Look at CRT socket. The 3 color outputs have white paint on
the PCB. They are marked E B & C measure the C in DC volts.
The G-2 should be marked too. Use a meter rated at 800-1000
volts as it can be adjusted that high. Normal voltage is apx 400-500.
Almost all in line tubes will have the same set up & its common
to make tests here.
73 Zeno
LFOD !