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27'' LED Cinema Display flickers when powering MBP and dimmed down

The 27'' LED Cinema Display flickers (backlight flickers) in the following situation:

* The display powers an MacBook Pro (e.g. later 2010).
* The MacBook Pro is fully charged (i.e. power is not used for charging).
* The MacBook Pro performs some GPU intense task (moving the mouse over the dock with magnification enabled).
* The brightness of the display is dimmed down to one of the lower settings (one or two "bars").

The problem disappears if the MBP is powered by an independent charger.

We reproduced the problem with two different MBPs (13'' and 15'') and two different displays.

MacBook Pro 13 (MBP5,5),MacBook Pro 15 2.4 (MacBookPro3,1), Mac min CD2, PowerMac Cube, PowerBook G4, Mac OS X (10.6.5)

Posted on Dec 2, 2010 12:29 AM

Reply
55 replies

Feb 7, 2011 5:38 AM in response to Christian Fries

Just adding that I'm in the same boat as the rest of you. I just received a refurbished 27" LED Cinema Display which is connected to a 13" MacBook Pro, which I'm using in "closed" mode. I had noticed the flickering and lower brightness settings and so decided to check out the support forums.

NOT powering the MacBook Pro from the Cinema Display resolves the issue (as others have noted) although that tends to mitigate part of the benefits of using Apple's Cinema Display over less expensive competitors.

Hopefully someone at Apple is looking at the forums since their isn't a an option for "displays" at www.apple.com/feedback/ . This issue needs to be resolved so the product can be used as described.

Apr 8, 2011 5:12 AM in response to Christian Fries

I can replicate this problem consistently with my 27" LED Cinema Display purchased in January 2011.

When the 27" LED Cinema Display is powering my Macbook Air 11" via the built-in magsafe charger, AND the brightness control is below 50%, the display flickers.

Removing the magsafe charger stops the flicker.

Plugging the magsafe charger back in, the flicker returns.

Turning brightness above 50% brightness, the flicker disappears.

The question is - has anyone got a 27" LED Cinema Display that doesn't exhibit this fault?

Jun 15, 2011 4:07 PM in response to Christian Fries

I just got a new 27" LED Display...


Actually, I got FOUR! :/


First one had multiple sub pixels. The replacement had bunch of dust under the screen and dead pixels in the lower left. I gave up and decided to go to a local Micro Center, where one of them had blue sub pixels everywhere on the right side of the screen, roughly two inches off the bezel. Finally, the fourth one was perfect; however, I've noticed the flickering too!


I'm using it with the 2.8 Quad Mac Pro and it flickers until setting 6. At setting 7, it goes back to normal. I believe only one of all four didn't really flicker. No help but to deal with it I'm assuming 😟


I'm just very disappointed with Apple's quality control. If I wanted a monitor with this many faults, I would've saved myself money and gotten a $200 piece of junk, not a $1000 display!

27'' LED Cinema Display flickers when powering MBP and dimmed down

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