Recapping a 1955 RCA KCS92d

[Electronic M]

The vert tube is usually not able to take out the HV... granted some sets take boost voltage from the flyback to feed the vert and if the vert stage has an issue causing it to overload the boost that can also load down the HV indirectly.

The fly sounding strained sounds like a more telling lead... if the h osc is too far off the correct frequency then the HV output and sweep will collapse. The entire h output/fly/yoke is a big tuned circuit and needs the right frequency to work. Also the waveform and amplitude need to be at least close to the right for the system to work... when it it right it should be a high pitched whistle tone no screeching or crackling.

Make sure to get a schematic...TVs are complex and diverse so flying blind without a schematic is going to waste more money in burning through your valuable time than buying 10 schematics will cost.