[Coco] Coco1&2 Composite video

[Luis Antoniosi (CoCoDemus)]

Hi all,

I managed to get composite video out from the s-video circuit:


 S-VIDEO.png<https://docs.google.com/file/d/0B1Po4gOY2zl7Qko4dGJONi1hakU/edit?usp=drive_web>

By doing this with Luminace and Chrominance:

Luminance   ----------------|
                            |
Chrominance -- Var. 1K Ohm  +------ Composite Out
                            |
Chrominance -- 0.05uF ------|


The image is pretty good. Better than any S-Video/Composite converter I
have here.

But this circuit will ruin the Luminance signal by mixing the chroma signal
to the luma. So when using together the s-video output it get a bad s-video
output. I would like to design a universal coco1/2 board which outputs
s-video and composite.

My question is: Is that possible to isolate the circuit to not have the
Croma returning to the s-video ? Should I extract a second luma out of the
6847 only for the composite ?

See the video, is in portuguese but you only need to look at the image:

http://www.youtube.com/watch?v=V-k8ZJKnoDc




-- 
Long live the CoCo