[old_tv_nut]

I contacted an old colleague who reminded me that Zenith worked with Motorola to make Zenith-designed ICs at least by the late 70s as they were developing their one-chip monochrome IC. I still think it was some other company that's no longer around for the early 2-chip color system. I looked up the IEEE paper on the color sync IC by John Rennick, but unfortunately he is the only listed author and the manufacturer is not mentioned.