24" Al iMac Screen Keeps Going White, Hard Resets Required

[Astral Cars]

Three times in the last week or so my iMac's screen has just turned white (once with almost a ribbed pattern with thin grey vertical stripes evenly interspersed) and become completely unresponsive, with the only option being a hard reset. It's happened under a variety of conditions: while surfing in Safari, while working in Aperture, and once without doing anything (I was on the phone sitting by my computer). Each time I've restarted it everything seems to work fine for a couple days, but then it happens again. I've never seen anything like this and I figured after the third time it's time to ask for help. Does anyone have any ideas?

[Matthew Yohe]

Did this start after installing 10.6.4?

[Astral Cars]

Nope, started before. I have since installed 10.6.4 hoping that for some reason that would fix it. No dice.

[dexthageek]

Nope, started before. I have since installed 10.6.4 hoping that for some reason that would fix it. No dice.

Could be the GPU :(

[Astral Cars]

Any recommended action? The problem isn't exactly repeatable, nor is the computer particularly portable so I don't know about just bringing it into an Apple Store. Also, it's about two years old and I don't have Apple Care, so how much might that sort of thing cost me?

[shujin]

My 20 inch imac has been doing the same thing for a couple months now. I did a power reset by hold control+p+r at start up. But that did not do anything either. I still have a couple months of apple care left. Looks like I am going to the apple store this week.

[Astral Cars]

Anymore ideas out there on this? Shujin, have you had any luck figuring it out?

I went about a week and a half without it happening, but now it did twice today. It's really annoying and I'm not sure what to do because it's not repeatable and an iMac isn't exactly convenient to bring into an Apple store. Are there any hardware tests I can run?

Oh, and I don't know if it matters, but the most recent time the screen went white, I had music playing and while it continued for about a second it then started to skip and play the same little blip over and over until I reset it.

[booeysnooman]

This happens to my MacBook all the time! Nice to know I'm not the only one:). What I do whenever this happens is I push the screen back. Sadly though, whenever I take my hand away, it does it again! SO ANNOYING!!!!!:mad: Anyway when you push the screen it does work but I would like help for it to actually stop.