sgiurin

Q: iMac suddenly shutdown with previous cause -128

Dear all,

 

in the last days I'm facing a problem with my iMac.

 

It randomly shutdown, sometimes restarting by itself, sometimes having to disconnect the electricity and wait a couple of minutes to restart.

 

I upgraded my iMac several months ago with an external SSD connected via Thunderbolt port, and added extra RAM, but everything works perfectly since months.

 

I've tried reinstalling OS X, but nothing changed.

I've measured the temperature using emcfancontrol, but nothing special (max 60° Centigrade).

 

I've tried running Apple Hardware Test, holding "D" key while iMac boots, but AHT doesn't start, I just have the recovery windows where I can run Disk Utility, reinstall OS X etc, but no Hardware test.

 

The only message I found on the console after a sudden restart is "Previous shutdown cause: -128". Anyone knows what does it means ?

And do you have any idea on how can I run the Hardware test ?

 

Many thanks in advance

 

iMac Mid 2011

iMac, Mac OS X (10.7.5), OS X installed on external SSD

Posted on Dec 6, 2015 12:53 AM

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Q: iMac suddenly shutdown with previous cause -128

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  • by Rudegar,

    Rudegar Rudegar Dec 6, 2015 2:15 AM in response to sgiurin
    Level 7 (28,566 points)
    Apple TV
    Dec 6, 2015 2:15 AM in response to sgiurin
  • by Linc Davis,

    Linc Davis Linc Davis Dec 6, 2015 8:26 AM in response to sgiurin
    Level 10 (207,963 points)
    Applications
    Dec 6, 2015 8:26 AM in response to sgiurin

    A negative shutdown code may indicate a hardware problem. The precise meaning of the codes is not publicly documented.

    If you haven't already done so, you can try resetting the System Management Controller. Otherwise, or if the reset has no effect, see below.

    Make a "Genius" appointment at an Apple Store, or go to another authorized service provider. You may have to leave the machine there for several days.

    Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional—ask if you need guidance.

    If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

    Keeping your confidential data secure during hardware repair

    Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.

    *An SSD doesn't need to be zeroed.

  • by sgiurin,

    sgiurin sgiurin Dec 6, 2015 11:41 AM in response to Linc Davis
    Level 1 (0 points)
    Dec 6, 2015 11:41 AM in response to Linc Davis

    Thanks. I don't know how to reset SM. At the moment I've tried disintalling the additional 8 GB RAM.

    Now I'm waiting to see if the problem come back.

    I'm still wondering why Apple Hardware Test doesn't work.

    Holding key "D" while booting has no effect; holding CMD+R it says is connecting to the internet and it can take some minutes, but after 1 hour nothing happened.

  • by sgiurin,

    sgiurin sgiurin Dec 6, 2015 11:45 AM in response to Rudegar
    Level 1 (0 points)
    Dec 6, 2015 11:45 AM in response to Rudegar

    Ciao Rudegar,

     

    yes I've done. The funny thing was that I've tried exactly copying and past the error, and I was not able to find any -128.

    I realized only after a while that on Google -128 means "exclude results -128"

     

    Many discussions refer to RAM problem, so I'm trying to work after removing 8 GB RAM.

     

    Thanks

  • by Linc Davis,

    Linc Davis Linc Davis Dec 6, 2015 11:55 AM in response to sgiurin
    Level 10 (207,963 points)
    Applications
    Dec 6, 2015 11:55 AM in response to sgiurin

    I don't know how to reset SM.

    The instructions are linked to my last comment.

  • by sgiurin,

    sgiurin sgiurin Dec 6, 2015 1:13 PM in response to sgiurin
    Level 1 (0 points)
    Dec 6, 2015 1:13 PM in response to sgiurin

    IT crashed again now, even without the additional RAM.

    I've installed OS X also in a partition on the internal HD and restarted from there, but the apple hardwRe test still doesn't start.

    I!m going to follow your suggestion Davis.

  • by sgiurin,

    sgiurin sgiurin Dec 7, 2015 3:44 AM in response to sgiurin
    Level 1 (0 points)
    Dec 7, 2015 3:44 AM in response to sgiurin

    Nothing works

    The only thing I notice is that the system crash when I'm using different games (intensive graphics), so I'm suspecting GPU or Graphic Card issue ...

    I'm going to have a Genius appointment.

  • by Linc Davis,

    Linc Davis Linc Davis Dec 7, 2015 6:20 AM in response to sgiurin
    Level 10 (207,963 points)
    Applications
    Dec 7, 2015 6:20 AM in response to sgiurin
  • by sgiurin,

    sgiurin sgiurin Dec 25, 2015 12:43 AM in response to sgiurin
    Level 1 (0 points)
    Dec 25, 2015 12:43 AM in response to sgiurin

    Update

     

    I went to the Apple Store to have a repair. They kept for 8 days the iMac under stress test. The problem showed just 1 time. After that they reset the 'power supply' removing electricity and restarting holding the power on key, then it never happened again.

    They gave me back the iMac hoping now it works fine. The good news is that they did it all for free.

    After I went back at home, in two hours the problem happened again. In the next few hours it happened 3 times.

    It seems that after it happens, it start happening frequently. When I restart removing electricity, waiting 30 secs, start holding the power key, I have a 'safe' period before it rehappens.

     

    I called back the Apple Support, they were very sorry, now they plan to substitute the Graphic Card.

    Dec 29 I'll bring them the iMac for the repair. At this point in time I really have no clue it this can solve the issue.

     

    @Linc  Thanks, I saw that article, but it's related to 27 inch iMac, mine is 21 inch and seems not to be in

  • by Yukka21,

    Yukka21 Yukka21 Jan 15, 2016 1:26 PM in response to sgiurin
    Level 1 (0 points)
    Jan 15, 2016 1:26 PM in response to sgiurin

    Any new updates? I am curious because I have the same problem.

  • by sgiurin,

    sgiurin sgiurin Jan 16, 2016 3:04 AM in response to Yukka21
    Level 1 (0 points)
    Jan 16, 2016 3:04 AM in response to Yukka21

    The story ended.

     

    They replaced the Graphic Card, but the problem was not solved.

     

    Next action was to replace the Mother Board. More than 600€. Their suggestion was to not go on with the repair, due to the unbalance between the coat of repairing against the value of the iMac. And I agreed.

     

    I saved my hard disk and the ram, that's it.

     

    The only good news is that they did all for free.

  • by Yukka21,

    Yukka21 Yukka21 Jan 16, 2016 8:36 AM in response to sgiurin
    Level 1 (0 points)
    Jan 16, 2016 8:36 AM in response to sgiurin

    Sorry to hear that. I am still trying to figure something out. Until then, I will have to run in Safe Mode.

  • by Eddie Jasmine,

    Eddie Jasmine Eddie Jasmine Feb 5, 2016 6:20 AM in response to Yukka21
    Level 1 (63 points)
    Feb 5, 2016 6:20 AM in response to Yukka21

    Hi Yukka.

     

    I had the same problem with my iMac 9,1 early 2009 with Nvidia geforce GT 130 512 MB.  Even though Apple doesn't publicly post what the previous shutdown code means, I'm positive that previous shutdown cause -128 is a failure of the graphics system.  Now most people think it's the graphics card alone, but they forget about the pci-e slot.  The first go around, I reflowed my graphics card in the oven.  Go to this thread and the last post for the explanation of what I did Re: Early iMac 2009 shuts down unexpectedly Yosemite only

     

    The fix lasted for about a month and a half before the -128 curse started reappearing sporadically.  So I reflowed the card again at a higher temp and longer time (415 F for 15 minutes), having positioned the card lower to the tray (about .5 cm clearance between card and foiled tray) to make sure the underside was getting good heat.  I also cleaned the card thoroughly after the bake and cooling down...then reapplied new thermal paste (the pads where still good).

     

    The only difference this time was that I inspected the inside of the pci-e slot.  I began scraping the connectors with a narrow plastic slice from an expired credit card (if I you have a very small, wire brush, that would be better).  A lot of gunk started coming up.  So I thoroughly cleaned the slot, scraping then going over it with a cotton swab with alcohol.  I then reinstalled the card and I haven't had a problem since.  It makes sense because the pci-e slot supplies power and if there is gunk on the connectors, that will interfere with certain power functions.

     

    So what's the upshot?  It could be a problem with both the graphics card AND the logic board (pci-e slot)! 

     

    I can tell you that your problem will not get better, only worse, without intervention.  Operating your computer in Safe Mode is probably not cutting it for you.  Now, there are risks involved in reflowing your graphics card and it could ruin it, but if you want to get your computer back, fully-functional, I would recommend the procedure.