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

Tom1631 at the bottom of page three of this thread:
http://discussions.apple.com/thread.jspa?threadID=2274341&start=30&tstart=15
has just had this done and I'm awaiting the same repair - let's hope it is permanent fix.

My story is the same. I live in Denmark as well, and I am now waiting for my 2nd iMac. I arranged an overlap, so I can keep the "old" iMac for 5 days after receiving the new one. This way I can transfer documents and settings easily. I also got a 100 euro compensation. Had to ask for it, though.

Swe_Theodor, how did you get your machine apart, and was it difficult, and lastly does taking it apart show any "signs" that you did so??

As for the magnet theory, is there any relationship between these problems and using the internal speakers. I did the first few days I had mine back in mid Nov, and did see some very small flickering. I since changed to my external speakers and have been flicker free. Just another thought, I never put these two together until now.

I use External Speakers. I still get intermittent Flicker & I have Yellow Tinge disease. If I PRAM or run Onyx the Screen Flicker will not return for a couple of days. I shut down my iMac every evening.
I have the 21.5 NVidia. Week 45

Eden,
Any effect the speakers may impart... would present - whether speakers are working or not ?
(magnets)

I kind of figured that would be the case. The whole Onyx and PRAM thing is very mysterious I must say. I'm an electrical engineer and I still think there must be some common hardware in all these machines or it still could be software based, but I would not think that for the yellowing however.

Well the internal speakers would be the creator of a magnetic field via the voice coils, if that were the case, but it was just confirmed not to be (of course). External speakers would not cause this field, or at the very least not in the same way due to different proximity. What a mystery, I have read this entire thread and keep updated daily (what a geek huh). Nothing is consistent here at all. Just something common to all the various models mentioned. Weird . . very weird.

thxdude --
I had the same replacement made. I regret to say it made no difference; the flickering/black-out problem soon returned.

I also (on a second repair on the same iMac) had the video card replaced. No difference. In both cases, the problem returned within three days of use.

(I suppose in my case Apple could have used cannibalized parts from other flickering iMacs. They don't seem to really know -- or acknowledge -- what is going on, so they couldn't have tested the parts for the problem.)

What if it turned out to be interference with the Magic Mouse?? L.O.L. I'm sorry! I had To!

edenorchestra:

it is not my disembodied Imac on the pictures,i have held off ordering one until there is a definitive fix of the current problems. if you are interested in the entire disasembly you can view it here:

http://www.ifixit.com/Teardown/iMac-Intel-27-Inch/1236/1

i still do believe that the speakers magnets couldd interfere with the cable, but the most likely explanation i think would be the fan/heat isssue, at least for the yellow tinting. one way to explore this further would be to compare different datas on temperatures from people who a) have no problems and b) the ones that do.

we should bear in mind that apple did reduce the size for this model whilst cramping more raw power in it. in the teardown link there are also pictures of the heatpipes that the logic card uses but i cannot tell how these would seem to be placed inside the computer. although it is quite easy to imagine that one such heatpipe from the processor or/and gpu would create a higher amount of heat at a specific place.

edit: the heatpipes for cpu and gpu are oriented toward the top of the case, would not directly affect lower parts of the compupter unless all that hot air is being pushed downwards.

Message was edited by: Swe_Theodor

Doc,
I still suspect this is all to do with an introduced scenario - after factory shipping;

viz;
a) User software or parameters - installed during data transfer
b) Rough handling or abuse - during transit to final destination.
c) Snow Leopard's control of Users imported Apps.
d) User attached peripherals and/or associated Drivers.

#W8947.....

Received Imac 27" 2.8 Quad in the mail end of November. Worked amazingly for a month. No static, no flicker, like I said no issues. A week ago while searching a external hard drive (no applications running). The finder reports an error. Spinning color wheel appears....for way too long... I restart. Screen goes blue....Refuses to restart. I manually shutdown. I wait.................When I restart, the chime comes on but, nothing on the screen. I repeat......chimes, no screen. I unplug all external hardware....I repeat....nothing but chimes...I call apple support we go through the steps and reset everything we can. (She was very nice) Same issue. She suggests to bring it in to have it looked at. (i had it too long to exchange) I brought it in as soon as I got off the phone.

They are replacing the videocard, but said it might be the logic board.....I havent gone through all the threads, but I havent noticed my problem??? I am sure it relates....

I keep posting when I get my computer back

Well, (a), (c), and (d) are excluded. Both myself and others have seen the problem on virgin systems with nothing attached. I disagree that (b) shipping damage is more likely than a manufacturing or firmware fault, considering the specificity of the problem and the failure of any technician to open up the case and see anything out of place.

I personally think there is some component which cannot deal with some less-than-ideal-but-still-within-normal-operating-parameters variation. Maybe the variation is electrical current, or proximity to cel towers, or extra-strong-speaker magnets, or invisible space monkeys. Whatever it is, it's something that every other computer in my house is completely immune to. My iMac should be too.

you have the problematic space monkeys in the us too!!!!!!

i dont believe its an external influence!! more like a manufacturing fault.

surely they had a prototype of this imac and stress tested it for a while though???

but the leap between prototype + stresstesting to mass-manufacturing is quite big, especially since one most likely is done halfway around the world from where the other one is. who knows what can happen between those two events?