Okay, can't move forward until I clear this up

[TinCanAlley]

Originally Posted by zeno

The schematic shows the elements in order, also physical order.
Hi cathode V=low bright Low Cathode = brite pix.
This is why it gets bright when you pull the taps.
You are putting a high RELATIVE voltage on the G-1
& tons of electrons go towards it.

G1 is fixed, its negative compared to the cathodes.
Make it more neg & brightness goes down. Its a control
grid, make it too neg & you turn off the tube. Make it
to + things get too bright. You can actually melt
some power tubes with a + G-1 voltage.

G-2 is positive related to the K's & G-1 so it pulls the
electrons along, more + means more brightness.
When electrons get there they see the focus at 6KV &
rush along to that & then the 30KV HV.

73 Zeno

So if a higher cathode voltage makes it darker, then that's why the setup doesn't work. When in setup, the voltage to the cathodes goes up to 188 - 180V from around 143 - 149V. Now all I need to do is figure out why the voltage goes up that high when switching from normal to setup. Anything in the setup circuit stand out as a possible cause of increased voltage?