Sega SG-1000 II Composite Video Modification

I have a Sega SG-1000 II that I have modified to work with composite video and audio. Originally it only supports RF output and only on Japanese channels, which makes it impractical and hard to use. My changes are based on the 171-5141 revision of the PCB, which is supposedly the first revision, with the TMS9918 video chip. According to the datasheet for the TMS9918, it can drive a composite video…