Just bought a new IMac and put my old second and third monitors to it. All is well but I want to adjust the brightness of the seond and third monitors and I can't seem to do it. The controls only seem to work on the IMac display. Thanks, Ed.
iMac, OS X Mavericks (10.9), Other 2 monitors are old Cinema HD
It's been quite some time but I've been looking for answer to this problem and it is: CTRL+brightness keys to modify the secondary display. Not sure about third one.
It's been quite some time but I've been looking for answer to this problem and it is: CTRL+brightness keys to modify the secondary display. Not sure about third one.
Hey zoeycs,
I found the following information on adjusting the brightness level on Cinema Displays:
This software updates the System Preferences pane where you can change Ambient Light Sensor settings. Enable the option "Automatically adjust brightness as ambient light changes" to turn the ambient light sensor on and off. Use the slider to adjust the brightness level.
Note: You must have the cinema display's USB cable connected directly to your Mac to access this functionality.
via: About the 27-inch LED Cinema Display Software Update 1.0
I would try to connect the display's USB cable to your Mac and then try adjusting the brightness to see if that works.
Welcome to Apple Support Communities!
Sincerely,
Delgadoh
I have the USB connected and I open the Display window and enable the Automatically Adjust brightness, but the slider only affects the iMac window, makes no difference to the other windows. Both the other windows get their own Displiay window in them, but they do not have any options for the brightness or a slide bar. They are effectively useless. Thanks for trying, Ed.
This worked perfect. Just had to close and reopen System Preferences and it took.
Been working with a dim third monitor for over a year - thanks!
THANK YOU! OMG was driving me nuts!
Have a great one!
adjust brightness on second and third monitor on iMac setup
