Strange noise when the screen is on (after have plugged an external Cinema Display)

[philsurmac]

Hi there,
Since I plugged my Cinema Display (20" alu) to my MacBook Air... I hear a strange sound inside the computer.
It comes as I guess from the graphic card, or the power, because when I turn off the screen (by putting down the brightness at its maximum), this time there is no sound anymore. When I turn it on, the sound restarts (by being high when the brightness is down, and down when the brightness is at its maximum).
Is anybody has any idea please ?
Thanks

 

[Scottsdale]

Hi there,
Since I plugged my Cinema Display (20" alu) to my MacBook Air... I hear a strange sound inside the computer.
It comes as I guess from the graphic card, or the power, because when I turn off the screen (by putting down the brightness at its maximum), this time there is no sound anymore. When I turn it on, the sound restarts (by being high when the brightness is down, and down when the brightness is at its maximum).
Is anybody has any idea please ?
Thanks

Do you have an original MBA? Or are you using MDP to DVI with a v 2,1 MBA?

 

[philsurmac]

I have the MacBook Air Rev A yes, the first one (mine was produced in july 2008 to be exact )