Lian-Li Front Case Fans

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

I am posting this here since I am certain that many of you are using
Lian-Li cases.

My question is about the two front fans. These are 3 wire fans
connected to a small 3 switch circuit board with resistors that
controls the speed of both fans. My understanding on fan speed control
in general, is that by varying the voltage to the red fan lead
(usually connected to the yellow 12V Molex) one controls the speed,
The third wire, in general, (blue or yellow) is used for speed
monitoring, not for speed control.

However, the Lian-Li front fans are 3 wire and all are connected to
the small circuit board. There is no fan speed monitoring that I can
determine. My questions are:
1. How is the speed controlled in the Lian-Li ... by varying
voltage or by some other method using that third wire??
2. Are these special fans with the third wire (blue) set up to
control speed rather than monitor speed?

Norm
4 answers Last reply
More about lian front case fans
  1. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    In article <6h3r319s390pqn8irfpts1mk5hqa69l60v@4ax.com>, NSN@MAIL.COM wrote:

    > I am posting this here since I am certain that many of you are using
    > Lian-Li cases.
    >
    > My question is about the two front fans. These are 3 wire fans
    > connected to a small 3 switch circuit board with resistors that
    > controls the speed of both fans. My understanding on fan speed control
    > in general, is that by varying the voltage to the red fan lead
    > (usually connected to the yellow 12V Molex) one controls the speed,
    > The third wire, in general, (blue or yellow) is used for speed
    > monitoring, not for speed control.
    >
    > However, the Lian-Li front fans are 3 wire and all are connected to
    > the small circuit board. There is no fan speed monitoring that I can
    > determine. My questions are:
    > 1. How is the speed controlled in the Lian-Li ... by varying
    > voltage or by some other method using that third wire??
    > 2. Are these special fans with the third wire (blue) set up to
    > control speed rather than monitor speed?
    >
    > Norm

    I haven't a clue, but I'll contribute a couple of pictures:

    http://www.7volts.com/bb2.jpg
    http://www.7volts.com/cllbrfm.jpg

    The pictures are from http://www.7volts.com/lian_li_case.htm

    The controller board has a three position switch and what
    looks like two power resistors. In high speed, I would bet
    the red wire is connected directly to yellow (+12V). The
    medium speed, causes the current to flow through one resistor.
    The slow speed causes the current to flow through two resistors.
    You can verify this, by using an ohmmeter, and measuring from
    yellow to red, with the disk drive power connector disconnected
    from the power supply. To get to the red signal, disconnect one
    fan and touch the middle pin on the header on the controller
    board. The ohmmeter would read 0 ohms, then R1 ohms, then
    R1+R2 ohms, so the value you read should be increasing as you
    move the switch through the H,M,L positions respectively.

    It _looks_ like a simple resistive voltage reduction technique.

    The blue could be tacho, but I have no way of verifying that
    for you. I'd try to look up info on the fan, but I don't
    recognize that logo (is it trying to say "Adda" ?).

    You could unscrew the controller board, and examine it, to see
    if any connection is being made to the blue wire. If the blue
    wire is a no_connect, then at least you know it is not a fan
    control signal of some sort. But, I wouldn't take chances, and
    would try to track down info on the fan manufacturer. There
    are some fans that deliver a "locked rotor" signal, instead of
    tacho, on the third wire (like some Panaflo fans), and I
    don't think it hurts to connect one of those to a normal
    fan header. I would do my homework first, if possible.

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

    "NSN" <nsn@mail.com> wrote in message
    news:6h3r319s390pqn8irfpts1mk5hqa69l60v@4ax.com...
    >
    >
    > I am posting this here since I am certain that many of you are using
    > Lian-Li cases.
    >
    > My question is about the two front fans. These are 3 wire fans
    > connected to a small 3 switch circuit board with resistors that
    > controls the speed of both fans. My understanding on fan speed control
    > in general, is that by varying the voltage to the red fan lead
    > (usually connected to the yellow 12V Molex) one controls the speed,
    > The third wire, in general, (blue or yellow) is used for speed
    > monitoring, not for speed control.
    >
    > However, the Lian-Li front fans are 3 wire and all are connected to
    > the small circuit board. There is no fan speed monitoring that I can
    > determine. My questions are:
    > 1. How is the speed controlled in the Lian-Li ... by varying
    > voltage or by some other method using that third wire??
    > 2. Are these special fans with the third wire (blue) set up to
    > control speed rather than monitor speed?
    By using the third wire. However your basic 'premise', that using the
    third wire for a tacho, is 'standard', is flawed. This is only really
    'standard', in the PC marketplace. In normal use, there are a lot more
    varieties. As an example, I have a fan catalogue here. Out of fifty
    different basic 'types' (each of which then comes in different sizes, and
    speeds), only two have the tacho wire, while five have the third wire used
    for speed control. Of these, two use a thermistor on the line to vary a
    current and control the speed, one uses a DC voltage to vary the speed,
    one accepts a serial command, and the last one implements a bi-directional
    serial control/reading link, which allows the speed to b read, and the fan
    controlled with just one wire...
    The Lian-Li fans are probably standard speed controlled fans, but they
    might well use either a varying voltage, or a current change to actually
    control the units.

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

    Paul & Roger:

    Thanks .. you have answered my questions !! If a fan ever goes bad I
    will pull the little circuit board and check the schematics. I just
    went over to the ADDA web site and indeed, they have numerous
    configurations for that third wire .. one being speed control. I
    suspect that rather than directly changing voltage to the fan, the
    resistors are connected to the signal reaching the third wire and
    controlling the speed in that fashion.

    http://www.addausa.com/options/options-index.html

    Norm


    On Sun, 20 Mar 2005 16:03:16 GMT, "Roger Hamlett"
    <rogerspamignored@ttelmah.demon.co.uk> wrote:

    >
    >"NSN" <nsn@mail.com> wrote in message
    >news:6h3r319s390pqn8irfpts1mk5hqa69l60v@4ax.com...
    >>
    >>
    >> I am posting this here since I am certain that many of you are using
    >> Lian-Li cases.
    >>
    >> My question is about the two front fans. These are 3 wire fans
    >> connected to a small 3 switch circuit board with resistors that
    >> controls the speed of both fans. My understanding on fan speed control
    >> in general, is that by varying the voltage to the red fan lead
    >> (usually connected to the yellow 12V Molex) one controls the speed,
    >> The third wire, in general, (blue or yellow) is used for speed
    >> monitoring, not for speed control.
    >>
    >> However, the Lian-Li front fans are 3 wire and all are connected to
    >> the small circuit board. There is no fan speed monitoring that I can
    >> determine. My questions are:
    >> 1. How is the speed controlled in the Lian-Li ... by varying
    >> voltage or by some other method using that third wire??
    >> 2. Are these special fans with the third wire (blue) set up to
    >> control speed rather than monitor speed?
    >By using the third wire. However your basic 'premise', that using the
    >third wire for a tacho, is 'standard', is flawed. This is only really
    >'standard', in the PC marketplace. In normal use, there are a lot more
    >varieties. As an example, I have a fan catalogue here. Out of fifty
    >different basic 'types' (each of which then comes in different sizes, and
    >speeds), only two have the tacho wire, while five have the third wire used
    >for speed control. Of these, two use a thermistor on the line to vary a
    >current and control the speed, one uses a DC voltage to vary the speed,
    >one accepts a serial command, and the last one implements a bi-directional
    >serial control/reading link, which allows the speed to b read, and the fan
    >controlled with just one wire...
    >The Lian-Li fans are probably standard speed controlled fans, but they
    >might well use either a varying voltage, or a current change to actually
    >control the units.
    >
    >Best Wishes
    >
  4. Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

    I decoded the model number of the fan via the code sheet on the ADDA
    site. AD0812MS-A76GL.

    The above means that the fan is 12V DC brushless in aluminum frame
    with sleeve bearing, 7 blades. The third wire is dual function:
    protects motor via transistor and is also a speed sensor. Thus, those
    two resistors do directly regulate the voltage.

    Norm


    On Sun, 20 Mar 2005 17:13:14 GMT, NSN <nsn@mail.com> wrote:

    >Paul & Roger:
    >
    >Thanks .. you have answered my questions !! If a fan ever goes bad I
    >will pull the little circuit board and check the schematics. I just
    >went over to the ADDA web site and indeed, they have numerous
    >configurations for that third wire .. one being speed control. I
    >suspect that rather than directly changing voltage to the fan, the
    >resistors are connected to the signal reaching the third wire and
    >controlling the speed in that fashion.
    >
    >http://www.addausa.com/options/options-index.html
    >
    >Norm
    >
    >
    >
    >On Sun, 20 Mar 2005 16:03:16 GMT, "Roger Hamlett"
    ><rogerspamignored@ttelmah.demon.co.uk> wrote:
    >
    >>
    >>"NSN" <nsn@mail.com> wrote in message
    >>news:6h3r319s390pqn8irfpts1mk5hqa69l60v@4ax.com...
    >>>
    >>>
    >>> I am posting this here since I am certain that many of you are using
    >>> Lian-Li cases.
    >>>
    >>> My question is about the two front fans. These are 3 wire fans
    >>> connected to a small 3 switch circuit board with resistors that
    >>> controls the speed of both fans. My understanding on fan speed control
    >>> in general, is that by varying the voltage to the red fan lead
    >>> (usually connected to the yellow 12V Molex) one controls the speed,
    >>> The third wire, in general, (blue or yellow) is used for speed
    >>> monitoring, not for speed control.
    >>>
    >>> However, the Lian-Li front fans are 3 wire and all are connected to
    >>> the small circuit board. There is no fan speed monitoring that I can
    >>> determine. My questions are:
    >>> 1. How is the speed controlled in the Lian-Li ... by varying
    >>> voltage or by some other method using that third wire??
    >>> 2. Are these special fans with the third wire (blue) set up to
    >>> control speed rather than monitor speed?
    >>By using the third wire. However your basic 'premise', that using the
    >>third wire for a tacho, is 'standard', is flawed. This is only really
    >>'standard', in the PC marketplace. In normal use, there are a lot more
    >>varieties. As an example, I have a fan catalogue here. Out of fifty
    >>different basic 'types' (each of which then comes in different sizes, and
    >>speeds), only two have the tacho wire, while five have the third wire used
    >>for speed control. Of these, two use a thermistor on the line to vary a
    >>current and control the speed, one uses a DC voltage to vary the speed,
    >>one accepts a serial command, and the last one implements a bi-directional
    >>serial control/reading link, which allows the speed to b read, and the fan
    >>controlled with just one wire...
    >>The Lian-Li fans are probably standard speed controlled fans, but they
    >>might well use either a varying voltage, or a current change to actually
    >>control the units.
    >>
    >>Best Wishes
    >>
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