Measuring HV in an electrostatic set, tips?

[Electronic M]

The filtered HV leaves the cage on the thickest wire and is easily accessible on the HV terminal strip under chassis below the cage. There's a HV wax cap under the socket board that should be changed and usually a resistor in series with the HV wire leading out of the cage that should be checked while you're in there.

The HV is independent of the sweep circuits so if the HV is working you could have a raster, horizontal or vertical line (one of the sweep circuits not running) or even a dot (no sweep working).
Some sets you can hear vertical and or horizontal some you can't. Electrostatic sets tend to be quieter than electromagnetic sets unless something is not working properly.