How do i adjust brightness for 24 inch LED Cinema Display?

Discussion in 'Mac Accessories' started by nawoo, Mar 4, 2009.

  1. nawoo macrumors regular

    Feb 3, 2008
    Alright i turned down the brightness last night to half. Unplugged my macbook pro and took it somewhere else.

    Plugged it back in the morning, the LED powers up at half brightness. But Lo and Behold, i can't adjust brightness anymore.
    The f1 and f2 keys don't work!! All other keys on my apple wireless keyboard work.

    I go into Displays under System preferences. The only option to adjust the brightness shows as Color LCD, which is for my MBP.

    Under LED Cinema Display, There is no slider to adjust brightness!! The Apple LED cinema display guide says to either press the f1 & f2 keys, or go into System Preferences and use the slider. But WTF, where the hell is the slider.

    I've already tried using different arrangements. I've always set my LED display as the primary display, and have always been able to adjust my brightness.

    WHy can't i do anything now??? I'm sitting here with a very dim 24 inch monitor
  2. alphaod macrumors Core


    Feb 9, 2008
    Have you tried restarting your computer with the display plugged in?
  3. thecreativ1 macrumors member

    Jan 19, 2007
    MD, USA
    Bump. This is a problem for a lot of people. Apple's support discussions page has lots of threads on this, with no fix that I've seen yet. It seems to have something to do with how the external displays interact with the Intel GMA950 graphics. I have this same "no brightness slider" bug with a Mac Mini C2D and a 20" Cinema Display.
  4. superscientific macrumors regular

    Mar 18, 2003
    Spring Hill, TN
    I know this sounds crazy but is your display USB plugged into the computer? Without that it will not be able to control your display settings. I did the same thing with my Mac Pro at first and was getting so frustrated. But then I realized that my USB from the display was not plugged in. I plugged it in and BAM! There came my display slider and the keys for brightness worked again. If it is plugged in then sorry, I just thought I would post just incase people were not plugging the USB in. This is on the new 24" LED Cinema Display.
  5. nawoo thread starter macrumors regular

    Feb 3, 2008
    yup, the USB needs to be plugged in before the slider can show up.
    Works everytime now
  6. bridgeandtunnel macrumors newbie

    May 17, 2010

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