2009 iMac 27" fluttering display brightness

I assume this is a 2009 model having purchased it in February 2010. I am mostly confident this is an LED display. I am running the latest OSX and bootcamp with Windows 7 64-bit. It flutters on both OS. I have tried apple's forum, with no remedy. I had hoped software updates would fix this, whether in the form of OS updates, or boot camp updates, to no avail.

The condition is an intermittent and erratic change in the brightness setting, even when set at the highest levels, the display will step even brighter than what I can manually select as maximum. I say step, because it looks like a digital operation that is software related, and not hardware. It seems to be an issue of keeping the brightness setting stable.

Anyone else experience this?

jbmag45 said:

I assume this is a 2009 model having purchased it in February 2010. I am mostly confident this is an LED display. I am running the latest OSX and bootcamp with Windows 7 64-bit. It flutters on both OS. I have tried apple's forum, with no remedy. I had hoped software updates would fix this, whether in the form of OS updates, or boot camp updates, to no avail.

The condition is an intermittent and erratic change in the brightness setting, even when set at the highest levels, the display will step even brighter than what I can manually select as maximum. I say step, because it looks like a digital operation that is software related, and not hardware. It seems to be an issue of keeping the brightness setting stable.

Click to expand...

You are having the problem in OS X and Windows? It is hardware-related. There's absolutely no chance of it being software. If you are lucky, it's simply the brightness keys on the keyboard acting up. Try a different keyboard to see if the problem continues, or unplug the current one and watch to see if the problem continues to occur. If that doesn't fix it, then you need repairs. It's likely the LCD panel, a loose connection inside to the LCD panel perhaps, or much less likely the graphics card.

Try this: System Preferences, Displays. Remove the check from the box that states "Automatically adjust brightness.........." Let's see if the fluttering stops.

There is no automatic brightness adjustment, at least not under system prefs, display... Any where else I might look for conspicuous brightness level control?

You know, back in the day, brightness control was a knob on the side of the monitor. Much less problematic.

I thought your 2009 iMac had the auto brightness adjust for the monitor, apparently not. Take a look at your Energy Saver settings under System Preferences and turn off "Automatically reduce brightness.........."

I'll try it for a while, but I typically experience it 2-3 minutes after logging on/ powering up, and its not a simple dimming of the display after no use. I does it while I am using the thing. If I am at max brightness, it will go brighter, then dimmer and flutter between different levels, and then stop, all within a second, maybe do it again. I recall that I can open that Facebook photo viewer thing to get it to act up again. It will do it when watching youtube vids also.

jbmag45 said:

I'll try it for a while, but I typically experience it 2-3 minutes after logging on/ powering up, and its not a simple dimming of the display after no use. I does it while I am using the thing. If I am at max brightness, it will go brighter, then dimmer and flutter between different levels, and then stop, all within a second, maybe do it again. I recall that I can open that Facebook photo viewer thing to get it to act up again. It will do it when watching youtube vids also.

Click to expand...

You are experiencing this in OS X and Windows. That pretty much completely rules out any software-related issues, barring an amazing coincidence that you have identical software bugs in your OS X install and Windows install. It's hardware. If you doubt this, feel free to make a 3rd partition and install a virgin copy of OS X on it. Or on an external drive.

I'm reluctant to accept a hardware issue diagnosis, because I have tinkered with a few things, and somewhat affected the anomaly temporarily, and I am not really taking my computer for a ride down a bumpy gravel road either. With that said, I have looked at temperatures which notoriously affect faulty contacts, and from what other users claim, I see normal readings. I question the integrity of the bootcamp arrangement, as well as static ram in Bios, (PRAM) and think there may be a commonly used resource between windows and OSX. I honestly would prefer to eliminate windows altogether, but AutoCad favors Windows. The Mac version kinda sucks. I'm not certain that bootcamp will allow me to create yet another partition... is this what you mean?

jbmag45 said:

I'm reluctant to accept a hardware issue diagnosis, because I have tinkered with a few things, and somewhat affected the anomaly temporarily, and I am not really taking my computer for a ride down a bumpy gravel road either. With that said, I have looked at temperatures which notoriously affect faulty contacts, and from what other users claim, I see normal readings. I question the integrity of the bootcamp arrangement, as well as static ram in Bios, (PRAM) and think there may be a commonly used resource between windows and OSX. I honestly would prefer to eliminate windows altogether, but AutoCad favors Windows. The Mac version kinda sucks. I'm not certain that bootcamp will allow me to create yet another partition... is this what you mean?

Click to expand...

There is no shared resource. But by all means do what you need to do to satisfy yourself. No… you can't make a 3rd partition with Boot Camp. You should be able to split your existing OS X partition though using Disk Utility, then install a new copy of OS X to play with. But wait… if you really think there's some shared resource between your current OS X and Windows, then it should be shared with a 3rd copy of OS X, eh? Maybe just try booting off your install DVD, then see what happens. Unless that shares this resource also. Eh… you could always try resetting the PRAM for kicks. There is no BIOS though. It's EFI on Macs, and no method has been provided by Apple to access it.

ok, thanks for your insight, and attention to this thread. If this keeps up, I will resort to bringing it in for service.

jm

Seems to be fine once Adobe Flash player is removed. Just for kicks, I reformatted the MAC with OSX Lion, a complete HD erasure and reinstallation, wherewith no screen anomalies occured, until I loaded Flash player, then the problem returned. Same issue on the Bootcamp Windows OS. No youtube for me I guess.

my bad, it was hardware. just took it in for obvious display failure. good thing for apple care. $700 repair covered.

And folks want to know if Apple Care is worth it..... ;P