Asus P4P800 does not boot

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  • behrk
    Member
    • Nov 2007
    • 14
    #1

    Asus P4P800 does not boot

    I have an ASUS P4P800 motherboard which does not boot. I looked at the capacitors.
    I do not see any bad one.

    When I turn on the power, all fans turn on. Mouse and keyboard lights come on.
    After a few seconds later, motherboard loses power. Mouse and keyboard lights
    start to flicker, fans lose speed. As if something is short circuited.

    I elevated the motherboard to see to see anything short circuited. That did not help.

    I tried 4 power supplies. Same thing, except one power supply did not even turn
    on the fans. LED on the motherboard was flickering.

    I replaced all the components, CPU, memory, video card.

    Did some chip go bad or is there a bad cap that I do not see?

    Thanks.
    Tags: None
    • yanz
      Badcaps Veteran
      • Nov 2004
      • 910
      #2
      Re: Asus P4P800 does not boot

      have you cleared the cmos?
      days are so short when you actually do something..

        Comment

        • Brian C
          Senior Member
          • Dec 2006
          • 156
          #3
          Re: Asus P4P800 does not boot

          Pls check the CMOS battery voltage. The button cell (CR2032) should give ~3V. I've experienced many ASUS mobos failed to boot due to flat CMOS battery.

            Comment

            • behrk
              Member
              • Nov 2007
              • 14
              #4
              Re: Asus P4P800 does not boot

              Yes, I cleared the CMOS taking the battery out and switching the bios jumper.

              I changed the battery with another one I bought a year ago. I do not know the voltage on it.
              But, another motherboard runs with both batteries.

              The weird thing is that I put the .rom bios file into a floppy and original ASUS CD which has the .rom bios file into CD drive. Motherboard tries to access them. Floppy drive light and CD drive light keep flickering. But, floppy drive does not make sound like the floppy is read.
              But, it can't read them. All the lights flash after a while. No video, no post.

                Comment

                • Big Pope
                  Approved Vendor
                  • Dec 2005
                  • 426
                  #5
                  Re: Asus P4P800 does not boot

                  There is many failed P4P800 series without any caps issues recently years in my side, always components failed. Esepcially the 4 mosfets between AGP and Ram, suggest you try to check the voltage with a multimeter first.
                  My SAMXON Capacitors Database HERE!!

                  X-CON is a new brand for SAMXON's Polymer Capacitors.

                    Comment

                    • behrk
                      Member
                      • Nov 2007
                      • 14
                      #6
                      Re: Asus P4P800 does not boot

                      I gave up on this board. Thank you for all the suggestions.

                        Comment

                        • Spacedye69
                          Badcaps Veteran
                          • Nov 2005
                          • 698
                          • US
                          #7
                          Re: Asus P4P800 does not boot

                          Originally posted by behrk
                          I gave up on this board.
                          NOOOOOOOOOO!!!!!!!

                            Comment

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