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27-inch / 27" iMac Random Shut down

SPECS:____________________________________________________________________________
• 27" 2.8 GHz Intel Core i7 / 8gig / 1TB
• OS 10.6.3 (about to update to 10.6.4)
• All firmware updates have been applied according to software update
• 3 external drives: 1-320 gig 800fw / 1-TB USB 2.0 / 1-500gig USB 2.0

INFORMATION:____________________________________________________________________

I've been running with this configuration ( 3 extra drives) since approximately December with no issues. Out of the blue... only running Aperture and Safari - my iMac JUST SHUTS off- WITHOUTwarning. It acted as though I was running a MacBook and the battery going dead/asleep. That's how random and sudden it shut down - NO WARNING. I did have the iMac asleep for about three hours before coming back to it to start working again when it shut down, but it should have even been cool.

I only started reading around on the web to see of other incidents after this random shut down this evening, but I can't find anything specific. I've found A LOT of similar things - all seemingly related to "HEAT."

And heat seems to be a certain issue recently - in the last day or two. Today I noticed my top back side to be hot, which isn't uncommon, however, it became so hot I really wasn't able to keep my hand on the top back. I've also noticed A LOT of spinning beach balls, and lots of processor delay! Heat??

There are NO energy saver pref's set to automatically shut it down. The power was and is firmly set. There are no network settings, nor access to the iMac to have it shut down. It is not shared with anyone on the network.

SUMMARY:___________________________________________________________________________

• Today, I grabbed a couple temp / monitor widgets and am trying to watch the data. All components seem to be at/around/below 140 degrees F with ambient air at 77 degrees. I don't know numbers, but that all seems reasonable.
• Going to update to OS 10.6.4 (doubt that's it!!)
• I'm going to run the hardware test from my disc to see if ANYTHING. 8-p
• AND... I'm going to call Apple to set up a case. It's still full under warranty, and I have 2 more years of AppleCare on it. But there's been too many things pointing to hardware to call this a software issue.

I've dodged all the display issues with my iMac, but now.. I'm a bit hacked knowing how much I spent on this thing, with the initial DELAYS I went through, ordering it before it had even been released!

?? QUESTION ??_____________________________________________________________________

So, has anyone else been having this issue, heard of a solution, seen anything on Apple's website of known issues ??

Barry
( Grumbling bout my Mac)

Which one of twelve??, Mac OS X (10.5.6), ever hear Newton?!! ;-) One of those, too!

Posted on Jun 22, 2010 8:59 PM

534 replies

anjosef

Level 1

0 points

Jan 10, 2011 8:43 AM in response to Berry with an A

I just bought i7 27 inch iMac with 16 gb of ram 4 days ago, and yesterday my computer shut down twice for no reason at all.

I can see so many trouble shooting solutions available on these forums. I thank everyone who has tread this path before me.

I just wanted to add my name to this growing list.

Fatbot

Level 1

0 points

Jan 10, 2011 9:13 PM in response to anjosef

My 27" iMac, about 13-14 months old, (just out of warranty of course!) Started randomly shutting down a few months ago. Took it back to the shop, and recieved a call from their tech support yesterday saying that the Logic Board was busted, and not worth the repair as it's basically the cost of a new machine...

I really don't want to have to buy another iMac within under 2 years! Not sure of my chances of pleading my case to Apple (going to give it a shot), but an iMac dying in such a short period of time is just not right!

I also just wanted to add my name to the ever growing list.
It almost helps knowing I'm not the only one, but... That said, if I'm not the only one, why isn't Apple doing anything about this!?

denso1

Level 1

0 points

Jan 10, 2011 9:50 PM in response to Berry with an A

I'm having the same issue with my iMac 27" i7. I mainly notice it does it when I leave the system idling for a day and upon waking it up it then goes black. I then have to press the power button for it to turn back on, once on it just resumes from where I left off. So I have like a week or so until the factory warranty is up, how should I state my case with Apple? This machine was a little too expensive to be acting this way IMO.

This has happened roughly 6-7 times..

Jeff Donald

Level 7

28,997 points

Jan 12, 2011 4:17 PM in response to denso1

I'm going to reply to these threads as I see them posted or come up on the discussions. I have a July/Mid 2010, iMac with the i7 2.93 GHz model. I've been using it with 16 GB of ram for the last three weeks (OWC brand) and having no issues with shut down, etc. I use Photoshop, Lightroom heavily and see the temps get upwards of 150 F with no issues. Sorry that others aren't so lucky, but not sure that it is Ram related.

Jan 13, 2011 1:31 AM in response to Jeff Donald

I've been using it with 16 GB of ram for the last three weeks (OWC brand)

This ram does not happen to have Samsung or Hynix chips?
OWC sells a lot of different brand s of ram/chips.

peterwillem

Message was edited by: peterwillem

Jeff.C

Level 1

0 points

Jan 17, 2011 9:05 AM in response to Jeff Donald

@Jeff Donald. It has long been determined to be a RAM issue. Are you sure you didn't purchase Samsung RAM from OWC (which solves the problem)?

I went through a couple batches of OWC RAM with the same issue for a few months. As soon as I replaced it with 16GB of Samsung RAM, the problem went away (and has been running great for two months now).

Apple engineers are aware of the issue and are working on a solution (but still no word from them yet on said solution). My guess is that they are working with all the third-party RAM vendors who are issuing the RAM chips that are giving problems.

You mention that you've only had the RAM for the past couple weeks. Maybe they solved the problem a few weeks ago and only people with recent OWC-brand RAM won't have a problem going forward (I am only speculating, but it's possible and hopeful).

Jeff Donald

Level 7

28,997 points

Jan 17, 2011 9:39 AM in response to Jeff.C

OWC currently offers 3 brands for the mid 2010 27" iMac. The sticker has a big OWC on it and the part number from the invoice is for the OWC brand on this page:

http://eshop.macsales.com/shop/memory/iMac/2010/DDR321.527

and not the Samsung or NuRAM offered on the same page. I teach Lightroom and Photoshop and it gets a pretty heavy workout almost every day with no issues or shutdown.

It's impossible to say about fixes with the ram. We'd have to know the production date codes etc. and most mfgs. are not that forthcoming.

Jeff.C

Level 1

0 points

Jan 19, 2011 8:06 AM in response to Jeff Donald

@Jeff Donald, A user by the name of Gianfri has confirmed that OWC recently "tweaked" their RAM to address the issue. So you are likely one of the lucky ones to get the RAM that has been addressed by the "tweak" (whatever that tweak is).

reference: http://discussions.apple.com/thread.jspa?threadID=2548180 (see near bottom of page 13 in that thread for the comment from user Gianfri).

For those still having the problem (with OWC RAM), I'd suggest contacting them to get the RAM replaced (OWC gives lifetime warranty on their RAM, so they'll replace it).

Message was edited by: Jeff.C

Chalkers

Level 1

0 points

Jan 25, 2011 4:41 PM in response to Berry with an A

Join the train.... replaced my old white Imac with NEW Imac i7... brought in November immediately upgraded with Corsair memory from Amazon... BAM! Random shutdowns every day!!

You would think if you fallowed the RAM upgrade instructions and specs as per Apple inc...

"iMac (Mid 2010): Memory specifications"
http://support.apple.com/kb/ht4255

Apple support - do this, do that, install your operating system again -

Like I have so much time in my life!!

At least the internet shows the problems for what they are..Maybe apple should take some responsibility or at least acknowledge the problem and stop wasting peoples time.. OR Better maybe fix the problem!!

Ordered a new power supply for my 2007 White Imac at least it was reliable!!

Next step? maybe count my losses and order memory from OWC??

AxMstrLP

Level 1

5 points

Jan 27, 2011 12:17 PM in response to Berry with an A

I encountered the same problem. 4GB installed by default and it was rock solid. I added 8GB G.SKILL RAM and had my frist random power-off about 4 hours later. I've already got an RMA and it's going back.

Does anyone know if Newegg's Samsung DDR3 SODIMM is a good choice? It's part # MV-3T4G4. I don't know what the part number is on the IC's.

Other than the $600 8GB upgrade from Apple, what's the consensus on the best source of upgrade RAM?

http://www.newegg.com/Product/Product.aspx?Item=N82E16820147068&cmre=samsung_ddr3-_-20-147-068--Product

italosan

Level 1

0 points

Jan 28, 2011 1:00 AM in response to Berry with an A

Same problem here with an iMac 27 with i7 and 16gb of aftermarket RAM with SSD. And, of course, I have the same issue of the random, several shutdowns (no restarts). The only thing I can add is the fact I experience this kind of problem when i'm NOT playing world of warcraft. Sometimes I have very long playing sessions (up to 5/6 hours of gaming) and in this case no shutdown happens. Hope this can add a clue to some one

ChoPraTs

Level 1

41 points

Jan 28, 2011 4:06 AM in response to Berry with an A

The shop (Macnificos, Spain) where I bought 4 modules of 4 GB of Ram that causes random shutdowns on my iMac 27, has been in contact with the distributor and manufacturer of CSX Ram because some other clients experienced the same problem.

They affirm that shutdown problem is an electric problem of iMac, not a problem of Ram modules, and they are sure that can ocurr when the machine has 16 GB of Ram installed and with some specific modules. CSX can't found any problem on their modules, so they think their RAM is OK, and assure that the problem is random and also can ocurr with Samsung RAM. They think perhaps my modules are defective. I'm not agree with this explanation.

They accept to change my four 4GB modules of CSX RAM with four new identical modules. I will try it all next week, and I will warn you if the problems persist with the new modules, but I'm sure that shutdowns will be continued ocurring because the modules that they're sending to me are identical to that already I have.

ChoPraTs

Level 1

41 points

Jan 31, 2011 2:58 AM in response to ChoPraTs

Received today 4 new modules of 4 GB CSX RAM. Same problem, after installing, random shutdowns.

So, no defective RAM, sure incompatibility Issues.

With 12 GB, 8 GB (2 modules) or 4 GB (1 module) no problem. With 16 GB, impossible to work.

Waiting a response from the shop for the possibility to change this RAM and get Samsung which does not produce shutdowns according to report several users.

Dakuga

Level 1

0 points

Feb 1, 2011 5:15 AM in response to Berry with an A

27", 2.93GHz, Core i7, 2TB + 256 SSD Hardrive and 16gig Ram
Just to add another unhappy imac user: I put 4 4GB NuRam from OWC and after that it started to shut down. As a matter of fact, the most time it shuts down is when i am using Itunes or when the AppStore app is open (i would say this is 80% the case). I hope Apple will fix this issue soon!

jorjazz

Level 1

0 points

Feb 3, 2011 6:10 AM in response to Dakuga

first 27"imac i7 2.93 was upgraded with owc 4x4 ram sticks...started shutting itself off. 2 power supplies and 1 logic board later same result..imac was replaced last week and I added a 1500APC for good measure and the shut downs continue. I am still using the same ram, so I guess I will remove 2 of the 4 chips and see if that helps. I would love to exchange this piece of s**t for a mac pro!

27-inch / 27" iMac Random Shut down