Hi, all.

I have a 2008 MacBook Pro 2.4 GHz with 2GB's of RAM running 10.5.8 & recently the display keeps dimming if I stop typing even momentarily.

I've checked Sys Prefs & all's o.k. there so I'm baffled as to why.

Any help appreciated,

Cheers, Phil...

Look at the Keyboard & Mouse preference pane and go to Keyboard Shortcuts. See if the shortcut for dimming the display is checked (you can deactivate it if necessary). You may be accidentally pressing it.

Hi, Jon.

Thanks for that. I've disabled that option following your advice (incidentally after doing it the brightness went down in the Display Prefs). I've disabled all third-party Screensavers & that's made no difference so I guess I'll have to dig out Apple's Hardware Test disk (if I have one) & see if that comes up with anything.

Cheers, Phil...

Just a thought: Is there anything in the Energy Saver preference pane that might be dimming the display? I ask because a friend has an iMac that automatically dims the display after a preset period of inactivity. My system doesn't have that option so I can't experiment.

There is an option to automatically dim display before sleep which I use when on battery power but not when I'm using the power supply as I am at present.

The other odd anomaly is that it only happens in all applications. If I hide everything, it doesn't occur on the Desktop. It also kind of pulses in & out albeit very subtly.

I have extended Apple Care so it may need to go back before that expires in July this year (I ran TechTool Deluxe on the Video RAM & it gave it a clean bill of health)...

Before taking AppleCare of your Mac, it may be helpful (and easier) to look into another possibility. Your problem may be a settings issue, and restricted to a particular user. If so, things should be fine when tested under a new or known clean user account. In that case, the problem likely lies in a corrupted prefs file or cache. Given the nature of your problem, the relevant Display and Energy Saver prefs are then first in line for temporary removal to test their involvement.

Just a thought but, when you assigned your settings in the Energy Saver panel, did you "Click the lock to make changes"? I only ask because I made that mistake myself.

I was experiencing dimming every couple of minutes. When I checked my settings I found I had set Computer and Display Sleep to 10 minutes and checked off three options, including "Automatically reduce brightness before computer goes to sleep".

However, I hadn't clicked the lock, and doing so solved the problem.

ryck

Hi, Ryck.

On my system (10.5.8) it automatically saves your changes & locks itself when you quit Sys Prefs.

I was just about to consider zapping the PRAM when the problem disappeared as mysteriously as it arrived. Very odd...

I looked at the Console logs & there was nothing suspicious so hopefully it's sorted itself.

Cheers, Phil...

Hi, alternaut.

I did log in to the Guest Account & it was the same deal. If it returns (see previous post) I'll take a look at the relevant prefs/cache files.

Cheers, Phil...

sounds like a corrupt energysaver'ish plist?

Admittedly this is a shot in the dark, but how long has it been since you calibrated the battery? The screen may be dimming because the battery is sending erroneous data to the MacBook Pro.