Success! The 33K resistor between the brightness control wiper and CRT cathode was measuring close to 500K. Also, the pairs of 100 ohm and 150 ohms resistors on the dual 6BG6 horizontal output tubes were high - more than double in some cases.
Replacing all those great improved the brightness and contrast functionality and cleared up the hor. distortion.
Finally, I unmounted the focus coil from the CRT neck so the 5AXP4 would auto-focus correctly.
Next thing to fix is the power switch which is currently stuck ON.
Bandwidth is pretty good but there is some slight horizontal waviness. Perhaps some 60Hz is leaking in.
This is the focus coil I unmounted by removing three spring loaded screws.
