lighting element flickering on my iMac

Yes, the lighting element in my iMac is flickering, and it tends to go into sleep mode too quickly. Austin MacWorks either could not get the machine to duplicate the flickering or didn't spend the time needed with it. Don't know where else to turn, as they are an official Mac rep.

When you say the "lighting element", do you mean the backlight is flickering? How old is your iMac?

It is probably a faulty backlight board or graphics card. It could also be a power supply issue. Does your Mac display any other strange symptoms? Do you hear any buzzing or humming noises when you dim or brighten the display?

Thanks very much for responding, Adric. My iMac is two years old, OS X 10.6.8. And yes, I was referring to the backlight. It tends to want to go to sleep a bit too quickly, as well. Thought it was solved, when I followed earlier advice to change the display profile from iMac to Adobe RGB. Still some flickering, though it did stop for a bit.

If your iMac is two years old it might still be covered by Apple care, is it? If it is and you live in Austin, Texas, I suggest taking it in to an Apple store and let the genius bar look at it. (There are two Apple stores in Austin.) Your iMac uses LED lighting for its backlight so it would be unusual for that to fail prematurely but it's possible.

Thanks for the good info, chscag. Much appreciated.

The LED backlight boards are very reliable, the only time I change them is when Apple ships one with some replacement 27" displays. From your description it sounds as if the LCD is failing. With 27" iMacs the flickering symptoms are often a precursor to the LCD failing, either with no display or with extreme uneven brightness, the left side very dark. Hopefully you'll have Applecare.

Thanks Steve - good info. I take it that, if my Applecare no longer covers me, this is a very expensive fix? What you have described is spot on.

Mine flickers also, but happens maybe once every two days and when it does the flicker it is only one flash of brightness. Hopefully, that passes as normal behavior.

Thanks for the input, dotdotdot.