Yes get a raster BEFORE you spend money on it.
Dont forget the HV filament wire often arcs too. Anything from there to the CRT conection can arc. You will probably have to pull the chassis. Be very careful
not to pull off any wires going to the tuner or controls.
If you pull the 5GH8's for testing be SURE to mark them & put them
back in the same place ! And DONT spray clean the tuner.
73 Zeno
LFOD !