screen goes black when i increase brightness

Try resetting the PRAM and SMC.

SMC RESET

• Shut down the computer.
• Unplug the computer's power cord and all peripherals.
• Press and hold the power button for 5 seconds.
• Release the power button.
• Attach the computers power cable.
• Press the power button to turn on the computer.

PRAM RESET

• Shut down the computer.
• Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
• Turn on the computer.
• Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
• Hold the keys down until the computer restarts and you hear the startup sound for the second time.
• Release the keys.

nicholasfromconfolens wrote:

Tried it..alas still the same! Iam not sure if it is software related...it seems that it never happened in leopard...only a couple of weeks after lion. notch 3 is ok for most things.. its only occasionally I would like to increase it.

C'est la vie.

Nick.

I can say that because I live in France.

OK, try restarting when you hear the start up tone hold down the Option key and choose Recovery Disk. Then open Disk Utility, select the internal HD on the left pane, the Repair Disk Permissions, do this at least 2x. While you're in DU run Repair Disk again 2x. Then exit Disk Utility and restart the computer in Safe Mode, this will clear some caches. Then restart normally and test. If you continue to have the same problem book an appointment with a Genius at your local Apple Store and take it in. It's possible your install of Lion didn't go well and it may need to be reinstalled. If you want to do this yourself you can, you will see the option when you restart from the Recovery Disk.

Nick,

That's great glad it's OK, sometimes doing these resets takes 2-3 attemps before they "take."

Best,

Roger

I just wanted to say that for the past few weeks I had been dealing with SAME "Black Screen" issue and could not take my brightness level over 5 bars on my 27' imac. Each time I tried to increase my brightness my screen would immediately go BLACK... I thought maybe it was getting too hot and why it was shutting down, but quickly ruled that one out.. So I was about to carry my computer to the Apple Store (1.5hrs away) but then found this thread, THANK GOD, because following the PRAM reset instructions did the trick and fixed/resolved the issue.. FULL brightness now and no more going BLACK, so THANK YOU Roger, for supplying those HELPFUL instructions, your the man!! 🙂