Wow, that screen shot with the pink gradient rectangle . . .
Wow, that screen shot with the pink gradient rectangle is EXACTLY what I have seen on my 24" iMac 2.16ghz Intel Core Duo. I am glad I'm not the only one, I will direct some people to this thread to explain my problems. I have had to replace the logic board twice under AppleCare.
Questions:
Are the people having this problem all using some kind of Windows emulation, i.e. BootCamp, Paralells, or Fusion? I ask this, because resetting the PRAM helps me for about a day or so to escape the problem. Resetting the PRAM (3 consecutive times) apparently resets the firmware on the Logic Board. I'm wondering if some kind of windows/Bootcamp/Emulation driver installed slowly messes with the firmware controlling the fans and allows for overheating. I'm no expert, it's just a theory.
Comments: i totally agree that if the problem was a cable, taking a snapshot wouldn't show the issue, the problem is definitely in the computer, not the monitor or the cable.
This is why you should always buy applecare. Of the the Six macs that I have had only two of them has never gone in for repair. I've had two drives replaced, three logic boards, one cd drive and RAM. Tip: Buy your Applecare on Ebay at almost a 40% savings. Unlike most Apple products, the markup on AppleCare is pretty high, and motivated sellers can cut a pretty good deal. Good luck, my iMac is going in next week again.
