dlisanto

Q: 27" LED Cinema Display, no brightness control

I have a 27" LED Cinema Display that has the Mini DisplayPort cable and I am plugging into a MacbookPro 15" with a thunderbolt port. When I go into System Preferences there is no brightness control or ability to turn off automatic adjustment for the LED display, just the computer. I have the usb port plugged in as well. I have seen previous updates to fix this for earlier versions (10.6) but that didn't work on my OS X 10.8.2. Is there anything to remedy this? The automatic adjustment of brightness is very distracting and I would like to have control of the brightness of my monitor.

MacBook Pro, OS X Mountain Lion (10.8.2)

Posted on Feb 12, 2013 8:23 AM

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Q: 27" LED Cinema Display, no brightness control

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  • by Larry Willis,

    Larry Willis Larry Willis Mar 2, 2016 1:10 PM in response to dlisanto
    Level 1 (5 points)
    Mar 2, 2016 1:10 PM in response to dlisanto

    Still works!



    Took me several hours to figure out so I'm adding a couple of follow up notes that may be helpful...

     

    1. Once you download the http://download.info.apple.com/Apple_Hardware_Test/EDID_Reset_Tool.dmg double click the file to mount the EDID_Reset_Tool.dmg install drive on your desktop. Open the drive then double click LED Cinema Display (27-inch) EDID Reset Tool v1.3 installation icon

     

    If you get the warning that the file cannot be opened, hold down on the CTRL key and double click the LED Cinema Display (27-inch) EDID Reset Tool v1.3 installation icon if you get the warning that the file cannot be opened.

     

    2.  Be sure unplug monitor power from source (rebooting the computer didn't reset the monitor for me)

     

    Note:  If you are using a dual display the brightness keys on the keyboard will only control one of monitors brightness, you'll need to go into System Preferences to manually adjust the brightness for the other monitor.  Additionally if you are running a dual display setup disconnect the monitor that is functioning correctly.

  • by AED1971,

    AED1971 AED1971 Mar 9, 2016 6:39 PM in response to TOAO
    Level 1 (0 points)
    Mar 9, 2016 6:39 PM in response to TOAO

    Wow, after a few years of not being able to adjust brightness all I had to do was plug in the USB before the mini display!!! Thank you!

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