live52 wrote:
I have a similar problem that I'll describe hoping that it will contribute to this discussion and I'll ask a couple of questions. In December 2007 I bought an iMac 24 inch maxed out for speed and RAM and with the 750 gig hard drive. I had no problems until about three weeks ago when on startup I got grey hash marks all over the screen. When I selected the entire screen the grey hash disappeared and the computer seemed to run normally. I thought the problem was software related and began the long process of trying to find the culprit. Then two days ago I connected a video camera to the iMac to test the camera for the first time. It's a loaner from my school and is five years old. It seemed to be working fine. I then turned off the camera but left it connected to the computer by the firewire cable and put the computer to sleep. THAT was probably a mistake. When I tried to wake the computer it would not respond. There was a DVD in the machine and when I pushed the power button I could hear the DVD player makes it startup sounds and could hear the CD spin. Also I could hear the fans come on but the startup BONG never sounded. I disconnected all cables, pulled out the power cord for various lengths of time from 30 seconds to ten hours but nothing changed. I called Apple this morning and was told it sounds like a blown logic board which is what I was thinking. They will pick up the iMac day after tomorrow. When I talked to the Apple person this morning it didn't occur to me to ask about my chances of getting this repair done for free since I'm still within the one-year warranty period. I'll call when they open tomorrow morning but what are my chances of getting the repair done free? I've been using Macs since the Mac Plus came out but have never had a failure within one year so have no experience with the warranty. I did not buy Apple Care for this computer and never have but I will the next time. Thanks in advance for any comments.
As you have had it for nearly five years, it's unlikely to be repaired for free. But it isn't unknown for Apple to do so. There was an issue once where a batch of eMacs were built where a capacitor was used that could fail. They were aware of the problem and if one's eMAc was one of that particular batch, it was indeed repaired by them for no charge. So, if there is a problem known to Apple, it might be fixed at little charge.
I would be particularly interested to know how you get on because three days ago I upgraded from Snow Leopard to Mountain Lion, since when I too have been getting horrible vertical lines onscreen.
If I move a window around a screen, it fills with these lines. Sometimes, so does the dektop.
https://dl.dropbox.com/u/11373233/MacDiscussions/Screen%20problems%20post%20Moun tain%20Lion/ScreenFault.pdf
I'm hoping it is due to a software conflect because a) I think it started when I installed Mountain Lion and b) the problem seems to go way if I run the iMac in 'Safe Mode'. My 24" iMac is about a month older than yours, from what you say.