Intel iMac Suddenly Shuts Down or Kernel Panics

Discussion in 'Apple' started by Old_CSMAer, Nov 6, 2008.

  1. Old_CSMAer

    Old_CSMAer Guest

    Posting in comp.sys.mac.system because the Apple boys told my son in law
    there is no hardware issue.

    Symptoms: Late model Intel iMac (latest edition of Leopard) just shuts
    down or panics for no reason. They could be playing a game, browsing
    the web, or word processing.

    I suggested a reformat of the drive, overwriting zeroes, then
    re-installing just Leopard, no apps. Then wait and see. Told them not
    to connect any USB devices...even disconnect their MS keyboard and
    mouse, and reattach the Apple devices. Told them to add one app a day
    and slowly add one app or usb device at a time until something happens.

    Any other suggestions?
     
    Old_CSMAer, Nov 6, 2008
    #1
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  2. Yep. When MacOS X starts crashing like that "out of the blue" is almost
    ALWAYS hardware. Either RAM went bad but not bad enough to fail
    diagnostics or there's something loose or a loose-sodered connection on
    the mobo. Or maybe even the dreaded "tin whisker":

    http://dataweek.co.za/news.aspx?pklNewsId=15032&pklCategoryId=49
    http://www.srgclub.org/Wisker_2.html
    http://nepp.nasa.gov/WHISKER/

    In any case, start documenting dates, times, peripherals, and activities
    when it's crashing. Keep a notebook by the system and write it all
    down. If you can take the machine into Apple while it's still under
    warrantee with evidence that there is something wrong, you have a better
    chance of getting someone to fix it.
     
    Michael Vilain, Nov 6, 2008
    #2
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  3. Sounds like a hardware issue to me, but reformatting and re-installing
    everything should make that certain. If it acts up again, have you got
    another place authorized to service Macs in the area?

    Before you take it in again you should probably eliminate bad RAM.
     
    Steven Fisher, Nov 6, 2008
    #3
  4. Old_CSMAer

    Old_CSMAer Guest

    I thought of RAM too, but the service center said they checked that
    first. I'm thinking a USB device with a short.
     
    Old_CSMAer, Nov 7, 2008
    #4
  5. Old_CSMAer

    J.J. O'Shea Guest

    If you're suddenly having KPs for no known good reason, I would suspect two
    things first:

    1 bad RAM

    2 a bad USB peripheral

    In my experience 90+% of KPs are caused by one of the above.

    I'd remove all USB peripherals except the mouse and keyboard and see if the
    problem goes away. If it does, add devices back in one at a time. Note that
    you might have to run without USB devices for a day or so to ensure that the
    system is actually working properly, and that it would be a good idea to add
    each device in one at a time and to spend a day or so running with them to
    eliminate them as a possible cause. If you have a spare keyboard and mouse,
    try them.

    If the USB devices pass, check the RAM. This may require pulling one or more
    RAM sticks, depending on which model Mac you have. Be careful that you don't
    damage the RAM sticks when removing them, introducing problems where there
    weren't any in the first place. Observe anti-static safety rules.
     
    J.J. O'Shea, Nov 7, 2008
    #5
  6. Been there. Done that. That was actually on one of my Windows boxes, but
    the principle is the same.

    In a way, it did "solve" my problem. I was trying to determine whether
    or not the RAM was bad. I don't know whether or not it originally was
    bad, but after I zapped it, there was no more uncertainty left. It was
    then trivial to see that the RAM was bad. :-(
     
    Richard Maine, Nov 7, 2008
    #6
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