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

25047 Views 50 Replies Latest reply: Dec 13, 2013 5:35 PM by hoppah RSS
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Christian Fries Level 1 Level 1 (60 points)
Currently Being Moderated
Dec 2, 2010 12:29 AM
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)
  • pvblivs Level 1 Level 1 (0 points)
    I can confirm that this happens "below six bars".

    One workaround to his issue is to not use the automatic brightness adaption and let the display on six or bars. This is quite bright when it is dark but ok and not too dark on daylight.
    2009 15" MacBook Pro, Mac OS X (10.6.5), Cinema Display 27"
  • IslandOwl Level 1 Level 1 (0 points)
    It appears I am getting the flickering when the screen is warmed up. However it started happening right after I did two things: 1. I watched a TED Talk video at full screen. I don't know if that somehow set it off - can't imagine why it would. 2. I moved the top toolbar from my laptop screen over to the LED display. I did these two one right after the other so I am not sure what set off the flickering.

    Now, after I have had the screen unplugged for quite a while so it cooled down, it seems to be working okay again. Still, as that this display is all of 2 days old this is very concerning.
    Macbook Pro, Mac OS X (10.6.5), 27" LED Cinema Display
  • IslandOwl Level 1 Level 1 (0 points)
    Okay, I was able to reproduce exactly the same thing as Christian. Having the power cable from the display hooked into my 15.4" Macbook Pro causes the LED screen to flicker. I did not check the amount of bars but since this is an intermittent problem it is either caused by the charging of the MBP or, I think I am seeing that this problem only occurs once the display is warmed up - has been on for a while. I keep my MBP plugged in when at my desk so the battery has not been below full charge, yet the flickering still occurs. If I have the MBP hooked up to its own power supply it is not a problem.

    Unfortunately, the odor problem continues!!
    Macbook Pro, Mac OS X (10.6.5), 27'' LED Cinema Display
  • Heeepa Calculating status...
    Hey guys,
    same problem over here with my brand new MacBook Air 13" + 27" Cinema-Display.
    The flickering happens everytime I connect my MBA to the Display with the MBA closed (wake-up via Bluetooth). If the MBA is open and I use the synchronize-function (which I think is terrible) or the extended-display there is no flickering at all.

    Edit: Same thing, under 6 Bars flickering, >= 6 Bars no flickering!

    Cheers from Germany

    Message was edited by: Heeepa

    Message was edited by: Heeepa
    MacBook Air, Mac OS X (10.6.5), Apple :)
  • kolner Calculating status...
    Same problem here
    When MBP 13" is connected with display charger and low lightness.
    When I unplug MBP, flicker goes away.
    Very annoying for a 1000€ screen.
    Would really want a solution or I'll have to give it back.
    imac aluminium, Mac OS X (10.5.5), 2.0ghz, 4gb ram
  • IslandOwl Level 1 Level 1 (0 points)
    Hey everyone, Give a look on your sound profile (System Preferences/Sound) and make sure that LED Cinema - Display Port is listed. My display has had multiple problems, of which the flickering is only one, and this final problem of the sound not working led me (and a Senior Apple Tech Support guy) to discover the missing option. He said that is a big problem when we were unable to get it to work. So, I am picking up a new display on Monday. Sigh. (The sigh is because it is not a small deal since I have to rent a Zipcar to do this exchange.) The store is going to check the display out to make sure it is working so hopefully round 2 will go without a hitch. I love the display!!!
    Macbook Pro, Mac OS X (10.6.5)
  • IslandOwl Level 1 Level 1 (0 points)
    Kolner, unless you hate the display for other reasons consider just using two power supplies. There are enough of us documenting the problem that Apple will likely take action on it - as long as it is something that can be fixed with firmware. If it is a hardware issue - that is going to be a whole different story. But since I don't plan to carry a 27" screen around in my backpack I just don't see the issue in having to use a separate power supply.
    Macbook Pro, Mac OS X (10.6.5)
  • Martin Jort Calculating status...
    Same problem here! I bought two brand new 27 inch Cinema Displays, one for work and one for my home office. Both showed the problem. I returned both, go replacement displays and both show the same problem. I am using them with a 13 inch MacBook Air late 2010. I use them with the MacBook's display lid closed and powered by the Cinema Display. The problem only occurs when the display brightness is at 1 to 5 bars. From 6 bars on everything is fine. I also noticed that the flickering is stronger when I USE the computer, i.e. dragging around windows, typing, etc. When I just look at the screen, the flickering occurs more sporadically. The flickering looks like a short switching off of the display light (a few milliseconds).

    I just tried the hint suggested in this thread and indeed, when I open the lid and have the MacBook running on batteries (not powered by the Cinema Display), the flickering is gone! So it really seems to be dependent on that.

    Please fix it, Apple! This is not acceptable for a premium-quality display! We have already done a good job narrowing down the conditions under which the problem occurs. You should easily be able to reproduce the issue like this:

    - use a MacBook (e.g. new MacBook Air) and turn it on
    - plug in all three cables provided by the 27" Cinema Display (power, DisplayPort, USB)
    - close the lid of the MacBook and re-awake it with an external keyboard so the Cinema Display will be the only display in use
    - wait a few hours for the Cinema Display to become warm (not sure if this is a necessary condition but it could be)
    - then, use the computer under low-light conditions and ensure the brightness is at 5 bars or less

    --> You will see the problem.

    By the way, the recent Cinema Display firmware update (to address the audio issue) did NOT solve this problem.
    MB Air, Mac OS X (10.6.5)
  • Martin Jort Level 1 Level 1 (0 points)
    Oh, and regarding what IslandOwl wrote, I do not have any issues with that. The LED Cinema Display is listed with two entries, USB and DisplayPort under System Settings / Sound and sound has always worked fine for me.
    MB Air, Mac OS X (10.6.5)
  • hausersn Calculating status...

    I have the same problem, too. The 24 inch cinema display I owned before didn't flicker when it was dimmed down.

    I hope Apple can fix this problem soon.


    MacBook Pro 13" Cinema Display 27", Mac OS X (10.6.5)
  • mhagstroem Calculating status...
    Yesterday I bought an ACD 27” (USD1500, yay for living in Sweden!) to be used with my MBP 13”.

    Running Aperture 3 I immediately noticed that something wasn’t right. Moving the mouse over specific parts of the screen made the light go nuts!

    While trying to figure out what was going on I also noted that this only happens when brightness is set below 6.

    Wanna see something funny? Pull out your widget clock and have something white in the background. Now your ****** expensive ACD flickers in tune to the second hand! Wow.

    So what to do – return it to Apple or hope for a software update that takes care of this problem?
    MacBook Pro 13" / ACD 27", Mac OS X (10.6.5)
  • IslandOwl Level 1 Level 1 (0 points)
    Be sure your firmware is up to date. The latest upgrade was released December 15th. Though it does not claim to address the flickering issue, I have had almost no flickering issue at all since I updated the firmware.

    2009 Macbook Pro 15,4"
    27" LED display screen
    OS 10.6.5
    Macbook Pro, Mac OS X (10.6.5)
  • mhagstroem Level 1 Level 1 (0 points)
    Yup, did the update as soon as hooked up the ACD. Worth to mention is that I discovered the flickering thing after the update.

    Btw, im writing this in Word and every time I press a button it flickers haha!
    MacBook Pro 13" / ACD 27", Mac OS X (10.6.5)
  • DieLaughing Calculating status...
    I have worked as a tester at Apple and I can reproduce this and I am just disgusted at how bad this problem is. I'm taking every last monitor in my entire company back to the store for a full refund. They aren't going to fix this. At least I know better than to wait.
    MBA 2010, Mac OS X (10.6.6)
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