Here’s a short, simple tutorial on how to build a cable and connect your laptop to a TV, using the S-Video output port of the former and the SCART input port of the latter. I’ve looked for something like this for days, and I think it can be very useful to someone.
You can modify an existing cable, or build your own.

Knowledge base

If you have a 7-pin female connector, no problem: a pin is dedicated to composite, so simply link that pin to the appropriate one in your SCART male connector.
If you have a 4-pin connector, thing are a bit more complicated. This connector gives us only luminance, crominance and two masses, according to the following scheme:

The vaste majority of televisions doesn’t accept s-video signal with separated crominance and luminance, but only the composite, that is a “mix” of the previouses. In the SCART connector luminance is pin 20, crominance pin 15, but pin 20 is also used as VIN (Video composite in). Traditional TVs take video signal from pin 20, receiving this way only luminance: the result is a b/w vision!

Here’s the scheme of such a cable:

Modify the standard cable

How can we solve that problem? Simply, we have to join luminance and crominance in one signal (the composite one). The simplest way is to connect directly the two signals, soldering pin 15 and pin 20 togheter. This way you will be able to see colours, but they will not be reproduced correctly. To make things better, you have to put a capacitor in your circuit in order to give crominance some phase delay.
The correct scheme:

This cable works good. You can obtain a different result, according to your needs, varying the capacitance.

In short

So, what you have to do?

• buy a male s-video, a male scart connector, and some cable.
• locate pins
• the 2 masses of the s-video have to be connected to scart pin 18
• connect crominance, trough a 470pF capacitor, to pin 20
• connect luminance to pin 20

A tip: try to put the capacitor as near as possible to the s-video connector.
I don’t know if my explanation was clear, I don’t speak english well. If you have doubts, send me an e-mail or sign the guestbook.

Tags: hardware, howto, notebook

This entry was posted on Monday, July 19th, 2004and is filed under Hardware & Software. You can follow any responses to this entry through the RSS 2.0 feed. Leave a response, or trackback from your own site.