Asus A7V-ML Again

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

Thanks to rob for previous info, the reason I got the Pavillion 7909 for
free is that the power supply died and a new one was going to cost its
previous owner upwards of £80.00, so he gave it to me, I have an old power
supply unit but it does not have the 3 pin cable for the PS FAN connection
on the board which I think runs the 2 fans, cpu & case, my question is can I
just power the 12v & ground on the board and leave the rotational one
disconnected, or do you need the rotational one connecting.

Cheers
7 answers Last reply
More about asus again
  1. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <T5MQd.2387$74.1006@newsfe1-win.ntli.net>, "Dajan"
    <dave.routh@ntlworld.com> wrote:

    > Thanks to rob for previous info, the reason I got the Pavillion 7909 for
    > free is that the power supply died and a new one was going to cost its
    > previous owner upwards of £80.00, so he gave it to me, I have an old power
    > supply unit but it does not have the 3 pin cable for the PS FAN connection
    > on the board which I think runs the 2 fans, cpu & case, my question is can I
    > just power the 12v & ground on the board and leave the rotational one
    > disconnected, or do you need the rotational one connecting.
    >
    > Cheers

    See page 35 here. The three fan headers are outputs. They
    all have +12V on them.

    http://www.asus.com/pub/ASUS/mb/socka/kt133/a7v-m/a7vm-101.pdf

    A power supply that has monitoring on it, can have two kinds of
    monitoring. A power supply with a two wire cable, but a three pin
    connector, is meant for RPM monitoring. The two wires on the
    cable are Rotation and GND. In extreme cases, it is possible for
    only one wire to be used - Rotation - because the ground is
    already established through the power cabling to the PSU.

    The second monitoring type, consists of two wires but a two
    pin header. This is a thermistor temperature monitor cable and
    should not be connected to a fan header (it doesn't even match,
    so it should be obvious it doesn't go on a fan header). The
    thermistor allows a motherboard equipped with a thermal monitor
    input, to tell you what the internal temperature of the power
    supply is. I don't see one on the A7V-M.

    I notice in the picture of the BIOS screens in the manual, that
    the PSU header rotation signal is not monitored. I guess that means
    the PSU header on the motherboard, could be used to connect a
    chassis exhaust fan (one of those fans that doesn't have a
    rotation signal on the cable). And then the chassis header can be
    used for any fan that has the rotation signal, even a PSU rotation
    monitor cable.

    Not everything Asus does makes sense.

    Just a guess,
    Paul
  2. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    Thanks Paul
    The 3 fan headers are not all outputs, I actually took the old power supply
    unit out and there was a 3 pin lead from the unit to the PS FAN header, the
    cpu lead is connected to the cpu header and the chassis fan is connected to
    the other header which to me means the power from the power supply goes to
    the the PS FAN header input which then feeds the other 2


    "Paul" <nospam@needed.com> wrote in message
    news:nospam-1602051452440001@192.168.1.177...
    > In article <T5MQd.2387$74.1006@newsfe1-win.ntli.net>, "Dajan"
    > <dave.routh@ntlworld.com> wrote:
    >
    >> Thanks to rob for previous info, the reason I got the Pavillion 7909 for
    >> free is that the power supply died and a new one was going to cost its
    >> previous owner upwards of £80.00, so he gave it to me, I have an old
    >> power
    >> supply unit but it does not have the 3 pin cable for the PS FAN
    >> connection
    >> on the board which I think runs the 2 fans, cpu & case, my question is
    >> can I
    >> just power the 12v & ground on the board and leave the rotational one
    >> disconnected, or do you need the rotational one connecting.
    >>
    >> Cheers
    >
    > See page 35 here. The three fan headers are outputs. They
    > all have +12V on them.
    >
    > http://www.asus.com/pub/ASUS/mb/socka/kt133/a7v-m/a7vm-101.pdf
    >
    > A power supply that has monitoring on it, can have two kinds of
    > monitoring. A power supply with a two wire cable, but a three pin
    > connector, is meant for RPM monitoring. The two wires on the
    > cable are Rotation and GND. In extreme cases, it is possible for
    > only one wire to be used - Rotation - because the ground is
    > already established through the power cabling to the PSU.
    >
    > The second monitoring type, consists of two wires but a two
    > pin header. This is a thermistor temperature monitor cable and
    > should not be connected to a fan header (it doesn't even match,
    > so it should be obvious it doesn't go on a fan header). The
    > thermistor allows a motherboard equipped with a thermal monitor
    > input, to tell you what the internal temperature of the power
    > supply is. I don't see one on the A7V-M.
    >
    > I notice in the picture of the BIOS screens in the manual, that
    > the PSU header rotation signal is not monitored. I guess that means
    > the PSU header on the motherboard, could be used to connect a
    > chassis exhaust fan (one of those fans that doesn't have a
    > rotation signal on the cable). And then the chassis header can be
    > used for any fan that has the rotation signal, even a PSU rotation
    > monitor cable.
    >
    > Not everything Asus does makes sense.
    >
    > Just a guess,
    > Paul
  3. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <fUNQd.836$Yj2.450@newsfe4-gui.ntli.net>, "Dajan"
    <dave.routh@ntlworld.com> wrote:

    > Thanks Paul
    > The 3 fan headers are not all outputs, I actually took the old power supply
    > unit out and there was a 3 pin lead from the unit to the PS FAN header, the
    > cpu lead is connected to the cpu header and the chassis fan is connected to
    > the other header which to me means the power from the power supply goes to
    > the the PS FAN header input which then feeds the other 2
    >

    This is how the fan power works on my P4C800-E, as measured with
    an ohmmeter. The CPU fan measures open circuit, implying the MOSFET
    located next to the header, is the culprit.

    ATX20pin_+12V ---------+----------+-------- ------------+
    | | | | |
    | | ------ |
    PSU Chassis | CPU
    Fan Fan MOSFET Fan
    +12V +12V for Q-fan +12V

    Your board likely looks like this, as I don't see Q-fan in
    the manual. The reason there is +12V on the PSU connector, is
    if you want to connect a chassis fan to it. A PSU fan should
    be getting its juice from inside the PSU, and only the rotation
    and GND should be connected via the PSU fan monitor cable.

    ATX20pin_+12V ---------+----------+---------------+
    | | |
    | | |
    PSU Chassis CPU
    Fan Fan Fan
    +12V +12V +12V

    Using an ohmmeter, measure from the +12V pin on the 20 pin
    motherboard connector, to the fan headers. If there is an
    open circuit, then your theory, shown below, would be correct

    ATX20pin_+12V - --+----------+---------------+
    ^ | | |
    | | | |
    no connection ? -+ PSU Chassis CPU
    Fan Fan Fan
    +12V +12V +12V

    ATX connector pinouts are on page 29 of this doc. You are looking
    into the ends of the power supply in that figure, so apply the
    correct transformation when viewing the connector on the mobo.

    http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf

    If, in fact, there is continuity from ATX20pin_+12V
    to the fan headers, there is no need for power to flow out
    of the PSU fan wire, to the other fan headers. It would
    be a redundant connection, and a dangerous one at that,
    as more than one amp could flow down the PSU fan cable to
    the motherboard, and that is not a good idea. I think the
    fan header connectors aren't rated for more than about
    an amp. And that is why the PSU fan cable should only use
    two wires, so there is no sneak path for the +12V to flow
    via the third wire. The motherboard +12V current should flow
    through the power path via pin 10 on the ATX power connector,
    as that pin and wire can handle 6 amps.

    HTH,
    Paul
  4. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <fUNQd.836$Yj2.450@newsfe4-gui.ntli.net>, "Dajan"
    <dave.routh@ntlworld.com> wrote:

    > Thanks Paul
    > The 3 fan headers are not all outputs, I actually took the old power supply
    > unit out and there was a 3 pin lead from the unit to the PS FAN header, the
    > cpu lead is connected to the cpu header and the chassis fan is connected to
    > the other header which to me means the power from the power supply goes to
    > the the PS FAN header input which then feeds the other 2
    >
    The only other evidence I have to offer, is your PSU fan cable is
    not part of the ATX power supply standard.

    http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf

    And, that means a standards compliant power supply would not be
    able to make the fans run, if your theory was correct. Asus
    wouldn't do something like that. The motherboard has to work
    with any power supply meeting the ATX standard, and capable of
    supplying the necessary load current.

    It is indirect evidence, but the only other way I can think of
    to convince you.

    Paul
  5. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    When the person took the power supply unit to the computer shop for a
    replacement he was told that the type he had with a 3 pin connector was a
    special one and would cost over £80.00, unusual as the are nomally £15.00,
    the 3 core lead definately went from the unit, (which incidently is smaller
    than a normal unit and fitted inside a housing to make it fit the case) to
    the PS FAN header which means it must be the feed to the board which feeds
    the other 2 headers

    Dave

    "Paul" <nospam@needed.com> wrote in message
    news:nospam-1602051610150001@192.168.1.177...
    > In article <fUNQd.836$Yj2.450@newsfe4-gui.ntli.net>, "Dajan"
    > <dave.routh@ntlworld.com> wrote:
    >
    >> Thanks Paul
    >> The 3 fan headers are not all outputs, I actually took the old power
    >> supply
    >> unit out and there was a 3 pin lead from the unit to the PS FAN header,
    >> the
    >> cpu lead is connected to the cpu header and the chassis fan is connected
    >> to
    >> the other header which to me means the power from the power supply goes
    >> to
    >> the the PS FAN header input which then feeds the other 2
    >>
    > The only other evidence I have to offer, is your PSU fan cable is
    > not part of the ATX power supply standard.
    >
    > http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf
    >
    > And, that means a standards compliant power supply would not be
    > able to make the fans run, if your theory was correct. Asus
    > wouldn't do something like that. The motherboard has to work
    > with any power supply meeting the ATX standard, and capable of
    > supplying the necessary load current.
    >
    > It is indirect evidence, but the only other way I can think of
    > to convince you.
    >
    > Paul
  6. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <IpPQd.1479$8n6.1229@newsfe3-win.ntli.net>, "Dajan"
    <dave.routh@ntlworld.com> wrote:

    > When the person took the power supply unit to the computer shop for a
    > replacement he was told that the type he had with a 3 pin connector was a
    > special one and would cost over £80.00, unusual as the are nomally £15.00,
    > the 3 core lead definately went from the unit, (which incidently is smaller
    > than a normal unit and fitted inside a housing to make it fit the case) to
    > the PS FAN header which means it must be the feed to the board which feeds
    > the other 2 headers
    >
    > Dave
    >
    OK. I went to the HP site, and tunneled down to their parts site.
    The Pavilion 7909 has a Bestec ATX-1956F listed as the 200W
    power supply for the unit.

    http://partsurfer.hp.com/cgi-bin/spi/main?sel_flg=partlist&model=P1019A&HP_model=P1019A&modname=Pavilion+7909UK+%28United+Kingdom%29+%28P1019A%29&template=main&plist_sval=ALL&plist_styp=flag&dealer_id=&callingsite=&strsrch=&keysel=%3F&catsel=%3F

    After an Altavista search, here is the first site I found:

    http://www.affordablesurplus.com/bestec-atx-1956f-power-supply.asp

    "NOTE:  Your power supply may not have all of these connectors.
    In that case, the unused connectors can be tied off with no
    problem. The important thing is to ensure that this unit has
    at least the connectors that are connected to your motherboard
    and peripherals with one exception.  If the original has a P7,
    P9 or FAN/C 3 Pin connector...no problem.  The replacement unit
    operates without this connector."

    What that says, is the Bestec supply internal fan was remotely
    controlled by the motherboard. In other words, the power supply
    had a weird requirement, and not the motherboard. If you use
    a standard ATX power supply as replacement, a standard ATX power
    supply can control its own fan. So, a £15 PSU can be used, as long
    as it has current outputs at least as good as the current numbers
    listed on the side of the original power supply. The
    affordablesurplus site lists these numbers on their replacement:

    3.3V@16.7A 5V@21A 12V@10A -5V@0.2A -12V@0.5A +5Vsb@2A

    Knowing how HP designs stuff, they like to have more fan control
    than Asus is used to. The info on the affordablesurplus web site,
    suggests this is how the Bestec works. The Bestec was getting
    fan power from the motherboard, so the Asus motherboard must have
    a fan control channel. Since the A7V-ML is an OEM design, Asus
    can make changes like that for a big customer.

    | Bestec Fan Design
    |
    ATX20_+12V ---- ------------x >-----+12V_fan
    | | |
    ------ ------x <----- RPM
    | | |
    | v --x >----- GND
    Asus fan RPM | |
    Control | |
    GND

    If the replacement ATX power supply has no fan cable, the mother
    board will not care - if the BIOS is monitoring the RPM signal,
    set the BIOS to [Ignore] for the PSU fan. The PSU will decide
    how fast to run the fan - when the PSU gets hot, the fan will
    speed up, without any involvement from the motherboard.

    | Replacement Fan Design
    |
    ATX20_+12V ---- ------------x -----+12V_fan
    | | | | --- GND
    ------ ------x | |
    | | | ^ ^
    | v --x (Internal fan power)
    Asus fan RPM | |
    Control | |
    GND

    If the replacement ATX power supply has a fan monitor cable, it
    will have two wires. The +12V to the fan will come from an
    internal circuit. You could connect the fan monitor cable to
    the Asus motherboard if you wanted - I should only have two
    wires, as the fan power is being provided from inside the PSU.

    | Replacement Fan Design
    |
    | -----< (Internal fan
    | | power)
    ATX20_+12V ---- ------------x |-+12V_fan
    | | |
    ------ ------x <----- RPM
    | | |
    | v --x >----- GND
    Asus fan RPM | |
    Control | |
    GND

    So, I'm afraid your friend was getting the shaft, for that
    £80 replacement.

    HTH,
    Paul
  7. Ummm the PSU that does not have the 3 Pin plug is the up dated version guys and it has an internal controller for the PSU fan so the PSU does not need the 3 pin connector from the MOMBO both are interchangeable with that MOMBO on the Newer version disregard the 3 pin connector on the MOMBO
    that is a Power out Only like all fan 3 Pin connectors.
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