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Level 1

11 points

27" Cinema Display - No Brightness Control

I have read over all the threads here and the internet. I have an iMac (black back) that my 27" Cinema display is connected to. USB and Displayport are both connected. Everything appears just fine. However, I cannot adjust the brightness on the Cinema display. I have tried everything. I even hooked it up to my Macbook Pro early 2011 model. Still the same issue. There is no brightness slider. The slider only appears for the native display only. Never the Cinema display. What am I missing?

Running Lion on both machines.

Posted on Dec 8, 2011 3:21 PM

21 replies

Aug 28, 2012 10:24 PM in response to thomasinfromca

I got it to work. Not sure how. Thank you. Brightness control is back.

J Rye

Level 1

4 points

Oct 4, 2012 2:37 AM in response to thomasinfromca

I had the same problem: "Reset EDID" was inactive/ greyed out.
However i found out that my cinema display usb-cable was not plugged in to my macbook pro. Once i did this, the "reset EDID" button became clickable!

mainecat

Level 1

8 points

May 17, 2013 8:27 PM in response to SpurtSpanker

Thank you for this tip. I have been suffering in darkness, now I can see! This information should be easier to find.

jmarshal

Level 1

4 points

May 31, 2013 7:43 PM in response to mainecat

The button was greyed out for me as well even with the USB cable plugged in. I disconnected and reconnected the USB cable and it worked.

Jun 8, 2013 7:48 PM in response to SpurtSpanker

Thank you thank you!

Back in Dec 2011 I had a 27" Cinema Display repaired and this happened. Took it back to the store and they assumed the board was bad. Gave me a new display.

Fast forward to this past week Jun 2013....had the display in to have the LCD replaced because of smudge like marks. Sure enough I get home and same issue....no brightness controls!

I searched and found this thread. Downloaded the tool and voila! Brightness controls back.

Surprised the geniuses don't know about this!

-Kevin

lenbom

Level 1

0 points

Jan 19, 2016 4:13 PM in response to SpurtSpanker

After running the EDID reset tool, my display still did not show brightness control. I found out that you may need to unplug the display for more than 2 min. to get a proper EDID reset. The 10 sec. given in the instructions was not enough in my case. Hope this helps somebody.

27" Cinema Display - No Brightness Control