CD V-700 Model 6b
This is a Geiger counter originally used for Civil Defense purposes. This came in non functional. I checked all the semi conductors, diodes and transistors. I went through the resistors and found them mostly in tolerance. I tested the meter with an ohm meter and a 10k series resistor. I started with a 1 meg resistor and worked my way down dividing by half until the meter registered 1/2 scale. That satisfied me if the meter was good or not.
The unit came in with a spare used G-M tube. It only needed the loose pins super glued. Once the new G-M tube was in I measured about 600 volts on the tube. The scope showed the typical fly-back transformer weird wave shape by simply putting the probe tip near the fly-back transformer.
This was something new for me to work on. A hybrid mix of solid state and a G-M tube. It was fun. See the pictures below.
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