Rca ctc-63 hybrid with a weird video issue

[Turle]

Originally Posted by damen

RCA used several different high voltage protection circuits in the CTC63 chassis. Excessive high voltage caused by a defective VDR near the Horizontal output tube is the most common cause. If the VDR has gold colored end caps it's probably bad. Using a variac, or turning the horizontal hold control lowers the high voltage and that's why the picture comes back.

Interesting. I did notice when the video dies there’s a little neon indicator bulb on the chassis that lights. I’m assuming that has something to do with the HV regulation.

The vdr doesn’t have any gold colored caps but I suppose it wouldn’t hurt to check it anyway. How would I go about testing it?