You put a micro/milliammeter in series with each of the cathodes and
urn on the guns one at a time, or there are tube checkers that can do
the same thing. Another possibility is to raide the filament voltage
of the blue crt slightly to raise the emissions. Depending on the set,
you can add a few turns of wire to the horizontal output transformer
(HOT) and put them in series with the filament voltage if it is derived
from the HOT, measuring the voltage as you add the turns. IF you get
the connection so that the voltage decreases, you must reverse the
connections. A lot depends on how familiar you are with tv set guts.

H. R. (Bob) Hofmann




Yikes, no not the HOT, you put a few turns of wire around the core of
the flyback transformer. Tricks like this and rejuvenating the guns are
generally not advisable on projection CRTs though, they're already run
very close to their limits and trying to get more life out of a tired
one usually just kills it.