Alexander Shendi
Don't know how to disassemble it further to get at the LCD display.
(EDIT: SOLVED: https://youtube.com/watch?v=a30iKSnvsjU )
Progress!
Does someone know where to get a new display? Part no. is IJC 14-4/7.
Switching on RKSB-104 Soviet-Era Dosimeter. Red variant. The battery hatch lid is missing and has been replaced by duct tape :) Made by BELVAR in Belarus. Apparently it's still working.
(INSERT: cheesy "3.6 Roentgen, not great, not terrible!" jokes)