[Boatanchors] Johnson Viking 500 PA screen voltage:

[Craig C. Heaton]

To All:

I need a procedure to set the screen voltage for the PA tooob, a 4-400A, in
the Viking 500 I'm restoring. There are two resistors for this part of the
circuit, a fixed 20K 200W, and an adjustable 20K 200W resistor. The
adjustable resistor suffered from physical abuse, looks as though the
adjusting strap took a few hits and several wraps of the resistance wire are
broken.

I've replaced the damaged resistor with an adjustable Ohmite 25K 200W, now
its getting close to the time where I can plug the beast into a source of
electrons. I'd like to have the screen voltage close to the 400VDC listed in
the manual downloaded from BAMA website. Having gone through the manual
several times and not finding any mention of a starting setting, adj., or
checking for a desired AM operating PA screen voltage, I thought its time to
post another question.

Does anyone or has anyone been through this before and what is the procedure
to get in the ball park before applying power. If my guess is the same as
someone who has traveled this road, I'll be glad. Think its a voltage
divider circuit, and the first part of Ohm's law, E=IR, will work.

Thanks for any help,
73's
Craig