RCA CTC4B "Gainsborough" picked up in San Francisco

[Tom9589]

Think of the CRT and the shunt regulator as two variable loads on the flyback. When the CRT has a bright scene, it becomes a greater load while the shunt regulator becomes a lessor load. Conversely, a dark scene causes the CRT to become a lessor load while the shunt regulator becomes a greater load. The whole idea here is to present a more or less constant load on the flyback and the circuitry upstream of it. The real question is whether the designers specified the flyback so that it can withstand this combined load (CRT plus shunt regulator) on a continuous basis without having too much of a temperature rise.

I always liked the Zenith pulse regulator although it wasn't as well regulated as a shunt regulator. I never had to replace a Zenith flyback with a pulse HV regulator.