I am trying to make my ColecoVision, a PAL unit, to output either S-video or composite. The usual easy guides refer to a chip in the RF unit which isn't there on the PAL unit, and a different RF unit too - the RF unit on PAL is just a stack of resistors, etc but no chip. The graphics processor, TMS9918 I believe it is, outputs Y (luma) and also B-Y and R-Y. Would combining R-Y and B-Y make Chroma (S-video) or is there another way? My electronics knowledge isn't great, so any help would be appreciated please - easy diagrams etc please! At the moment I have a ColecoVision in bits I can't use.