Adjust the counter by turning the sensitivity knob until the needle points in the main part of the scale. If the radioactivity is strong, the counter will read off-scale; if too weak, it will display a number too small to read accurately. Digital models might have a sensitivity knob also,...
Connect the negative lead of your ohmmeter to the anode of the SCR and the positive lead to the cathode of the SCR. Read the resistance value that is displayed on the ohmmeter. It should read a very high value of resistance. If it reads a very low value, then the SCR is shorted and...