DuMont RA-102 vertical transformer bad?

[M3-SRT8]

Originally Posted by Phil Nelson

Well, the screen image is definitely unstable, although I'm not sure if I would ascribe it only to the vertical. The whole image seems to expand and contract in both dimensions -- horizontal and vertical -- slightly and rapidly. I can also see faint "retrace"-like horizontal lines, both light and dark. It's hard to capture with cellphone video, but these brief clips give an idea what's happening:

http://antiqueradio.org/art/DuMontRA...ngScreen01.mp4

http://antiqueradio.org/art/DuMontRA...ringScreen.mp4

Edit: I just noticed that the "retrace"-like lines are light in the top half of the screen and dark in the lower half. ????

I wonder if instability in the high voltage supply could cause the fluttering in screen size? Adjusting the Regulator Control and Voltage Control on the power supply chassis doesn't affect this problem. My high voltage meter shows a steady 10KV output, although that meter may not be sensitive enough to show such small, rapid fluctuations.

My RA-102-B3 Club 15 does that, on occasion. I also could not measure any fluctuations in power from the 2nd Anode.