Q: New iMac 27inch screen flickering/tearing/shutoff

Thanks for the tip but unfortunately since I did the "online store" order, I have to do everything through them supposedly. Once they receive confirmation that the computer has been scanned for return shipment, they will "release" my replacement order.

I spoke with the staff at the Apple store some of who genuinely did not know there were some problem s but a couple that had picked up some info off the forums etc. I have just swapped mine and was told that perhaps this will be OK as it was a new batch so I will wait and see.

I certainly had no problems exchanging it but if this second one does the same I will wait until a solution is found before carrying this heavy item back a second time.
Good luck to you all that are having problems I will post if this stays stable or not in the next few days/weeks.

To those experiencing the problem with the 27" Core i7 iMacs, have you tried a fresh OS install from the included system DVDs? I thought I saw a brief flicker twice...both times after performing a Migration Assistant transfer from my 24" iMac running 10.5.8. I also noticed graphics performance degradation after migrating from my older iMac. After that, I decided to do a clean OS installation from DVD and I installed all of my apps from scratch. The graphics performance issues were resolved and I haven't noticed any flickering (touch wood) since then...that was late Thursday evening and my computer's been on and/or sleeping ever since.

Before you get too sure the problem is resolved, please note that my first flickering/blackout experience came 7 days after purchase, the second one 2 days later and the third one 6 days after the second one. So just when you think the problem is gone, there is again. Fortunately, a simple restart fixes it, at least for a number of days.

Hey everyone...

Having the same issue now and then on my imac 27" (Week 42)...
I'm in France so I'm gonna call apple tomorrow however as someone said earlier, I'm not sure they have figured out yet what's going on...so changing imac might not help...

I'll let you guys know !

Oh, I have very little faith that my problem's been resolved. In fact, I've already restarted my computer a few times for various reasons so it's entirely possible that the issue just hasn't had sufficient time to rear its head yet.

I just hope this winds up being a software/firmware issue because my iMac is perfect otherwise and, since it's a BTO model, I really don't want to have to go through the hassle of sending the damned thing back and waiting for a replacement. One thing's for sure...even if the problem does crop up on my computer, I'm not going to take any action until it's evident that Apple's found out the cause and the solution.

This is a good point. It only just occurred to me that I wiped my machine in preparation to returning it to Apple, and hence when I decided to keep it to test the 10.6.2 update I had to re-migrate my stuff again. In that process I hit the wrong button and did a full re-install from the DVD, then did my migration from a Time Machine backup after that. So, I have done a full-reinstall and I am on 10.6.2 and I have not had any flickering at all since.

I would be interested to know if anyone else can prove that this either has or hasn't solved their problem as I am still unsure whether to return my iMac during the initial period just in case the problem returns. I am now almost a week without a flicker or any problems whatsoever. Fingers crossed!

MarkyJ-

How long did your flickering take to appear on those occasions where you saw it? On the two times where I saw it (after my migrations), it happened right away. If you noticed it quickly prior to your latest clean install, I'd expect that you'd still see it happen quickly if the problem still exists. Keep us posted!

Message was edited by: Schwa72

Message was edited by: Schwa72

See my post a bit earlier today. I just got my i7 and migrated everything over including 10.6.2. I'm having the same issues.

Schwa72 - It took a couple of days initially (set up on 27-Oct, first instance on 29-Oct) then after the PRAM reset it took another 8 days (6-Nov) for it to appear again. Did re-install on 10-Nov and I have not seen anything since. If I make it to the end of the week with nothing then I would start to be confident that the problem has gone away but I think it is too early to call it just yet.

@ Bill P. -- It's a pain, but you should think about doing a clean install from the included OS X DVD. If that cures your problem, we might be on to something.

@ MarkyJ -- Man, if it takes that long for the problem to appear, that (to me) appears to be a software/firmware issue -- almost as if a file/driver/preference gets corrupted and a restart/PRAM reset/whatever fixes the issue until the corruption happens again. In my mind, if it were a hardware issue, it'd appear right away, and no amount of restarting/reinstalling/resetting would fix it.

But what do I know?

Message was edited by: Schwa72

Schwa72, thanks for the tip. I'll consider it if I can find the time over the next few days. Can I then migrate everything besides the DVD installed OS X over using my TimeMachine backup??

Bill

Message was edited by: Bill P. correcting error.

Just setup my iMac 27 Core i7 2.8 today which comes with 10.6.2 preinstalled. Worked fine for about 2 hours now I get the flicker (bands, at various places for under one second) and screen blackening (total blackout for about 1 second) about once every 2 or 3 minutes. A simple reboot fixed nothing and I have not yet tried the pram reset or reinstall of the OS some have suggested.

As someone who got a build to order from apple.com online this is pretty disappointing because the return process of this computer is going to be painful (weight and wait) and as of now it seems I very likely could get a similar flawed unit in the future.

Some have suggested this is certainly a firmware or software fixable issue (but it affects the lower 4650 as well as my 4850 card so is it really the card?). Others have suggested it is hardware (screenshots during flicker are normal) and will be a massive recall etc.

Thoughts? I can wait about 14 days but this darn beautiful computer flicker at least 4 times while I typed this message including blacking out once.

So disappointed in my nearly $3000 computer.

Bill P. - If we're assuming that some sort of file corruption is causing the flickering issue, then your Time Machine backup likely contains the corrupted file. So, I think restoring your apps and settings from Time Machine might just reinvoke the problem if, in fact, a clean OS install fixes it.

Having said that, I don't know exactly how Time Machine works (i.e. whether it creates an image of the entire system or just settings and apps -- but I suspect it's the former), but to be on the safe side, and to accurately test this theory of mine, I think you'd need to install everything from scratch. It actually didn't take that long in my case...probably about the same amount of time as each of the first two Migration Assistant transfers I accomplished took.

Message was edited by: Schwa72

quick update, a pram reset (option/command/p/r during boot) clearly "fixed" the problem for the last 10 minutes for me, my computer was flickering non-stop (ie. every minute or two) even after a reboot but now with the pram reset it is solid for far longer than before. i am sure it will return to flickering eventually but does the fact that a pram reset helped mean that this is likely a firmware / software fixable issue for apple? anything to prevent having to return this beautiful computer...