As I know how you all love Steve Wozniak, I want to make the reference to this story, as part of Apple’s hardware timeline.
Thanks for the heads-up, Jorge Cortell, and thanks again for Woz’s biography you brought me, where by the way I haven’t found this particular point in a very fast review of the Apple ][ chapter…
From IEEE Spectrum:
Stephen Cass: Analog NTSC televisions generate color by looking at the phase of a signal relative to a reference frequency. So how did you come across this color test tool, and how did it work?
Al Alcorn: When I was 13, 14, my neighbor across the street had a television repair shop. I would go down there and at the same time, I had my father sign me up for an RCA correspondence course on radio and television repair. So, by the time I got to Berkeley, I was a journeyman TV repairman and actually paid my way through college through television. In one repair shop, there was a real cheap, sleazy color bar generator [for testing televisions]. And instead of doing color properly by synthesizing the phases and stuff like that, it simply used a crystal that was 3.58 megahertz [the carrier frequency for the color signal] minus 15.750 kilohertz, which was the horizontal scan frequency. So it slipped one phase, 360 degrees, every scan line. You put that signal on the screen and you’ve got a color bar from left to right. It really was really the cheapest, sleaziest way of doing it! […]