Testing Russian DP-5V on uranium marbels with SI-1 homemade interface and with homemade geiger counter GMS-8 ( with SBM-20 GM tube). The DP-5V is from year 1985, calibrated in 2002 and put out of service in 2005. I bought it on ebay with cut off probe, so I had to repair it. And this video shows that it works.
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