24" iMac - can't change brightness

[guybrush03]

Hi,

I setup my new 24" iMac today and was trying to change the brightness, but am having no luck. With the hotkeys, I get the brightness meter changing (and the settings stick), but no change in the brightness; the brightness slider in Display settings doesn't work either. I've run the normal and extended hardware tests, and no issues were found. Panel timeout works fine, although the brightness never dims before the timeout like it should. Turned off all the room lighting and it's definitely not changing; I had to exchange for this iMac too, and the previous one worked fine.

Any ideas on what could cause this? Last thing on my list is software updates, but it's curious that the previous system worked fine (both are from Best Buy, I would assume in similar software states). Been searching the net and forums for awhile, but haven't seen anyone else with this problem yet .. hope I don't have to exchange yet again (this one has no stuck pixels) .. *g*

thanks,

guybrush

 

[Sebby]

Try resetting the NVRAM.

 

[guybrush03]

Try resetting the NVRAM.

Tried the NVRAM/PRAM reset (no change), and also the super I/O reset (no change). Also checked the software update list, didn't seem like anything that would affect this (iTunes, Java, AirPort, etc).

Any other experiments to try? I figure I'll mess with tonight and exchange it tomorrow if no luck. Thanks for the help in advance!

guybrush

EDIT (3/21): Apple support also had me try safe boot and reinstall OS from scratch - no change in either case.

EDIT (3/22): For the sake of future readers, I never found a way to fix this .. so suggest doing an exchange/return if you see the same issue.