I just replaced 1.5k resistor on my 25LC20 (before reading this) old one looked all right but measured low (1.26k). Low resistance is also a sign of heat stress/damage. Maybe it's there to protect rectifier and or Pic tube or people from 22kv!
The HV rect filament wire was hardened from heat and had 1/2" bare stripped connections to socket! Who did that? Not factory?
There was a lot of wax melted from flyback!
The 2,2k final Horiz Output screen resistor looked cooked - was very high 11k! but set worked.
Will soon see if this corrects my vertical lines (is this "diodehausen"?
screen picture)