20" Cinema Display won't adjust brightness

Joined
Jan 10, 2010
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Location
North Wales
Your Mac's Specs
MBP 13" 2.26GHz
For no apparent reason the screen brightness keys on my keyboard and the buttons on the side of the monitor have just stopped working, what is even more confusing is even on the display pane of system preferences it doesn't give the option to adjust the brightness by means of a slider either, even though it does for my mbp's display.

All of these functions worked correctly until I tried to adjust the brightness today, I've restarted twice to no avail, and I am now completely baffled by this! Any help would be very much appreciated as the monitor is blinding me in my dark office!
 
Joined
Jun 3, 2010
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Did you ever find a solution? My 23" ACD has just started doing exactly the same thing!
 
Joined
May 18, 2008
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Location
Amberley, Canterbury, New Zealand
Your Mac's Specs
MacMini 14.3, 8.1 & 4.1, OS 13.5, 10.14, & 10.11 & 10.6; Macbook Pro 8.2, OS 10.12.
Some things I can suggest:
1. Boot from your Install disk, and run Disk Utility > First Aid.
2. Repair Permissions, preferably using OnyX Titanium Software suitable for your OS version.

Are any other SysPrefs 'unavailable' to you; and does the cinema display itself have a brightness control that you can use to override the Mac controls?
 
Joined
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I have repaired permissions, and gone through maintenance with Onyx. None of it is having an effect. The brightness button controls on the side of the monitor itself, along with the power button have stopped working. So I have no way of adjusting the brightness either from within system preferences, or on the monitor itself. The only way I can turn it off at the moment is to unplug it.
 
Joined
May 18, 2008
Messages
3,612
Reaction score
95
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Location
Amberley, Canterbury, New Zealand
Your Mac's Specs
MacMini 14.3, 8.1 & 4.1, OS 13.5, 10.14, & 10.11 & 10.6; Macbook Pro 8.2, OS 10.12.
It's likely then to be a hardware issue, something not right with the video component of the logic board. Which means doing as suggested in No 1 of my previous response. If repairs cannot be effected from the Install disk, then you could try Disk Warrior, but it's expensive.
 

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