Reply To: Koryuu s-video interference

[megari]

Another thing that came to my mind, although it doesn’t seem to quite fit the symptom, is a cost-cutting measure some cheap CVBS/S-Video combo cables use: instead of having 3 separate wires for CVBS, luma and chroma, only CVBS and chroma are wired, with luma being substituted with the CVBS signal. This completely ruins the S-Video picture, yielding dot crawl, just like in CVBS. What makes this even worse is that combing the luma component of S-Video is not done, as proper Y/C separation is assumed.

But, as said, the symptoms do not quite match that extreme scenario, at least considering the photos @leewrigley posted, which do not look like the dot crawl you get with composite, rather than a mesh pattern more indicative of a coupling effect due to crosstalk.