TV-37 vertical hum?

[miniman82]

I really don’t think it’s magnetic directly to the CRT, there’s nothing near it currently and the wiring is being shielded by being under the chassis. This is AC getting into the deflection or video circuit that I can see with my scope moving slowly through the waveforms. If I look at the vertical oscillator waveform for example instead of being nice and flat I can see a half cycle of AC distorting it slowly moving from right to left. This corresponds with the waving seen in the picture tube, so I think the AC is getting in at a grid someplace and getting amplified because there’s no way such a small signal would have such a large effect on the geometry of the picture directly. You’re talking about maybe 2.5v of AC against the hundreds of deflection and ultor volts seen by the tube.