Composite to S-Video

[blackevilweredragon]

I made a circuit today that does the reverse of this, S-Video to Composite, as I wanted to use an S-Video only device on a Composite only monitor.

However, I thought, maybe I can connect something that is composite only, like an NES, or a Genesis II, and hook it up to my TVs S-Video ports, as the composite port broke off (this is my nice 20" TV)...

Here's the schematic for my S-Video to Composite adapter.  a similar circuit is floating around the net, but doesn't work as good (i found that having 3 caps instead of 1 makes the picture more stable)..

http://macteens.com/gallery/albums/userpic...o-composite.PNG

and here is the final product:  http://macteens.com/gallery/albums/userpics/TVcircuit.jpg

so, i tried using this circuit in reverse, have it take a composite source, and convert to S-Video, but this was the result..  as you can see, it's bad, and ugly...

http://blackevilweredragon.spymac.com/segastripe.jpg

however, using a composite source like my cable box, it doesn't look "as bad", but the cable box does yield dots moving on the screen all over the place..

http://blackevilweredragon.spymac.com/cablestripe.jpg

Is there anything I can add to my circuit to add the ability to cleanly do the reverse of what I designed it to do?  I would love to have an adapter that can go both ways...  Thanks!

(oh yea, this was my first soldering job btw, and i know it came out like crap, but my circuit works great for what i originally designed it to do..)

[blackevilweredragon]

hmm, this here is weird..  the shades of grey on eggman ship appear perfectly fine, but the yellow parts on his ship are showing the black vertical stripes...

what gives?

http://blackevilweredragon.spymac.com/eggman.jpg

[blackevilweredragon]

please?  3 days pass and no help?

[Segasonicfan]

hrmm, your post is a little confusing to me.  From my understanding, composite can be made from S-video very easily by simply combining Y and C.  I've never heard of using caps to do this, but I guess it should have the same effect.

Now, making S-video out of composite I'm not too familiar with.  I would imagine the quality to be somewhat lame in every case just because your decoding a single video signal.  If I were you I would do either one of two things:

1) open up your tv and wire in a composite jack from where yours broke off (this should be very easy).

2) open up whatever system you are using and tap the RGB lines to make a REAL S-video converter using the CXA1645/AD725 encoder chips.  I have info/schematics/pics on my site on how to build these.  That way you will get true high quality S-video.

-Segasonicfan  

[blackevilweredragon]

hrmm, your post is a little confusing to me.  From my understanding, composite can be made from S-video very easily by simply combining Y and C.  I've never heard of using caps to do this, but I guess it should have the same effect.

Now, making S-video out of composite I'm not too familiar with.  I would imagine the quality to be somewhat lame in every case just because your decoding a single video signal.  If I were you I would do either one of two things:

1) open up your tv and wire in a composite jack from where yours broke off (this should be very easy).

2) open up whatever system you are using and tap the RGB lines to make a REAL S-video converter using the CXA1645/AD725 encoder chips.  I have info/schematics/pics on my site on how to build these.  That way you will get true high quality S-video.

-Segasonicfan

well, the converting svideo to composite does need the caps, otherwise the picture looks very horrible, a lot of ghosting, and the dot crawl is so massive, it's not funny...

sadly, i don't want to go into the TV, and i don't want to mod my Genesis in any way (at the moment atleast)