MacBooks forum


Keyboard & screen back lights pulsate

by arnthal / May 23, 2013 4:13 AM PDT

I have a MacBook Pro 15" early 2008 running !0.5.8.
Last night the keyboard illumination began pulsating bright-dim-bright-dim. At the same time the screen display began pulsating, too, sometimes alternating with the keyboard, sometimes in unison and sometimes unconnected, it seemed. Trying to control the keyboard light with F5 & F6 keys only showed me the usual semi-circular display blacked out with a little prohibition symbol underneath (circle with a diagonal line in its center). I tried the following remedies without any result.

reset PRAM
repaired permissions
ran Preferential Treatment for system preferences
reset SMC

Then I unchecked the automatic dimming control for both keyboard & screen. Now the keyboard continues to pulsate but at avery dim level. The F5 & F6 controls remain as before. The screen however does not pulsate. That is where I am at this point.

Has anyone had experience with this? I suspect I may have to reinstall the operating system as there are some other irregularities from time to tim,e.

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All Answers

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As a test.
by R. Proffitt Forum moderator / May 24, 2013 5:05 AM PDT

Boot the OS DVD and see if the issue continues. We don't need to do anything but boot the OS DVD. We are not looking at reinstall or answering ANY question to that boot. We only want to boot the OS DVD and see if the pulsing continues.

If it does then your laptop needs repairs.

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by arnthal / May 24, 2013 5:42 PM PDT
In reply to: As a test.

I rebooted from the installation disk, but it went straight to installation and did not give me a desktop or other functions to work with. Hence, there was no response to the keyboard back light controls, not even the blacked out semi circle. Instead I rebooted into a partition created by my TechTool Pro program and here I was able to get a response. It was the same as with the installed OS. That is, displaying the blacked-out semi circle with no response to the back light controls. I will take the computer to an Apple Store at the first opportunity for whatever repairs are necessary. Thanks for your help, Bob.

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Glad you tried that. But get an estimate.
by R. Proffitt Forum moderator / May 25, 2013 2:00 AM PDT
In reply to: Results
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