This is an ultra short user guide for cold war CCCP made DP-5B geiger counter.
The battery elements are located into a bottom compartment. You can get them by opening and splicing the 3x 1.5V elements of a 4.5V flat battery pack. I’ve then wrapped with heathshrink pipe to be insulated against each other.
The first thing to do after switching on is setting the voltage converter. Actually that’s the first position after had clockwise rotated the main selector. The needle must be into the black mark zone of the scale. Use the voltage regulation knob carefully… the “peak'” of the correct position is very sensible.
The second thing is rotate main selector to the first position of the lowest scale. You must do that to zero the instrument. Now you can measure gamma or beta sources and change the various scales.
This is with gamma filter off.
Gamma filter on and 0 because of background.
This is a radium tube with strong gamma emission. I’ve shut down my lab’s light to show the phosphorescent dials.
This is with backlight ON.
The device have it’s own check source. 100kBq Sr90 under a protective cover that can be rotated to put the probe into a precise position.