HELP......need pin or wire color codes for USB connector on P4U-LA mobo (micro-ATX)

Discussion in 'Asus' started by TJM, Jul 23, 2004.

  1. TJM

    TJM Guest

    I bought a used HP Pavilion 7955 desktop PC for $10 on eBay and the stock ASUS
    P4U-LA mobo was totally fried from a lightning strike. So I bought an Intel
    D845HV mobo to replace it, and the install went smooth except I cant figure out
    how to connect the HP's front-panel USB connector to the D845HV mobo connection.

    It's a standard 10-pin connector, but the female connection on the D845HV is
    configured different than the ASUS P4U-LA mobo. Basically, I need to get the
    pin codes off the P4U-LA female USB connector so I can properly mate the
    front-panel male connector to the D845HV female USB mobo connection.

    I have to be careful about just playing around with this connector because
    putting 5V power to the wrong pin can fry my new mobo.....correct? I tried
    looking up the P4U-LA technical manual on the ASUS site but no
    appears it was a custom micro-ATX board for this HP system.

    Please let me know where I can find the USB pin code for this mobo.
    TJM, Jul 23, 2004
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  2. TJM

    Paul Guest

    Since that is an OEM board, only HP will have the docs. It is roughly
    the same vintage as a P4B-M board, but doesn't look the same.

    Asus USB headers consist of 2x5 pins, of which nine pins are present
    and one pin is missing. There are two USB interfaces, occupying four
    pins each. The nineth pin is marked as "NC" or no connect.

    +5 D- D+ GND (No_connect)
    USBxx X X X X X <---- Top five pins goes to one
    X X X X USB interface. Last pin
    has no connection, leaving
    four pins used.

    USBxx X X X X X
    X X X X <---- Bottom has four pins and
    +5 D- D+ GND is keyed by the missing pin
    It forms the second interface.

    Now, the problem is, on an OEM board, anything is possible. Asus
    could have designed the USB header, to meet HP's requirements,
    rather than using the standard Asus header pattern.

    You could use an ohmmeter, and buzz from the USB pins on the front
    of the computer, to the cable assembly inside the case. Perhaps you
    can figure out the labelling of the pins that way. That would be
    safer than relying on the above info.

    Or, go to, and make up a "drive tray" interface for
    whatever interfaces the D845HV offers.

    Paul, Jul 23, 2004
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