That was really a hack that worked on that set sometime in it's past.
I'm guessing that the HV rectifier filament winding arced through at one time, so some clod used the focus rectifier winding instead.
It took some ingenuity to do it in that manner, but still hack at the same time. Plus poor lead dress.
When I found the same problem, I would cut out the filament winding and use a solid state replacement for the HV rectifier tube.
I still prefer a focus rectifier tube instead of that lousy stick.
