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

i think people were trying to ascertain whether there was a faulty few weeks, but it appears there isnt

Hey! Did it occur to anyone that maybe Apple just kept sending the defective Mac back to him hoping he wouldn't notice? ;0)

Good grief, this display thread "rocky mountain horror picture show" written all within it.

Oh yea, we were discussing the 27" flicker and blanking display problem....

Mike

You are right schwa72, better to have the fans too fast than too slow as they are very silent but it is a little bit weird (even if it doesn't matter) that yours are so high. I wonder if there is other people in your case.
My fans run more like the others, for the CPU, 940 rpm in normal use and up to 1500-1600 rpm if the CPU temperature reach 60-65°C (ambient air is around 20°C). Optical drive at 1000 rpm and hard drive at 1100 rpm.

Happy New Year to everybody and let's hope Apple find the solution to this strange problem as this iMac 27" is truly a fantastic computer.

i think we're missing the point, and going away from what the topic is all about: flichering. And most had just prooved that 99% isn't thermal related.

I ordered an imac on christmas day, it will ship on january 12th. Now, i read a couple of pages ago about this "new LCD and cable connector" replacement for faulty imacs.

Do you think this mid-january imac will be already fixed or just be faulty like week 50-51-52 ecc?

Thanks in advance.

Knowing the week of production really probably doesn't mean anything yet..........but it will, at some point.

Once the cause of the problem is determined, We would assume that any machine manufactured after that point would be free of the issue, so particularly for those who choose to purchase from a retail outlet, rather than direct from Apple, the serial number, which indicates the date of manufacturing would be extremely important.

One thing I am curious to see, is whether or not week 01 machines will be listed as W8901, or W8953, or some other variation of the serial. W9001, or W9053.

One would assume that if the cause of the issue is a defective gpu, then all of those components still on the shelf would either be refurbed, or trashed, and not placed in units manufactured after the date the problem was resolved.

Any one have their iMac 27" not built in China? Seems like Apple outsourced all I5 and I7 machines to China, unlike the 27" C2D which has shown to be assembled in the States. I highly doubt apple would send a knowingly defective product. Something got screwed up in the manufacturing process over in China, because I have yet to hear any 27" imacs made in the states having issues. Hopefully Apple will iron out issues of QC over there.

Schwa72........uninstalling the Fan Control preference pane will not likely reset the fan speeds to default, unless you have also uninstalled the application itself, it will simply create a new preference pane.

You should be aware, there are some issues with SMC Fan Control, and Snow Leopard, since the app has not been updated since 10.5.

Other users have reported an inability to reduce fan speeds, even after deleting the application, some of them are running considerably higher than yours.

Here is a link with a little more info.

http://reviews.cnet.com/8301-13727_7-10327540-263.html?tag=mfiredir

Although it probably doesn't hurt to run the fans at a higher speed, I would be concerned that it may shorten the operational life of the fan, creating more problems down the line.

Schwa72 wrote: According to the Fan Control preference pane (my screenshot is published above), there is no way that the fan speeds can drop below 1200/1200/1000 RPM, regardless of ambient temperature.

FWIW, my fan speeds (before I returned the i7) had a min of:
ODD: min: 1000 (actual: 998 rpm)
HDD: min: 1100 (actual: 1097 rpm)
CPU: min: 940 (actual: 3899 rpm)

pazuita wrote:
Schwa72........uninstalling the Fan Control preference pane will not likely reset the fan speeds to default, unless you have also uninstalled the application itself, it will simply create a new preference pane.

You should be aware, there are some issues with SMC Fan Control, and Snow Leopard, since the app has not been updated since 10.5.

Other users have reported an inability to reduce fan speeds, even after deleting the application, some of them are running considerably higher than yours.

Here is a link with a little more info.

http://reviews.cnet.com/8301-13727_7-10327540-263.html?tag=mfiredir

Although it probably doesn't hurt to run the fans at a higher speed, I would be concerned that it may shorten the operational life of the fan, creating more problems down the line.

Pazuita-
The Fan Control pref pane didn't install an associated application. But I did remove it and uninstall SMCfancontrol before I reset my NVRAM and SMC. Besides, my fan speeds after the computer slept all night were as follows (right at the minimums predicted by the Fan Control pref panel back when I started this, I might add):

So, it seems that, in my computer's case, the fan speeds simply aren't going to drop below 1200/1200/1000, regardless of temp. I'm fine with that, but it is curious as to why my absolute minimums are different that other folks' minimums.

I think the vast majority, if not all of the i7 & i5 iMacs are built in China, don't know the numbers, don't know if anyone does. If your serial number starts with a W it's made in China.

My defective, flickering and blacking out iMac, is on it's way to being replaced with, what I'm assured by the people at Apple Store sales support, will be a new, freshly made in China machine. A previous poster claimed defective machines are replaced with refurbished machines. I was assured in no uncertain terms, that is not the case.

I seem to be one of the 1% of flickering iMac owners who's computer seems to be affected by heat. The behaviour, so far, has only presented itself once the gpu temps get above 80c with my fans refusing to respond by increasing speed beyond the preset minimums.

Oh well, not my problem anymore. I'll have to wait for the delivery of my new machine to see what exciting new, or depressingly old problems may present themselves with it.

I think you have a good handle on the issue. I considered installing FC, but after cross referencing my conclusion is that installing FC would not be a wise decision. I can't imagine that Apple hadn't accounted for most if not all scenarios in which the i7 would operate. I personally can't see why people try to outguess the smart people who collectively developed the i7. Sure, there are issues with the i7 and others, but imho those people are infinitely smarter than all of us put together ( especially when you consider my IQ : )

This is getting ridiculous now. Guys, this is not a thread for CPU or GPU fan speeds this is about the flickering problems on the new iMacs. If any of you who are heaving a 4 page conversation of fan speeds now had read at least a bit of this thread then you would know that a large percentage of the people also get the flickering right after startup/wakeup. So it is very unlikely that this is a heat issue for most of the people affected.

With your talks about fans you are dragging this thread off topic and pushing it out of focus. A lot of people have worked to get some media attention on this.

So please, if you have not done so, read the posts or if you want to continue, just open up another thread with "How to tune your new iMac CPU fan" so that the others who have problems can continue to post them.

I have a week 46 i5 that's 3 days old and has exhibited this issue twice in the last two days. Sleeping the machine and bringing it back up seems to correct the problem for the immediate future. This is still unacceptable for a brand new machine, especially one of this price.

Has anyone who has gotten a replacement gotten one that didn't exhibit this problem? I've heard of many who have gotten one or more replacements that all exhibited the problem, but in my review of this thread, I haven't found any that have gotten a non-flickering replacement. If this is true, it seems to indicate that the large majority, if not all of them, have this problem. Is getting a replacement really worth it if the odds are that the new one will have the same problem?

Has anyone installed win7 on their flickering iMac and had it flicker under Windows? Could be an interesting experiment.