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From: Paul on 15 Dec 2005 05:52
In article <439ff03f$0$11073$e4fe514c(a)news.xs4all.nl>, "KJ"
<iemand(a)microsoft.com> wrote:

>
> 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....

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
particular.

http://episteme.arstechnica.com/6/ubb.x?a=tpc&s=50009562&f=67909965&m=1460994923

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
From: fred on 17 Dec 2005 08:04
In article <439ff03f$0$11073$e4fe514c(a)news.xs4all.nl>, KJ
<iemand(a)microsoft.com> writes
>
>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....

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
remember.

HTH
--
fred
Plusnet - I hope you like vanilla
From: KJ on 21 Dec 2005 06:58

"fred" <not(a)for.mail> schreef in bericht news:FIShOIAOyApDFw+S(a)y.z...
> In article <439ff03f$0$11073$e4fe514c(a)news.xs4all.nl>, KJ
> <iemand(a)microsoft.com> writes
>>
>>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....
>
> 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
> remember.
>
> HTH
> --
> fred
> Plusnet - I hope you like vanilla
Thanks!
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
available.
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)


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