RCA 630TS - no high voltage

[Electronic M]

Originally Posted by nasadowsk

Check the rectifier socket, and HV cap - try the set with the cap discoonected. They act weird at times…

+1.
If you can draw a decent arc from the plate lead for the HV rectifier with it disconnected from that tube but with it connected you don't get HV it means the rectifier is bad, the HV doorknob cap is bad, the HV rect heater winding is bad (in one or more ways) or the connection between the tube pin and the point of measurement has failed.

If you happen to have a CFL bulb or a small neon indicator lamp you can place it in proximity to the flyback and the tube plate leads coming off it and see if it lights up. It normally should in those areas.