I got some odd readings when testing the tapped filament resistor in circuit so took it out for a closer look.
It turns out that the resistive element inside is fine, but the tap for the UHF pilot light is open.
I got curious and scrapped away the coating around the open tap. Putting pressure on the metal plate reestablished continuity. I noticed some corrosion too.
I'll replace it with some power resistors.
