Attention Old Coot Gotham Needs Your Help

[vts1134]

I feel like I should have a "Bat Signal" to shoot up in the sky to alert Bill. Maybe it could be in the shape of a soldering iron or a 10BP4 .
I have another head scratcher that I have been working through for a couple of weeks and I'm out of ideas. I am working on the television chassis on a 730TV1 and I have something bogging down my B+ supply. It sort of feels like deja vu as I just had this problem not long ago on another set. That one was much easier to go through and figure out where the problem was created, this set is stumping me completely. Here is the whole schematic for reference http://www.earlytelevision.org/pdf/R...-Sams-70-7.pdf
I have taken a shot of the section below where I can isolate and remove the problem. This section is just past the main filter capacitors (and choke) on the B+ supply. If I remove BOTH positive leads on C4 my B+ supply is healthy. If, however, I connect EITHER positive lead on C4 my B+ drops to right around 90V. I have temporarily swapped in two replacement caps for C4 and it makes no change. I have removed the wiper leads on R5 and R6 to isolate the yoke and there is no change. I'm at the end of my current skill set. What am I missing?