S-Video card issues on Atari 600XL

[The Mr. Video]

Hi, I found this thread containing instructions on how to make a small S-Video board and I figured I'd try to make one for my 600XL for a summer project.

However, I seem to be having some problems with the picture signal. When I test the S-Video, I get the results below for about a second and then my TV loses signal. Adjusting the trimmer and even using a different S-Video cable makes no difference.

 

Below is how I built and installed the card. The orange wire is luma, blue is chroma, and the striped wire is ground. The board itself uses a 10uf 50v capacitor for chroma and outputs to an S-Video cable.

[TGB1718]

Assuming you've wired it up ok, the S-Video circuitry is very susceptible

to crosstalk and noise, you need to keep all wire lengths to an absolute minimum.

Also, can't see the back of the board you have used, if it's like the "vero board"

i.e. long copper strips, there will be extra crosstalk between those lines too.

 

Lastly is the cable to your monitor adequately shielded, again another source

of interference.

 

Personally I would have used shielded wires for the Orange and Blue wires

taking the shield to 0V

 

[+kheller2]

In your post over here: 

  you mentioned "composite" which this would not be.  Your monitor / tv has to support separate Chroma/Lumina inputs (and modern TV's even if they have that ability, usually dual purpose a single set of jacks or dongle that you must configure in the settings to be composite or  C/L.).

 

I am very surprised that this thing works on a NTSC 600XL at all, but tapping line 1 off the RF mod should get you something close to composite but probably not balanced properly for signal.

 

Assuming you have everything wired correctly, and it still doesn't work, we can spend time troubleshooting it or just get UAV.

 

 

[The Mr. Video]

1 hour ago, kheller2 said:

In your post over here: 

  you mentioned "composite" which this would not be.  Your monitor / tv has to support separate Chroma/Lumina inputs (and modern TV's even if they have that ability, usually dual purpose a single set of jacks or dongle that you must configure in the settings to be composite or  C/L.).

I guess I should have clarified that I was trying to get S-Video instead of composite from the start and wanted to use a standard S-Video cable for the output since my CRT supports it. The cable I was using at the time didn't output a picture for some reason so I wired chroma and luma to RCA plugs and plugged them into my TV's composite jack to see if I get anything from either of them. The picture of the TV was taken just after adding the trimmer and replacing the S-Video cable.

[reifsnyderb]

I've seen that mod and didn't trust it.  So, I bought a few components and soldered them in place to get S-Video:

 

 

If you want to try this, PM me as I've got extras and made some decent documentation for it.