pin out for compaq presario 4764

Discussion in 'Compaq' started by Kevin Falconer, Nov 24, 2003.

  1. I'm bound and determined to find out why this NEW power supply from
    does not start up. The cmos battery is a good 3v and has been cleared.
    When trying to bench test I applied a 1/2 amp load to a 5v circuit
    jumpered green wire to ground wire and nothing. I dont think the green
    wire is the start up wire. I found that this was the correct color
    for an atx board, but my 2 connectors are inline not back to back like
    the atx schematic I saw. Even though the power supply was not running
    I picked up 12v on the purple wire, I wonder if this is the start up
    wire, I hate to
    jump it to ground until I'm sure. Thanks in advance for any comments.
    Anyplace I can get a compaq pin out schematic ?

    Kevin Falconer Fort Myers, FL
    Kevin Falconer, Nov 24, 2003
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  2. Kevin Falconer

    mike Guest

    There are probably non-standard pinouts, but if you have a real atx
    supply with a real atx connector, grounding the green wire should start
    it. If it's an older style AT supply with the standard 2 connectors,
    there should be a switch on the power supply to turn it on.

    supplies won't start without a load. Put one ohm on the 5V output
    and try to start it. Shorted board can prevent it from starting.

    Bunch of stuff For Sale and Wanted at the link below.
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    mike, Nov 24, 2003
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  3. Forgive me if you've already tried this, but try disconnecting and then
    reconnecting everything. Some times it just may be that simple.

    On the less simple side it just may be a bad power supply. It does
    happen to the best of them.

    Kevin Childers, Nov 24, 2003
  4. There are probably non-standard pinouts, but if you have a real atx
    Thanks Mike, I'm starting to believe this presario is not the "typical"
    connector. I'm seeing a lot of reference to a 20 pin connector which this
    board has none. I have two connectors lengthwise in a row with 6 terminals
    on each connector. Another connector all by itself with 6 wires also
    a lengthwise connector. It's possible this power supply is bad, but it is
    new. It's hard for me to condemn the MB untill I see this power supply
    work out of the computer to verify it is good. Are there any PSU's that DONT
    need to be switched on by the MB ?

    Kevin Falconer Fort Myers, FL
    Kevin Falconer, Nov 24, 2003
  5. Kevin Falconer

    Mike Calkins Guest

    Those units also remembered the sleep mode that the unit was in when the AC
    power was turned off at the back of the unit (power switch) when re-powered.
    Try pressing the sleep button on the front of the unit, after turning on the
    unit in the back.

    Mike in Houston
    Mike Calkins, Nov 24, 2003
  6. If I understand you correctly, I have seen this type board before. It
    is a proprietary version of a form factor AT board. I had an NEC GLobalist
    that had a similar sounding set of power cables. P8 & P9 connect side by
    side as on any other AT Board. The third power (?P10?) connector must be
    connected for the system to work and I suspect was an early attempt to allow
    the board to control system power. The bad news about it is that as with
    all older proprietary systems, it may be tough to find replacement part, in
    this case a power supply.

    FYI the 20 pin connector is for a form factor ATX mother board.

    Hope this helps.

    Kevin Childers, Nov 24, 2003
  7. I'm still not understanding the porprietary vs. reg board, my
    PSU does have a toggle switch in back I dont know if this means it
    would not use a turn on signal from the board or not. My two inline
    are p1 and p2 and then in the middle of the board is a single
    connector p9
    which contains the green wire and five others (6 wire single
    connector) I'd
    be surprised if I did get a bad PSU new from compaq but it is
    possible. I
    just want to make sure it is bad before I return it or call them. This
    system has that sleep mode also and I've played with that also to no
    If I could just get a "do this and it should run" from someone I could
    proceed from there but it seems this is not the standard board but if
    it is the
    green wire that is suppose to start it with a load on a 5v circuit,
    I've done this and it does not run. Compaq is hard to get a hold of,
    luckily it's not
    my main computer so time is on my side with the exception of any limit
    have to return this PSU if it is defective. Thanks for any comments !


    Kevin Falconer, Nov 25, 2003
  8. See embedded comments:


    Propreitary boards are uniquelly made boards produced by a single
    manufacturer. There is a general ad hoc standard for how boards are
    designed based on different form factors. Most boards follow said
    standards. occassionally a manufacturer makes a break from the standard
    creating a unique board, but it is than often incompatable to most others
    machines. Yours appears to fall into that catagory. without the third
    power connector it will not work. Most AT type machines only have the two
    power connectors, side-by-side with the black wires on each inboard or
    beside each other when connected to the mother board.
    If you have the correct PSU and have tried reconnecting it with still
    negative results, there are few other possibilities, beyond:
    A. Bad PSU
    B. Bad Switch
    C. Bad Power Cable (110/220 volt)
    D. Dead mother/mainboard

    I don't recall if this type PSU required you to jump it to get it to
    turn on with out a load, or if the fan would simply start when the power was
    turned on at the rear toggle switch. Most AT PSU run the fan with/without a
    load. Perhaps one of the other members can clarify this.

    A call to Compaq may be required, as this is about as much as I can
    remember. Unfortunately I sent that system to relatives in the Philipines
    so it is not available for reference.
    Kevin Childers, Nov 25, 2003
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