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27-inch / 27" iMac Random Shut down

160428 Views 498 Replies Latest reply: Jan 8, 2014 3:55 PM by wooffi1 RSS
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Berry with an \ Level 1 Level 1 (0 points)
Currently Being Moderated
Jun 22, 2010 8:59 PM
• 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


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.


• 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 ??

( Grumbling bout my Mac)
Which one of twelve??, Mac OS X (10.5.6), ever hear Newton?!! ;-) One of those, too!
  • Barry Hemphill Level 7 Level 7 (33,115 points)
    Currently Being Moderated
    Jun 23, 2010 4:38 AM (in response to Berry with an \"A\")
    Hi Berry with an "A" (that is a riot, I have the same problem):

    You have been most thorough in your post and have documented the problem well.

    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 completely agree with your assessment and course of action. Even if others have experienced similar problems, my reaction would be to suspect hardware as a cause. Be sure to have your complete documentation at hand when you contact Applecare.


    (with an "A")
    ´ú┐iMac 20" 2.4 GHz Intel-based/2 GB, DSL, Firewire HDs, Mac OS X (10.6.4)
  • Francisco Pereira Level 1 Level 1 (25 points)
    Currently Being Moderated
    Jun 23, 2010 11:29 AM (in response to Berry with an \"A\")
    Today the same happened to me.
    Imac 2,66Mhz i5, 27', Mac OS X (10.6.4), 2TB HD, 8 Gig RAM
  • ZigZagLens Level 1 Level 1 (0 points)
    Currently Being Moderated
    Jun 24, 2010 2:37 PM (in response to Berry with an \"A\")
    I had this happen with mine, just a couple weeks after I bought it. Same config - 2.8GHz, i7, 8GB RAM, 1TB.

    There are several threads about it, suspiciously dating back to the SMC firmware update issued in April. You might want to see this one: and the threads referred to therein.

    You'll also notice in those threads that users with the complaint also have 27" i7s with 8GB RAM.

    Anyway, finally one morning it wouldn't wake from sleep - nor start up (except occasionally showing the gray screen then shutting off again) and I brought it back to Apple.

    They had it for several days. Initially when I called to check on it, they said they couldn't replicate the issue and it was working fine (even though the Genius taking it in personally witnessed it), and said I should come pick it up.

    I refused, and asked to speak with the guy who took it in. He said they "reseated the RAM" so it was probably the RAM. I wasn't buying that, so I pushed him to dig deeper. Eventually they replaced the power supply and the optical cable (at my insistence/urging - I don't think this was done for any particular reason other than to take a blind swing at possible causes.)

    Anyway, I've had it back probably six or eight weeks, and it hasn't happened since - BUT - I also haven't applied the SMC firmware update since getting it back - despite Software Update urging me to at least daily.

    If I had the courage, I'd apply the SMC firmware update again and see if the problem returns. But I don't want to be without the iMac for another week or longer - this is my primary machine I use at work.
    Macbook Pro, Mac Pro, iPhone 3G, Mac OS X (10.6.4), Mac Pro, Macbook Pro, iPhone, etc.
  • elmac Level 5 Level 5 (4,230 points)
    Currently Being Moderated
    Jun 24, 2010 2:51 PM (in response to Berry with an \"A\")
    Hi, it will be interesting to see what results you get - Knowing the System!
    In my experience Apple never acknowledge an Issue (unless it is real serious)
    I used to work with an Apple Service Rep -> 3 Macs on his w/bench -> ALL with the same issue"'
    he told a Mac user @ the Service desk with the """Same Issue"" ""I have NEVER encountered That Issue...
    He was straight faced..Me I walked away.. In all honesty I have never in 10years known Apple to walk away from an Issue when Corp/Customer service became involved...My experience with my Laptops
    was gratifying (Two 1yr olds replaced with latest 2010 models)
    I feel your issue is down to a Power/Ballast unit within the PowerPack...L
    4 Macs - 2 iPhones - 7iPods - 3Leica's - 2Nikon's, Mac OS X (10.6.4), Use em all" - Luv em All" - Need em all!!
  • tjtrapp Calculating status...
    Currently Being Moderated
    Jun 27, 2010 10:09 AM (in response to Berry with an \"A\")

    I'm having a similar random shut down problem. If I power on the computer, it just turns off. It's currently powering off before I can login but earlier today it was powering off well after I had logged in and began to work.

    After it shuts down, the only way I can power it back on is to unplug it for a few minutes... but the cycle continues. It powers on and before the login screen appears it powers off.

    At first I thought it may be due to the temp, so I let it warm up for a bit but that didn't seem to help b/c the problem continues.

    I tried plugging it into different power sources: a surge protector, a wall outlet, a different wall outlet. None of the changes allowed the computer to work normally.

    I would like to try a different power cord, but need to go get one from the store so I might as well just bring the box w me :/

    Any idea to prevent a trip to the store would be super.

    Thanks in advance.
    iMac i5, Mac OS X (10.6.4), ram
  • Chris Beall Level 1 Level 1 (30 points)
    Currently Being Moderated
    Jun 30, 2010 10:51 AM (in response to Berry with an \"A\")

    Based on your previous posts, I'm going to try to summarize your problem to make sure my understanding of it is correct. Please correct any errors.

    27" 2.8 GHz Intel Core i7 / 8gig / 1TB
    All software and firmware up to date.
    3 external drives: 1-320 gig 800fw / 1-TB USB 2.0 / 1-500gig USB 2.0

    Primary symptom:
    System shuts down without warning. Frequency: twice, in one week.

    Secondary symptoms:
    Fans "kick WAY too much sometimes". (from a post in another thread).
    Processing slowdown (slowed response, beach balls).
    System very hot to touch at top of enclosure.

    Problem did not appear until after recent SMC firmware update.
    Ambient temp 64-77 F.
    "All components" temp ~105-140 F.
    Hardware tests pass without error.

    Corrective actions tried and results:
    28 Jun 2010 - SMC reset (no failures since)

    What is your current SMC Version?
    Have you noticed high fan speeds (noise) since applying the most recent SMC firmware update?
    What, if any, software do you have installed that displays system temperatures and fan speeds?
    What, if any, software do you have installed that controls fan speeds?

    Chris Beall
    21.5" iMac 10,1 3.33GHz 8Gb SMC 1.52f9, Mac OS X (10.6.4), Bluetooth keyboard and Magic Mouse
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