The HV rectifier tube in the tv is a 3DC3. Not sure if it has the same issue with a filament falling out. After safely discharging the CRT and disconnecting the HV rect tube from its socket, I found out where the short was!
It appears that there was arcing from a bit of exposed copper wire leading to the tip of the HV rect tube. It seemed to perhaps be bypassing the corroded metal clip in the plastic nipple cap that goes over the tip of the tube.
Here are some photos.
https://imgur.com/a/wMMNkQ0
Any ideas or suggestions of how to handle this safely to stop the arcing?