booting into BIOS setup

Discussion in 'Asus' started by Linea Recta, Apr 6, 2004.

  1. Linea Recta

    Linea Recta Guest

    Sometimes when I switch the computer on, it boots directly into the BIOS
    setup. (luckily nothing gets changed, because I use passwords).
    Since I don't want to enter the setup, I press the reset button, and then I
    can boot the OS normally.
    What can be wrong?
    I use NAV (updated each day).


    os: Windows 2000 Pro SP4 - mobo: Asus P4B266 - cpu: Intel P4 1,6 GHz. - mem:
    512 MB. - video: Matrox Marvel G450eTV 32 MB. (AGP) - monitor: iiyama Vision
    Master 1401 - sound: SB Audigy 1394 (PCI) - hd: 2 X Maxtor 60 GB. -
    DVD/CD-ROM: Toshiba DVD-ROM SD-M1712 - DVD+RW/+R: AOpen DVRW2412Pro -
    modems: ADSL: Alcatel speedtouch 330 (USB) - analog: Dynalink Lucent Win
    Modem 56k6 (PCI) - printers: HP DeskJet 720C (parallel) & HP LaserJet IIP
    Plus (parallel) - keyb: PS/2 MS Internet Keyboard - mouse: Logitech Pilot
    Wheel Mouse Optical (USB) - webcam: Logitech QuickCam Zoom (USB) -
    removables: Maxtor One Touch 120 GB (USB) - Iomega ZipDrive 100 (parallel)
    Linea Recta, Apr 6, 2004
    1. Advertisements

  2. Linea Recta

    Rob Hemmings Guest

    If the 3v lithium mobo battery is running down, the board may be
    detecting a CMOS (BIOS settings stored here) checksum error
    and taking you straight into the BIOS. If you can measure the
    battery voltage, make sure it's above 3v. If you can't, try a new
    Rob Hemmings, Apr 6, 2004
    1. Advertisements

  3. Linea Recta

    Linea Recta Guest

    All right, I'll check it out. (I wonder when they're going to invent a
    battery which gets recharged by the system power supply...)


    |\ /|
    | \/ |@rk
    Linea Recta, Apr 6, 2004
  4. Linea Recta

    Paul Guest

    A coin cell would blow up if you charged it. A rechargable battery
    would self discharge and not give you the same continuous service
    life that the coin cell does. It is really a good design, except
    when the battery is dead to begin with. The only thing that would
    be better, is using a larger cell, and that would be more
    expensive to replace.

    You might want to check your fan speed. On my computer, I have a
    PS fan connected to a fan header, and on cold boot, the PS fan
    runs so slow, the RPMs are less than the threshold in the power
    monitor. The BIOS prompts me to fix it, but by the time I enter
    the BIOS, the PS has warmed up enough that the fan speed is
    then above the threshold, and there is nothing to fix. So,
    check out your fan speed as a root cause. It could be the
    BIOS has an option to [Ignore] the fan in question.

    Paul, Apr 6, 2004
  5. Linea Recta

    Linea Recta Guest

    I suppose the battery is only to keep time/date clock running? Are the other
    settings kept in flash memory?


    |\ /|
    | \/ |@rk
    Linea Recta, Apr 7, 2004
  6. Linea Recta

    Paul Guest

    The Southbridge has two areas of silicon in it. One is tiny and
    contains 256 locations of SRAM (called the CMOS ram) plus a real
    time clock. There is a 32KHz crystal outside the Southbridge that
    oscillates just like in a wrist watch, and it feeds the RTC.
    So, time and settings are contained in that part of the Southbridge.
    (That part of the chip is sometimes referred to as the "CMOS well",
    due to the isolation techniques used to separate that part of
    the chip from the rest of it.)

    From the ICH5 datasheet:

    "Real-Time Clock
    ‹ 256-byte battery-backed CMOS RAM
    ‹ Integrated oscillator components
    ‹ Lower Power DC/DC Converter implementation"

    The Southbridge has two power supplies. The majority of the Southbridge
    runs from the main power outputs of the PS. The tiny chunk of
    silicon containing the CMOS ram and RTC is powered by the standby
    supply, and it consists of a diode-ORed combination of +5VSB (reduced
    to 3V) and the 3V coin cell. When the computer power cord is unplugged,
    the coin cell is the sole source of power for the Southbridge
    standby. The dual diode prevents the 3V coin cell from being
    charged by the +5VSB derived source.

    When the computer is plugged in and switch on (on the back) but you
    haven't pushed the button on the front, the +5VSB is operating and
    the green LED on the motherboard will be lit. At this time, the
    dual diode cuts off the coin cell, so no juice is drawn from the
    coin cell. So, really, the only time the coin cell is draining is
    when the switch on the back of the computer is in the OFF position
    or the cord is pulled.

    Paul, Apr 7, 2004
  7. Linea Recta

    Linea Recta Guest

    Linea Recta, Apr 8, 2004
  8. Linea Recta

    Paul Guest

    Paul, Apr 8, 2004
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.