Screen Dims For No Reason

[roma1953]

I purchased a 15” MacBook Pro back in December of 2008 (currently still running Snow Leopard) which is still performing well with no serious problems. However, I have noticed in recent months that at night when I am watching a movie or video if I turn off the lights in the room where I keep the computer the screen will dim slightly and the brightness indicator will decrease about two clicks. If I manually increase the brightness the screen remains a bit dim even if I turn the lights back on. I made sure in display preferences that the box that says “automatically adjust brightness as ambient light changes” is definitely UNCHECKED, disabled. Also, my MacBook Pro is always on electric power--not battery---when I am using it at home. If I turn on the lights and shut down the computer and then restart the screen brightness returns to normal. If I turn off the lights the screen dims again. I would appreciate any suggestions from the community here on how I can perhaps fix this minor but nevertheless annoying problem. Thanks in advance.

 

[jondunford]

I purchased a 15” MacBook Pro back in December of 2008 (currently still running Snow Leopard) which is still performing well with no serious problems. However, I have noticed in recent months that at night when I am watching a movie or video if I turn off the lights in the room where I keep the computer the screen will dim slightly and the brightness indicator will decrease about two clicks. If I manually increase the brightness the screen remains a bit dim even if I turn the lights back on. I made sure in display preferences that the box that says “automatically adjust brightness as ambient light changes” is definitely UNCHECKED, disabled. Also, my MacBook Pro is always on electric power--not battery---when I am using it at home. If I turn on the lights and shut down the computer and then restart the screen brightness returns to normal. If I turn off the lights the screen dims again. I would appreciate any suggestions from the community here on how I can perhaps fix this minor but nevertheless annoying problem. Thanks in advance.

is the battery healthy?

theres another setting that dims the display when it comes off charge and if your battery is unhealthy and intermittently charges it might be playing with this

 

[Starfyre]

Might have something to do with the inverter.

 

[Astroboy907]

Do you have dimming checked in the energy preferences? I know that most macs automatically dim the screen after a certain time of inactivity.

 

[roma1953]

Thanks for the advice but----

Thanks for the suggestion. However, dimming is not checked in energy preferences. My screen dims only when I turn off the lights and the room is dark. Otherwise screen brightness is at the max level which is where I normally keep it when plugged in. So it also cannot be a battery problem as another poster suggested or the inverter. I assume this issue must have something to do with the fact that even though the adjust brightness to ambient light option is disabled---not checked---for some reason my MacBook Pro is overriding that preference when the room is dark. Kind of strange.