Adjusting the HV on a 7" Electrostat
 

Most of the Electrostatic sets I've seen have a spring with a wire around the 1B3 rectifier. I assume this is to adjust the H.V.?

What is the proper procedure for this? do you just slide it up and down till you get the maximum brightness and therefore, presumably the maximum H.V.?

I don't have a H.V. probe :dunno:

Eric

feedback coupling spring on 1B3
 

Eric,

That spring is a coupling capacitor to provide positive feedback to the power oscillator tube. I recall seeing a drawing with measurements as to where the spring should be, so much just below the bottom edge of the plate inside the 1B3 on my Rider's service doc on the Motorola 7VT5R I have. Since every 7" set I've seen can benefit from the HV cranked to the max I would just adjust this feedback spring for the smallest brightest raster, provided you stay within range of your focus pot.

Rob