23" Cinema HD Display, model A1082 | Lost brightness control

Discussion in 'OS X Mavericks (10.9)' started by androidarmy, Dec 1, 2015.

  1. androidarmy macrumors newbie


    Feb 8, 2012
    San Pedro, Ca
    This monitor is attached to a MacBook Pro, 13-inch, Mid 2012, 2.5 GHz Intel Core i5, running OS X 10.9.3, via a Thunderbolt to DVI Adapter. After a power failure, the monitor has been exhibiting the following symptoms:

    1) Screen does not go all the way black during sleep or when not connected to the laptop
    2) Power button on the right side does not function
    3) Brightness controls on the right side do not function
    4) There is no brightness control on the "Displays" preference pane
    5) Power light is currently not illuminated*
    *during troubleshooting attempts, however (e.g., between restarts), the power light has illuminated, flashed the "short-short-short" signal which is addressed in this article: Apple LCD displays: Power light flashes - Apple Support

    I have tried the following to alleviate the situation:

    1) simple restart
    2) Reset NVRAM
    3) Reset SMC
    4) Disconnected and reconnected the Thunderbolt to DVI Adapter
    5) Disconnected and reconnected the Power Supply (allowed to rest overnight as well)​

    I realize at some point, I will need to eliminate the variables of the Adapter as well as the Power Supply by trying replacements. I have ordered the former. However, since the latter is at least $50-$100 to replace, I want to exhaust all other possibilities before securing a new supply.

    Thanks in advance for any help or suggestions you may have!
  2. hamis92 macrumors 6502

    Apr 4, 2007
    If the display doesn't go completely dark when disconnected from the computer, it looks like the fault is within the display itself, and trying a different DVI adapter will do nothing to fix it. I suspect that some of the components that talk to the computer over USB (touch buttons, brightness control) and manage power (backlight) were damaged in the power failure.

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