[old_tv_nut]

Two capacitors in parallel are used to tune the oscillator coil, a 150pf and a 33pf.
My guess from the Aerovox part numbers is that the 150pf is NPO, and the 33pf is N750 (negative temperature coefficient, minus 750 ppm/deg C, +/- 120 ppm/deg C).

This was obviously needed to counter the temperature coefficient of the coil, and still would not guarantee stable enough operation to do away with the color sync control. I still can't help thinking this was a stupid design when crystals were readily available, even if it did avoid some patent or other (which I don't know it did).

However, when I say crystals were "readily available" I suspect that at the time they were only being made from natural quartz and were still much more expensive than a few years later when synthetic quartz was in use, so maybe a few 1950 dollars instead of under 50 cents.