[MrFixr55]

In almost any post-war TV I ever worked on, the HV Rectifier gets its power from a few turns of very well insulated wire around the frame of the flyback acting as a secondary. Is this a transformer powered set or are the tube heaters in series? If parallel and transformer powered (and based on the tube layout in RadioMuseum, it appears so), and if the damper and Horizontal Output Tubes are mounted on the PC instead of the chassis frame, look for a poor solder joint on any of the posts bent up from the metal chassis frame that support the PC Board. Often there is not a continuous ground plane on the PCB, and they rely on the individual posts for ground connections. I have fixed several RCA B/W and color TVs from the 50s to early 60s in my youth that had this condition.