Classic symptom of a bad VDR in the HV reg. Search drh4683 here.
He did a study of it & found a modern sub for it. The original
part was color striped. They subbed to a new p## a very nice blue color
with a Zenith 63-#### on it.
Trouble is the new OEM parts are going bad on the shelf.
If this helps pls let doug know & thank him for his work.
BTW always be sure the damper & HV reg tubes are per the layout chart !
There are 2 pairs that work together but subbing one screws things up.
Usually there it a caution sticker on the HV cage about it.
73 Zeno
LFOD !
73 Zeno