Computer exits sleep mode during static discharge

Discussion in 'PC Hardware' started by Yousuf Khan, Dec 1, 2014.

  1. Yousuf Khan

    Yousuf Khan Guest

    Okay, it's winter time here, relative humidity is low, so there's a lot
    of static build-up on your clothes. Now, I've noticed that during those
    static discharges, I can hear the computer immediately exits sleep mode.
    Even if the discharge didn't happen anywhere near the computer, it may
    have happened a room or two over, but you still hear the computer
    powering up. Is it possible that a discharge could come *up* through the
    grounding wires?

    Yousuf Khan
    Yousuf Khan, Dec 1, 2014
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  2. Yousuf Khan

    Flasherly Guest

    Doubt it. Combination of predominately Windows' software and some
    interaction given leeway for slight changes hardware manifests over
    deviance from any sot of exacting precision programming them may, more
    or less, expect. I'd expect we'd be programming them for sunspots as
    well as grounding were it otherwise. You've a mouse/keyboard "human
    device," some contingency within related hibernation devices that's
    physically changed, faulting or out of specs, since initially
    installed properly, if not a greater likelihood for software migrating
    away from that original definition.

    Ghosts in the Shell. Binary backups. A reinstall of Windows. Various
    ways to interpret its humaneness, I suppose.
    Flasherly, Dec 1, 2014
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  3. Yousuf Khan

    Paul Guest

    Go to Device Manager and check the NIC properties.
    There can be multiple Wake On Lan items to select
    from. Make sure anything related to "carrier" is
    disabled, as a static discharge may cause enough of
    a "blurp" on the NIC wire, to trigger a rise from sleep.

    I would start by ensuring that *all* Wake On LAN is
    disabled. You can undo the setting later if you want.

    The second step would be to carefully examine all
    cables leaving the computer. Do you run a USB transfer
    cable, that runs from computer to computer ? That
    ends up connecting the grounds of the two computers
    together, which is only recommended if the computers
    are running off the same power strip.

    Try to ensure the I/O wiring isn't contributing
    to the problem.

    We had a problem like this at work, and the root
    cause in our case, was the reset wire inside the
    computer case, acted as an "antenna". It would
    cause the computer to reset, even during a static
    event 20 feet from the computer. Since your return
    from sleep, takes you back to Windows again, then it
    probably isn't a reset, but a Wake event instead.
    And I'm thinking the NIC is set to "wake on carrier
    change" or something similar.

    Paul, Dec 1, 2014
  4. If you have not already done so test the outlet and or outlet strip that
    is servicing the PC to verify that it is wired correctly as well as
    properly grounded.

    It would not be the first 3-prong replacement outlet that was stuck into
    an outlet box that was wired to only accept the ungrounded older 2-prong
    GlowingBlueMist, Dec 1, 2014
  5. Yousuf Khan

    Yousuf Khan Guest

    That does sound very plausible, but I do need to make use of the wake on
    lan feature here, so I'm not going to disable it. But it does give me a
    good theory explain it. It's not so much a problem as a curiosity.

    Yousuf Khan
    Yousuf Khan, Dec 1, 2014
  6. Yousuf Khan

    Yousuf Khan Guest

    Another good theory to check into, this is possible. The building I live
    in was built back in 1976. Electrical wiring has hardly been changed since.

    Yousuf Khan
    Yousuf Khan, Dec 1, 2014
  7. Yousuf Khan

    Paul Guest

    Yes, but WOL has as many as four "patterns".

    Wake on Carrier is the stupid one.

    Wake on specific pattern (the traditional WOL)
    will still work, without being triggered by static

    It's the Wake on Carrier change that causes the problem,
    because virtually anything can trigger it. And since
    Ethernet wiring "floats" and there is no DC ground present,
    there is a potential for the wiring to work as an antenna.
    Not an efficient antenna, but the potential is still there.

    I've placed a scope on Ethernet wiring, as part of my last
    job in the lab. And you can see tens of volts of potential
    (common mode) riding on an Ethernet cable. The transformer at
    the end of the line, removed the common mode stuff. The input
    looking at the other side of the transformer, should remove
    a little bit of common mode. It would be things like parasitic
    capacitance in the transformer, which might couple through the
    static discharge. And disabling the Wake on Carrier, and using
    some other pattern, will make the "key" to unlock sleep, that
    much more complicated.

    Paul, Dec 1, 2014
  8. Yousuf Khan

    Paul Guest

    They make outlet testers.

    Those are crude devices, but they're also self contained
    and there are no wires to screw with. Such a device is
    good for detecting an open circuit on Safety Ground.

    Paul, Dec 1, 2014
  9. Yousuf Khan

    Yousuf Khan Guest

    Okay, I might test it out, you got me curious. And I do have one 10m
    (30ft) cable on this LAN, which might be the one acting as an antenna.

    Yousuf Khan
    Yousuf Khan, Dec 2, 2014
  10. Yousuf Khan

    Yousuf Khan Guest

    Alright, I turned on the feature called "Only allow a magic packet to
    wake the computer". So far so good, seems to be keeping it from waking
    up with a static discharge.

    Yousuf Khan
    Yousuf Khan, Dec 5, 2014
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