but the issues were still occurring. However since I reduced the display brightness to half (to help reduce heat) I have not noticed these issues (so far). I'm aware that it can take several days to reoccur but I though I should share this here and see if it would make any difference in machines still experiencing these issues.

David wrote:
What I would like to see is someone who experiences the flickers and also has a good Uninterruptible Power Supply (UPS) that has a display on the UPS (some have displays that show the voltage) put that display next to the iMac screen and video both the UPS voltage display and the iMac flickering at the same time. This might show whether there is some correlation in voltage in and the flickering.

Okay, here's one for you from earlier in this thread:
http://discussions.apple.com/thread.jspa?messageID=10801804#10801804

InVision wrote:
I have an inline UPS with a recorder. I was having trouble for about a week before I reset the computer. I checked the log of the UPS and during periods of my problems the power was conditioned without any fluctuations. Now other folks might be having some issues with power, but I am very sure I was not.

Schwa72 wrote:
sparkie-

a screenshot of the iStat widget running on my i7. As you can see my power supply temperature is at 46˚C. FWIW, the hottest thing in my computer always seems to be my hard drive.

Your fans are working hard. Mine show CPU 938, HD 1100, Optical 999 under normal use.

DeeJay SchmeeJay wrote:

Jon Abbott wrote:
I think I've figured out a way to reproduce the problem. If I play the movie "Stranger than Fiction" at or almost at full screen, the flickering starts roughly 1 hour into the movie. Once the flickering starts, it keeps flickering until I sleep or restart the iMac.

Now, that's interesting.
Jon, how are your screen saver, display sleep and system sleep settings currently configured?

Way back in the early days of this thread, someone claimed to be able to reproduce the problem based on their screen save/sleep settings.

My computer and display sleep settings are both on 15 minutes. I have the screen saver set to "Hyperspace" but it is set to never come on. Wireless is off. I also should note that I used HandBrake 0.9.4 to encode "Stranger Than Fiction" using the default encoding settings. I played the encoded version either using the full screen or fit to screen modes using Quicktime Player. The display brightness is set to two steps below maximum. I can't say for sure whether this will work for others, but it has worked twice in a row for me even after rebooting. That seems to be better than any other method I've tried for reproducing the problem. I'll play it again now and see if it works a third time.

Happy New Year everyone!

ive used handbrake about 10 times since i got mine and had no flickering as of yet

sparkie1984 wrote:
ive used handbrake about 10 times since i got mine and had no flickering as of yet

I haven't had flickering issues when using HandBrake. The flickering started when watching the HandBrake encoded version of "Stranger than Fiction", on two separate occasions.

Update: I was just able to reproduce flickering a third time using the method described in my previous post. This time around I played "Stranger than Fiction" using the Fit to Screen mode of Quicktime Player, and the flickering started 46 minutes in (earlier than usual). It may sound like a strange method for reproducing flickering, but it has worked every time I've tried it so far.