Anyone else having this problem? The screen flickers quite a bit at the lowest 4 or 5 brightness levels, or when the screen dims after idle time.
I can't believe I have to haul this thing back to the store....
iMac, Mac OS X (10.6.7)
My 2011 27" iMac Core i5 (3.1 Ghz) is doing the same thing. I've turned off the screen dimming and ambient sensor to check - no change. I do NOT want to haul it in, either. I just got it this afternoon. Any thoughts, anyone?
I also turned off the automatic ambient light adjust.
This is different from the flicker on the previous generation iMacs. Its almost like the old 60hz interlaced CRT displays -- you can see it more in your peripheral vision. It occurs constantly, though the magnitude of it seems to fluctuate.
It occurs even on the gray and blue start-up screens so I don't think its an OS issue.
Resetting the PRAM/NVRAM (hold command-option-P-R at boot) didn't help.
Same here on the 21.5" entry model 😕
There is an iMac EFI Update and a update of Mac OS X 10.6.7 for the iMac available that you should probably try before anything else.
Best of luck.
Message was edited by: laundry bleach
The updates didn't help.
I've noticed in a brightly lit room I can't really see it.
I found this in a Wikipedia article. This is my first LED backlit screen so it might be an inherent problem. Ugh.
http://en.wikipedia.org/wiki/LED_backlight
Flicker due to backlight dimming
LED backlights are often dimmed by applying pulse-width modulation to the supply current, switching the backlight off and on again like a fast strobe light. If the frequency of the pulse-width modulation is too low and or the user is very sensitive to flicker, this may cause discomfort and eye-strain, similar to the flicker of CRT displays.[5] This can be tested by a user simply by waving a hand or object in front of the screen. If the object appears to have sharply-defined edges as it moves, the backlight is strobing on and off at a fairly low frequency. If the object appears blurry, the display either has a continuously-illuminated backlight or it is operating at a frequency that is too high for the brain to perceive. The flicker can be reduced or eliminated by setting the display to full brightness, though this has a negative impact on image quality and battery life due to increased power consumption.
I seem to be having the same problem. Brand new iMac 2011 Core i7 27".
I have the same problem screen flickering and never come up to full brightness, when is brightness full in 1 minutes automatically flicker and brightness down, it's like not support full brightness or something...
And when i change the brightness flicker again. It's looking hardware problem for me but i'm not sure because 2009 imac models had worsed flickering issues and Apple send update for this issues, maybe if we can wait they send another update for this thing...
Apple did have a flickering problem with a previous version of iMac and there were people, then, who said: "Wait for an update" or "Wait for a software remedy." The only remedy is to return it. Like last time, you may get another screen that flickers. Then, the only remedy is to get your money back. Then, no one came charging on a white horse from Apple headquarters with a solution and no one is going to come now. The choice is yours.
Yes you're right but i'm living istanbul/Turkey and when i take back my machine for repairing service they really don't know what is the problem and i had really hard time to explain vs.
And repairing not working well here they change every part till problem going away, and the parts it's coming us or china and this period took at least one month for each part (logic, screen, RAM vs.)
Thanks for reply...
I have the same problem (in Switzerland). Just bought imac 27" i5, when dimming 2/3/4 bars the illumination of the panel vibrates like a candle..... at 1 bar is ok, at 5 or more is ok too.
Mine is iMac 27" i7 2.93 Ghz model.
And today eventually half of screen goes dark shadow. It's like my left eye slightly seeing.
I really don't understand now i have to go service and i have to wait at least one or two months.
And it's my second machine has the same problem first one is MBP.
All of Apple LED screens are really really bad quality, bad bad quality, everytime i have to be change mac parts why i have to do this why is not working well i paid 1500$ for it. Is it not enough?
I really don't understand.
i'm using mac at least 20 years. But i start the thinking about the change the system.
I'm not sure about Apple anymore.
Sorry for my deficient english...
Same issue here... 27" imac mid 2011, 3.4GHz i7, 2GB Graphicmemory... flickering at low brightness. 😟 Anybody fixed this Issue by returning his Device or is this a common Issue at all new imacs and we have to wait for a Fix from Apple?
Hi! I brought my imac back to the shop, explained the problem and changed with another imac 27 i5.
The new one is perfect! No flickering, no "candle effect".
I think it was an hardware problem.
IMO don't lose your time waiting for a solution that maybe will never come... bring it back, take a new one and enjoy!
It's a very nice computer!
Hey Abe75
Well i've a Build to Order Configuration. 😟 I don't think that the Applestore can replace my Device directly in the Store and i've to wait a long time for my replacement.
Greets Primalair
I understand.... but I think is better to stay a couple of weeks without computer and after to be 100% happy.
This flickering problem is very annoying when using computer at night (big headache) .... and a quite expensive computer in 2011 can't have a screen like the worst crt monitors in 1980.
I hope that Apple will improve the quality check on this product. A faulty unit could always happen, but when there are many, is important to react quickly and inform the customers.
I hope that your computer will be back soon from store! The 27" screen is gorgeous!
bye
albe75
2011 core i7 27" screen flicker at low brightness
