Ignoramus1540 wrote:
I have something that is a yellow steel box, called a civil defense
radiation detector.

http://www.radmeters4u.com/cdv715-new.jpg

I only have the yellow box.

No matter what I do, I cannot zero the thing. The needle goes all the
way to the right to Circuit Check. Does anyone know how to fix that.

Compare the voltage readings of your unit to what you see in
this schematic. Preliminarily, it looks like a switch problem
because the amplifier tube, V1 grid appears to be floating up
when it should be grounded with 'zero' selected.

Connect your negative meter probe to the negative battery
connector, not to ground.

http://www.vaughns-1-pagers.com/scie....htm#schematic


--Winston