No ticking at the CRT socket, and those connections are clean & bright.
Where I do hear a wee ticking, however, is near the base of the 1B3GT HV rectifier tube. Corona inside the HV cage was a common problem with these sets, the subject of a Dumont service note. I thought I had solved that with multiple applications of corona dope, but perhaps more is needed.
I took another video with a test pattern instead of broadcast video from my agile modulator:
http://antiqueradio.org/art/DuMontRA...ngScreen02.mp4
I don't know if that tells us anything new, but at least I know I'm not watching interference from the home broadcasting setup.
Phil Nelson