System doesn't power down completely

Discussion in 'DIY Computers' started by Jonathan Eales, Mar 22, 2005.

  1. I have a generic Pentium 3 800MHz, 256Mb, MSI 6154VA motherboard with
    Windows XP SP2.

    When I shutdown the computer it powers off but leaves the CPU fan running
    and the front panel LEDs are dimmed but still on. Power cycling the switch
    at the back on the power supply turns the system off completely.

    Is this some kind of standby or soft power off mode? I've reset the BIOS
    but it still happens.

    Jonathan Eales, Mar 22, 2005
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  2. Jonathan Eales

    nl Guest

    When you say, 'shut it down', how are you shutting it down? Through
    the Start button dialogue? Or via the on/off button at the front of
    the machine? The on/off button can be set to shut, down, enter
    standby, or do nothing. if you are using that button, sounds like it
    might be setting the PC to standby. Look under control panel/power
    for the options.

    OTOH, if you are using the Start button dialogue and choosing 'turn
    off' and it is behaving as you describe then I am boogered if I kno.
    You might want to check power settings in the BIOS?


    (and before any bright spark suggests that 'only MS could shut a
    machine down using the "start" key', may I point out that that's
    exactly what you do with a car.)
    nl, Mar 22, 2005
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  3. Jonathan Eales

    Alex Fraser Guest

    I'd say a voltmeter is the next step after that - to check the PSU-on signal
    and the power outputs.
    Well, the action on Windows is to _start_ shutting down, so you can twist it
    to be logical :). But I'm not convinced by your analogy.

    Alex Fraser, Mar 22, 2005
  4. There is usually a BIOS option for what the front panel power button
    does - one option is 'Standby', which may well leave the CPU fan
    running. One option should be 'off' which shouldn't leave anything
    running. Read the BIOS manual (or options) carefully.
    GSV Three Minds in a Can, Mar 22, 2005
  5. Jonathan Eales

    Rob Morley Guest

    I had a similar thing with a machine that had an internal USB hub -
    if I connected the hub to the PSU it fed power back into the board
    and the graphics card fan continued running, but not when the hub was
    running self-powered.
    Rob Morley, Mar 22, 2005
  6. Thanks Guys,

    Yes, I am using the Shutdown command via Windows, not just hitting the power
    button. There is no powered USB hub in the box.

    I noticed that though the motherboard specification and BIOS states that it
    is ACPI/APM compatible, Windows XP gives a 'Standard PC' as Computer
    properties in Device Manager. I've reset the BIOS and reinstalled Windows
    XP and it stays the same.

    APM is set on.

    Any further help would be appreciated.


    The motherboard manual states:
    Power Management

    Disable Global Power Management will be disabled.

    User Define Users can configure their own power management.

    Min Saving Pre-defined timer values are used such that all timers are in
    their MAX value.

    Max Saving Pre-defined timer values are used such that all timers are in
    their MIN value.

    PM Control by APM

    No System BIOS will ignore APM when power managing the system.

    Yes System BIOS will wait for APM’s prompt before it enter any PM mode

    Note :Enable this for O.S. with APM like Windows® 95, Windows® NT, etc.

    Video Off Option

    When Enabled, this feature allows the VGA adapter to operate in a power
    saving mode.

    Always On Monitor will remain on during power saving modes.

    Suspend --> Off Monitor blanked when the systems enters the Suspend mode.

    Suspend/Standby --> Off Monitor blanked when the system enters either
    Suspend or Standby modes.

    All Modes --> Off Monitor blanked when the system enters any power saving

    Video Off Method

    Blank Screen The system BIOS will only blank off the screen when disabling

    V/H SYN C+Blank In addition to (1), BIOS will also turn off the V-SYNC &
    H-SYNC signals from VGA card to monitor.

    DPMS This function is enabled only for VGA card supporting DPMS.

    Note: Green monitors detect the V/H SYNC signals to turn off its electron


    Name the interrrupt request (IRQ) line assigned to the modem (if any) on
    your system. Activity of the selected IRQ always awakens the system. The
    settings are NA, 3, 4, 5, 7, 9, 10, or 11.

    Reserve IRQ 9

    This item is reserved for WindowsÒ 98 ACPI mode. Choose yes, if you use
    WindowsÒ 98 ACPI mode. Otherwise, set to no.

    Soft-Off by PWRBTN

    Pressing the power button for more than 4 seconds forces the system to enter
    the Soft-Off state when the system has “hung.” The settings are Delay 4 Sec,

    PM Timers

    The following four modes are Green PC power saving functions which are only
    user configurable when User Defined Power Management has been selected.

    HDD Power Down

    When Enabled and after the set time of system inactivity, the hard disk
    drive will be powered down while all other devices remain active.

    Doze Mode

    When Enabled and after the set time of system inactivity, the CPU clock will
    run at slower speed while all other devices still operate at full speed. The
    settings are Disabled, 10sec, 20sec, 30sec, 40sec, 1min, 2min, 4min, 6min,

    Suspend Mode

    When Enabled and after the set time of system inactivity, all devices except
    the CPU will be shut off. The settings are Disabled, 10min, 20min, 30min,
    40min, 1hour.

    PM Events

    PM events are I/O events whose occurence can prevent the system from
    entering a power saving mode or can awaken the system from such a mode. In
    effect, the system remains alert for anything which occurs to a device which
    is conficured as On, even when the system is in a power down mode.


    When Enabled, you can set the LAN to awaken the system.

    LPT & COM

    When On of LPT & COM, any activity from one of the listed system peripheral
    devices or IRQs wakes up the system

    HDD & FDD

    When On of LPT & COM, any activity from one of the listed system peripheral
    devices or IRQs wakes up the system

    Wake Up On LAN

    To use this function, you need a LAN add-on card which support power on
    functions. It should also support the wake-up on LAN jumper (JWOL1).

    Enabled Wake up on LAN supported.

    Disabled Wake up on LAN not supported.

    Modem Ring Resume

    An input signal on the serial Ring Indicator (RI) line (in other words, an
    incoming call on the modem) awakens the system from a soft off state.

    RTC Alarm Resume

    When Enabled, you can set the date and time at which the RTC (real-time
    clock) alarm awakend the system from Suspend mode.


    The following is a list of IRQ’s, Interrupt ReQuests, which can be exempted
    much as the COM ports and LPT ports above can. When an I/O device wants to
    gain the attention of the operating system, it signa;s this by causing an
    IRQ to occur. When the operating system is ready to respond to the request,
    it interrupts itseld and performs the service.

    When set On, activity wil neither prevent the system from going into a power
    management mode nor awaken it.

    l IRQ3 (COM 2)

    l IRQ4 (COM 1)

    l IRQ5 (LPT 2)

    l IRQ6 (Floppy Disk)

    l IRQ7 (LPT 1)

    l IRQ8 (RTC Alarm)

    l IRQ9 (IRQ2 Redir)

    l IRQ10 (Reserved)

    l IRQ11 (Reserved)

    l IRQ12 (PS / 2 Mouse)

    l IRQ13 (Coprocessor)

    l IRQ14 (Hard Disk)

    l IRQ15 (Reserved)
    Jonathan Eales, Mar 22, 2005
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