i5 27" imac display doesn't turn on

Hi,

This issue just cropped up for me this morning. When I go to turn on my recently purchased (Feb 2011) core i5 27" iMac, the screen doesn't turn on. Instead, it remains black until I hit the power button again, after which it will usually come to life. It sometimes goes black again without any warning. I can usually get the screen to come back to life if I hit the power button. However, I have an older 24" cinema display hooked up as a second monitor, and it always comes to life when I start up, and never goes black like the iMac display. Anyone else having this problem? Are there any known/recommended solutions?

Thanks!