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My iMac arrived 2 days ago and yesterday I saw some flickering with sections going black for an instant, then one case where the whole screen went black momentarily.
This morning it started to get worse and I also got he menu bar 2/3 down the screen, with the vertical 'barcode' look above it. The mouse moved off the bottom of the screen and re-entered on the top. I took a screen shot but it looked normal and I had just got out my iPhone to video it when it went back to normal. Probably looked weird for a total of a few minutes.
I have called Apple Support in Australia and they told me to:
- turn off the Mac
- remove all cables
- press and hold the power button for 15 seconds
- re-connect all cables
- Hold the Command + Option + P + R keys simultaneously while powering on
- you should see the mac start and make a chime, then restart and chime again
They then told me that the next diagnostic steps (if the problem re-occurs):
- reboot with the install disk (put in OSX disk, reboot and hold down the C key)
- if problem continues then it is hardware, return to Apple
- if problem goes away then it is software
- if it is software do a re-install (archive and re-install is OK, but if that fails do a clean re-install)
- if still a problem return to Apple
Hope this helps others through the diagnosis. For what it is worth, I am now into a couple of hours after the initial reset and I haven't seen the problem re-occur yet. Still, it didn't show up for a day or so after it was first turned on, so it is by no means conclusive.
FYI I used Time Machine to install from a MacBook Pro machine I have. Did anyone else having problems do the same, or is it happening on a 'clean' install?
I also bought the iMac 27" over the weekend and started using it just today, to stumble on this issue (flickers, blackouts, line , displaced screen, ...) and the slow wifi issue.
Very disappointing ... i feel like i want to return the machine, but don't want to be charged the open box fee.
I will call Applecare and report back my experience. I guess this is what happens with early adopters !
You should not be charged a restock fee. I returned my unit without a restock fee, despite the store being unable to recreate the problem. Cite this thread and the thread at macrumors as evidence that this is a real issue, if they don't believe you, but don't let the 14d period lapse without doing something. At this point, no one knows if this is a hardware or software problem.
Woke up this morning and tried to take it out of sleep, but the monitor wouldnt go on. It seemed the imac was one because it would chirp at me when pressing some keys, but no monitor. I tapped the power button, essentially putting it to sleep and then the LED came on. No black bar incident this time (compared to one day ago). I'll keep tracking. I did not do any diagnostics yet, trying to figure out what exactly is causing the issue.
btw, to answer a newer post, I migrated a 20" 2007 iMac to this new 27" via firewire and the migration assistant. It was 10.5 OSX to 10.6 OSX.
Anyone else having issues, are they happening with a out of the box untouched install, or from a time machine or migration assistant copy to Snow Leopard?
I'm having this problem but only on my 24" LED Cinema Display which is connected to my 27" iMac. It happens after I wake the iMac from sleep or the display turns on after being off for a while. The flickering/tearing continues for about 10-20 minutes after start up. Is that consistent with what's happening for everyone on the internal display?
I've had my LED Display for a while and never had this problem when connected to my unibody MacBook Pro or my previous 24" iMac.
Good description. I am having the exact same problem. Bought a 27" imac last weekend and had the problem from about day 3. On the phone with customer support now to try and sort something out.
I have not recorded the issue, but will next time it happens.
Hope this problem is not endemic to the 27" range...
@[norrsund] +I'm having this problem but only on my 24" LED Cinema Display which is connected to my 27" iMac. It happens after I wake the iMac from sleep or the display turns on after being off for a while. The flickering/tearing continues for about 10-20 minutes after start up. Is that consistent with what's happening for everyone on the internal display?+
+I've had my LED Display for a while and never had this problem when connected to my unibody MacBook Pro or my previous 24" iMac.+
It proves this is a software issue.
Since your 24" LED screen has never experienced this problem on your other mac.
Try using your iMacs' screen only & see if it happens.
If it does, it will mean this is definitely something that can be fixed with a software update.
And I think that means... This topic is solved & answered.
@anthonyweeling: that's a bit of a logical stretch to say that it's a software problem just because the 24" screen doesn't show errors when connected to a different computer.
i don't know if you know this or not, but to drive an external display you have to attach that display to something they call a "graphic card" which while it may SOUND like "playing cards" (which are soft) is actually hardware.
without booting the computer that has the flickering issues from a drive with a known "clean" install there's no way to say "it proves this is a software issue".
mine flickered on first boot (on the "select your language" screen) a few days ago and started spazzing out completely a couple minutes before i did a search for "flickering 27 imac".
i hate the idea of having to return a 3 day old computer so i'd love for it to be a software issue, but i really don't see that being the case.