New iMac 27inch screen flickering/tearing/shutoff

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...

@ canyonblue - I'd recommend first trying the PRAM reset and then reinstalling the OS from the included DVDs. Let us know what you find out!

canyonblue - That's good news, and I agree with your supposition that if a PRAM reset fixed the problem (or at least significantly reduced its rate of occurrence) then that points to a firmware/software issue as opposed to a hardware one. Please keep us posted...and I also recommend either phoning Apple or submitting a bug report -- what you've discovered might help "the engineers" (who are supposedly hard at work on this issue) narrow down the culprit!

Schwa72, I have not used Time Machine on this new Mac yet, happily. So my old stuff should be ok.

FYI, no problems for me today, my third day with the new i7. Happened once on Friday and once again early in the morning on Saturday. All I have done is boot up from the DVD to run Disk Utility (nothing found) and repair permissions. Meanwhile, I'm waiting and waiting like the rest of you.

It seems that some systems are having a greater frequency of this occurrence (lines and screen blanking out briefly) than others. On the two times that I observed this I did an immediate restart which seemed to solve the problem. If it happens again, I plan to let it go for a bit and monitor it.

Bill

well i will refrain from posting further updates for a few days to see what happens but clearly, clearly the pram reset did something positive. i was flickering every single minute and i rebooted and the flickering continued with no improvement. i then rebooted and did the pram reset and now the machine hasn't flickered in over an hour. the machine has never been shut down so it isn't a heat issue, clearly the pram reset improved the issue. now based on this forum it appears resetting the pram is not a true fix and i bet the flickering comes back in a day or two but at least i now have a way of preventing it from being constant and i have hope that i won't have to return this machine. i hope apple can at least address the issue shortly even if the fix takes a bit longer, it would be good to know it won't require a recall. i'll let you know how i am doing in a few days.

canyonblue, that's definitely good news, even if it doesn't prove to be a lasting fix, at least it's one **** of an improvement. Please keep us posted!

Bought a new *27" iMac 3.06 Core Duo* from a well known UK department store (JL). After several hours of continuous use with the brightness set between 6-8 bars (halfway), Intermittent screen flicker both horizontal and vertical occured with the occasional black screen for a brief second. The problem persisted and became more frequent, especially after waking from sleep.

After reading this forum, I wasted no time in returning the item back to my local well known department store as faulty (the day after i bought it). Although the issue did not occur in the half hour of their technical team testing for the fault, I did show them this forum, and they exchanged it for a fresh new (not refurbished!) model.

I can safely say (with finders and toes crossed whilst clasping a block of wood), the new model has not flickered once - i've had it for 3 days now!

For the record, the new exchange was picked from the same batch of iMacs as the faulty one! ..

If you've got a dodgy one take it back quick for a replacement and within 28 days to avoid receiving a refurb (in most cases)!!

Well the pram fixed lasted 2 hours. All the flickering / blackouts returned. I once again reset the pram and again it is fine for the moment. I am 2 days into my 14, but having bought online it is going to be messy with the return. I am going to wait a few extra days and see if any more info comes out before I make a move, I would sure love to hear from people with the 27 who simply don't have any problems.

canyonblue, it seems like the last thing you can try at this point is to do a clean reinstall from the DVDs that came with the computer. I've read that clean installs have resolved other issues, so I guess it's worth a shot. Bear in mind that you won't be able to restore your programs and settings from Time Machine because, if it's a software glitch that's causing this, it's likely you'll reload the glitch when you restore the Time Machine backup. Good luck...hopefully Apple will announce a fix next week.

i have no doubt apple will fix this one way or another, but i want a new computer that works. if i have to box up my computer and risk damage / scratches in a month for them to fix it over a few days with a GPU swap or something i would be better off returning it now. if this is something apple can fix with a firmware update or software update i hope they tell us soon, even if the fix takes a bit longer because then i would hold tight.

Just keep in mind that after your 14-day grace period, Apple will attempt to FIX the computer first (as opposed to just replacing it)... unless there is a huge recall or something. At least this is what I was told by tech support. So if it is a hardware issue, do you prefer taking that chance and potentially having to send it in for "free" repairs or would you rather just have a new iMac made from a different "batch" that most likely won't have the same hardware issues? I suppose that is the question...

Well, there's the rub. Who's to say that if you decide to return the computer within your 14-day window that you'll get one that's any better? If it is a hardware issue, there's no indication that Apple's already identified the issue and implemented the fix in their manufacturing line (again, what do I know?). I guess since you've already verified that you have the problem you really have nothing to lose, but I certainly feel your pain. I'm gonna be hella ****** if I have to eventually return my computer for a repair only to have it come back with scratches and/or other damage (dust under glass, etc). I just hope it turns out to be a firmware/software issue, that's for sure. Maybe we'll find out more tomorrow once some other folks call Apple about the problem.

the more i think about this the more convinced i am that it is a hardware issue even if it can be fixed by firmware or software. after all how can you explain that some imacs don't seem to have a problem at all (it isn't every imac doing this, although this thread is big it pales compared to the total owners of the new imacs), others only have it every few days and others like mine get it every few hours and then display it every minute. the flicker and behavior is similar but the magnitude is totally different for everyone. i would suspect this is some sub-component issue and often work arounds via firmware and software are possible but not guaranteed. i am still thinking but i really might have to send this back sooner than later if only to get the exchange moving since quad cores are rumored to be a 3 week wait for exchanges right now.

TRujder

Apple's normal practice with faults is to keep quiet and admit nothing until they have a fix.

Apple users have a great deal of difficulty admitting to themselves that there can be anything wrong with their Macs, so they usually sit on them until it is too late to do something about it.

I was forced to put up with networking problems on my previous 24" iMac for over 6 months. Apple would not do anything except offer endless phone support that told me twice to completely backup and reinstall which I knew was useless.

It was only when after 5 months the power supply also failed and was unsuccessfully repaired, that I was able to successfully get Apple to replace the unit.

I have had no trouble with the replacement iMac, and Apple restarted my AppleCare as of the delivery of the new machine, which I thought was decent of them.

Peter

ok that does it, tomorrow i call apple and send it back (as is my right in the first 14 days). maybe apple can fix my machine good as new with a software patch but i would rather a computer work right out of the box and apparently some 27 inch imacs do, so i would rather have one of them. this hurts.