You could also check your video settings. Once you've connected the cable and turned on the tv, you should go to your display settings in the preferences. There may also be a display icon in your Finder menu bar. Generally the default resolution over the S-Video is 800*600, check to see if the tv shows up in the display prefs and that the settings will work for it. Possbily the refresh rate needs to be adjusted.
“Maybe some day somebody will call me "Sir" without adding "You're making a scene"!!”