P5P800 Won't POST

Discussion in 'Asus' started by Fred Mayfield, Jan 21, 2005.

  1. Among other things, I just bought new ATX case, P5P800 w/P4 520 mother
    board, 2 512MB DDRs, ATI Radeon 9250, Matrox Serial ATA HDD, floppy, DVD,
    etc. and it won't POST. The CPU fan comes on and a green LED on the
    motherboard lights up to show power is applied. Only thing that struck me as
    unusual is that the 350W power supply only has 20 pins with the plug on the
    MB has 24. The way the connector is keyed, it only fits onto the connector
    one way .... buttttttt, it don't seem right.

    Anybody know anything about the connector differences? I logged a support
    request on the Asus web site ..... buttttttt, who knows, maybe they'll

    Also, I don't have any experience with a SATA HDD. Do they partition and
    format in a manner similar to an IDE drive or are there secrets to make it


    Fred Mayfield, Jan 21, 2005
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  2. suggest you check something like Tom's hardware. There is apparently a new
    power supply design coming out and the P4 power supplies are different I
    For SATA drives XP treats it as SCSI. you need the drivers.
    notritenoteri, Jan 21, 2005
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  3. Have you made sure that the CPU fan is firmly connected? I had similar
    problems with this board. The new mounting method sucks in my opinion.
    There is no positive indication that it is properly mounted. It works
    fine with a 20 pin connector but I upgraded to one with the 24 pin
    connector to see if it made any difference.
    Michael W. Ryder, Jan 22, 2005
  4. Fred Mayfield

    Homer Guest

    Homer, Jan 22, 2005
  5. Fred Mayfield

    Paul Guest

    Is the 2x2 ATX12V power connector in the upper left hand
    corner connected ?

    The 24 pin connector has four extra pins (+3.3, +5, +12, GND).
    These were added for PCI Express powering.

    Your board doesn't have PCI Express, as far as I know.
    It is an AGP board.

    This is the power information from the AGP 3.0 spec, for
    power flowing through the AGP slot connector:

    Symbol Parameter Condition Min Max Notes
    Vddq1.5 I/O Supply Voltage IMAX=2.0A 1.425 1.575V 1, 2
    VCC3.3 3.3V Power Supply IMAX=6.0A 3.15 3.45V
    3.3VAUX 3.3V Auxiliary IMAX=0.375A 3.15 3.45V
    VCC5 5V Power Supply IMAX=2.0A 4.75 5.25V
    VCC12 12V Power Supply IMAX=1.0A 11.4 12.6V

    The +12V feeding the AGP slot is limited to 1 amp consumption
    through the slot connector. If any additional +12V is
    required, a separate connector on the AGP card takes care
    of it. Roughly translated, this means the additional +12V pin
    on the 24 pin power connector, will not be of much use.
    For the P5P800 only, that means a 20 pin ATX power connector
    should be adequate to power the board. The board is, after
    all, a P4P800 with a LGA775 processor socket stuck on it.
    And the P4P800 uses a 20 pin ATX power connector.

    Other members of the P5xxx family of boards, are PCI Express
    based. More power can be drawn through a PCI Express slot,
    but how much more I cannot tell you, as finding that kind of
    detail without buying a spec is hard to do.

    Paul, Jan 22, 2005
  6. Fred Mayfield

    Homer Guest

    The power requirements in the manual states that you need a 24 pin ATX
    power supply and a 4 pin 12volt plug. ATX version 2, on page xii in the
    manual. Give it a look.

    Homer, Jan 22, 2005
  7. Fred Mayfield

    Stephen Macy Guest

    Stephen Macy, Jan 22, 2005
  8. Page 2-28 says that you Can use a 20 pin connector if it can provide at
    least 8A on the +12V lead and at least 1A on the +5V standby lead. I
    have this board and it booted fine with a Zalman 400 power supply with
    the 20 pin connector.
    Michael W. Ryder, Jan 24, 2005
  9. Fred Mayfield

    Bill Guest

    Depending on your cpu speed the P4 can use upto 100 W. PCPower and
    Cooling suggested a 470 W which is PCIx ready and has the 24 pin
    connector. I was tempted to try my old 350 W too but after reading the
    requirements above gave up.
    Bill, Jan 29, 2005
  10. Fred Mayfield

    Vince Guest

    A good quality ATX (20pin) power supply min. 400-450W will still work
    on this board due to not having PCIe on this board.

    However a 24 pin eATX V2 will be needed on some 775 boards.
    Vince, Feb 4, 2005
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