pin layout tv-out connector Asus motherboard(s)

Discussion in 'Asus' started by KJ, Dec 13, 2005.

  1. KJ

    KJ Guest

    I own an Asus P4R800-VM and I would like to connect it to my TV set through
    the TV out. There is a TV-out connector onboard (6-1 pin, TV_OUT1) and I
    know there is a bracket/module for this (ASUS AV/S), but I do not want to
    use this (space and costs). I think it can't be that difficult to create my
    own, I do not see so much electronic parts on the module. It is just a
    matter of connecting cables. But I don't know the pin layout/meaning of the
    connector (it is not in the manual, all others connectors are)
    Does anybody know the meaning of the pins? There are 5 pins, I reckon there
    is 1 common ground, 1 composite signal en a couple for s-video/s-vhs
    (luminance (Y) & chrominance (C ))
    Pin1 from the connector is on the board & the manual topright)
    I saw that all/most Asus boards with tv-out have the same connector and
    probable the same pin layout.

    Mine is:


    |* *|1

    |* * *|
    KJ, Dec 13, 2005
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  2. KJ

    Paul Guest

    PDF page 38 of this new motherboard manual has a pinout:

    Post back whatever you discover, like whether the pin labels
    are correct or not. With the computer unplugged, it should
    be fairly easy to use an ohmmeter, and verify the two ground

    Paul, Dec 13, 2005
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  3. KJ

    KJ Guest

    Yes that's right indeed. I did find the two grounds pretty easy and those
    seem to be/are the same (the two on each side of the empty one). But now i
    found two 'readings' of the rest of the pins. One (yours) says oppsite to
    pin1 is the composite and the other says opposite to pin1 is one of the 2
    But that would mean that there also are two AV/S modules, and that seems
    kind of strange, don't you think?
    KJ, Dec 14, 2005
  4. KJ

    Paul Guest

    I think this is the AV/S (part number 90-C1OOBA-00XBY)

    The only other reference to the pinout I can find, is this
    posting by Fred. The diagram in this post could be the cable end
    or it could be the header - in other words, a mirror image.

    I doubt they would use the exact same header pattern and change
    the pinout. That wouldn't be very bright.

    I don't know where else to look, to verify the pinout. And it
    is likely that all three active signals will be driven by the
    same kind of driver circuit. That is why I didn't offer any advice
    on sorting the other three signals...

    Paul, Dec 14, 2005
  5. KJ

    KJ Guest

    Yes, i found the same posting of this Fred guy. But i would say that it is
    NOT a 'mirror' question. Because in his example the opposite to pin1 (gnd)
    is alway the composite, no matter how you look at it. The only mix up he
    could have made is the pin numbering i think. So pin6 = pin2

    Would you have any idea if it could harm to just test it? I would first go
    for pin1 & pin2, being a composite signal. Test it on a TV screen. If it is
    not the composite but a s-video signal it will not hurt my tv, won't it? And
    the same for mixing up S-video with composite....
    KJ, Dec 14, 2005
  6. KJ

    Paul Guest

    OK. I'm don't know too much about TV signals, but I'm willing
    to learn :)

    Here is a key posting, that may help us. The post at the bottom in

    I have one of those S-Video (4 pin) to RCA adapters. The poster on
    arstechnica, says the luminance and Chrominance are connected
    together with a capacitor, and with my multimeter, I do indeed
    find a 0.0033 uF capacitor between them. I also find the luminance
    signal tied directly to the center pin of the RCA connector on
    the other end.

    Based on understanding how that adapter works, here is what
    I expect will happen:

    1) Composite - If you connect this to the TV, it has three key
    components that make the TV work.

    The composite signal has "sync" mixed with it. The "sync tips"
    are parts of the signal that go below zero volts - that is
    sometimes referred to as "blacker than black". The TV cannot
    lock to the composite signal, unless the TV can lock to the
    vertical and horizontal sync component in the composite signal.

    The composite signal has both luminance and chrominance info.
    Luminance is the brightness, and in a sense, it could be considered
    a "black n' white" signal.

    The chrominance carries some kind of color signal. It
    could be phase encoded info, but since I cannot find
    any pictures on the 'net, of what the signals are supposed
    to look like, I'm not sure about that.

    2) Luminance - If you connect this to the TV by accident, my
    guess would be, that the luminance signal has "sync tips", so
    the TV should be able to lock to it. I would expect to see a
    black n' white signal on the TV set, accompanied perhaps by
    very bad color fringing.

    3) Chrominance - This likely has no sync mixed with it, so the
    TV should not be able to do anything with this. The filtering
    circuitry in the TV will be able to separate the chroma info,
    but the luminance component coming from the filtering will be
    zero volts, so the picture tube should be black. Without a
    sync component in the signal, the TV picture may roll, or
    if this is a modern TV set, the TV may indicate a "no-signal"
    condition. I think the reference color burst is also missing
    at the beginning of a display line.

    My guess is, you'll be able to tell the difference between the
    three signals. Composite will look good. Luminance will give
    a monochrome picture. Chrominance shouldn't give anything
    visual, as near as I can figure.

    Good luck :)
    Paul, Dec 15, 2005
  7. KJ

    fred Guest

    You're right, the pinout I gave was not mirrored and was of the header.
    From memory I got it from a manual and then confirmed it by inspection &
    buzzing out the faceplate board that came with my A7N8X mobo, the
    header on the mobo should be one-to-one for this as it is connected via a
    one-to-one ribbon.

    You should be able to get it first time by looking at the pinout I posted but
    it is pretty difficult to do harm as the grounds are ground and video signals
    always have a 75ohm terminator in series so accidentally shorting them to
    ground (but not any other rail) should not cause any damage.

    As I think Paul has advised, you usually need to make your TV connection
    first, then boot/reboot for the board/driver to activate the TV out. You might
    be able to make it 'always-on' somewhere in the nvidia setup but can't

    fred, Dec 17, 2005
  8. KJ

    KJ Guest

    I found out the pin/header layout for the TV_OUT connector/header on
    the Asus P4R800-VM (and perhaps other asus boards as well).
    There is a TV out header/connector on this board, but there's no description
    I've been testing and found it out. Now with only a cinch/rca or better a
    s-vhs/s-video female chassis part, one can create a cheap tv out. Asus sells
    the AV/S brackets but they are rare and more expensive.
    Here it is:

    5 1
    |* *|
    |* * *|

    pin1= GND
    pin2=composite signal
    pin3=is emtpy/not used
    pin4=S-video/s-vhs C(chroma)
    pin5= GND
    pin6= S-video/s-vhs Y(Luma)
    KJ, Dec 21, 2005
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