Dual Displays have different brightness

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Level 1

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Dual Displays have different brightness

Hi All-

I'm at the end of my rope with this situation.... two apple cinema displays which won't match brightness. When a single display is plugged in (either display) it looks to be normal in brightness, contrast and color. As soon as a second display is plugged in the second display dims. I've replaced the graphics card, bought a new display, changed slots etc. I notice that this differential is present from the start... the blue screens during boot looks clearly mis-matched.

Can anyone help shed a bit of light on this situation? I'm a video editor and am using my second display for color correction.

Here are my exact details:

Power Mac Quad core running 10.6.8

NVIDIA GeForce 8800 GT (this is the second of identical cards I've tried.)

Displays:

#1 Cinema HD:

Resolution: 1920 x 1200

Pixel Depth: 32-Bit Color (ARGB8888)

Display Serial Number: 2A******UG0

Main Display: Yes

Mirror: Off

Online: Yes

Rotation: Supported

#2 Cinema:

Resolution: 1680 x 1050

Pixel Depth: 32-Bit Color (ARGB8888)

Display Serial Number: 2A3456Z7PKL

Mirror: Off

Online: Yes

Rotation: Supported

Thanks!

Dan

MacBook Pro, Mac OS X (10.6.8)

Posted on Sep 28, 2011 12:56 PM

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Answer 1

ILoveSax

Level 1

0 points

Sep 29, 2011 9:09 AM in response to goodeyevideo

There is a bug in the Apple Cinema Display or the iMac that controls it.

THE CINEMA LED DISPLAY BRIGHTNESS CONTROL SLIDER IS MISSING.

1. The apple support did not know anything about the problem.

2. It happens over and over on both of my iMac/Cinema systems.

3. I fix it, and then it happens again.

This time, after numerous unsuccessful trys to get the brightness slider to work on the Cinema Led display, I tried holding both keys down at the same time:

"Command" +"F1", and low and behold, up popped my Display Preferences WITH THE BRIGHTNESS CONTROL/SLIDER ENABLED!

*************APPLE SUPPORT, PLEASE TAKE NOTE AND GET THIS PROBLEM FIXED PRONTO. IT IS VERY FRUSTRATING TO HAVE TO FIX THE SAME PROBLEM OVER AND OVER!*******************

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Answer 2

Rohrbach

Level 1

4 points

Nov 1, 2011 8:47 AM in response to ILoveSax

Thank you - I had the same problem, and this let me change the brightness of the second display, finally... still, it's clearly a bug in the system somwhere, so it would be nice if Apple could fix it.

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Answer 3

goodeyevideo Author

Level 1

0 points

Nov 1, 2011 9:55 AM in response to ILoveSax

In what window/program did you hold down F1 + Command?

Thanks!

D

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Answer 4

Nov 25, 2011 4:54 AM in response to goodeyevideo

Hi,

I came upon this thread because I googled the serial # of my Cinema Display that i found in System Profiler

2A******PKL

mine is a 23" display but you have 1680x1050 listed as your resolution

just want to figure out how we could have the same serial #

also the serial # on the removable plastic footer of my display does NOT match this number, not even close, and i'm trying to get to the bottom of this. i bought it on ebay a week ago.

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