Solder blobs on the chassis board seem unlikely. I had the neck board off the tube while I was working a fair distance from the chassis board.
Not impossible but unlikely. My gut feeling is that the gentle prod on the neck board was coincidental to the failing vertical deflection. At least that's been my response in terms of troubleshooting.
As for low resistance, I've been systematically going through and looking for low resistance/continuity across many points.
This is what I've found so far:
IC541 (V-out)
pin 2 vcc+ -- 1kohm
pin 4 vcc- -- ~200kohm
pin 5 out -- 10ohm
TP600 (+B) -- 3ohm
standby +5v -- 14kohm
Test point 600 stands out at 3ohm. However, looking at the schematic it may simply be its easiest path to ground. Not sure. Seems a bit unlikely?
Flyback transformer. I'm not sure how these readings should be interpreted. This may be completely normal but almost all pins show continuity to ground and have very low resistance. Here's the board layout -
https://imgur.com/JjXXuVc
pin 11 (ABL) - non-continuous/infinite resistance
*The remaining pins tested rise to about 100ohm and settle to about 1ohm
pin 9 (+13v)
pin 7 (-13v)
pin 6 (heater)
pin 4 (200v)
the remaining pins are either NC or not even there (like pin 3) but they all are continuous ie under 100ohm.
If this isn't usually the case for flybacks then maybe that's the issue. What would cause a flyback to fail? Would all test points show such low resistance to ground?