I tested a #10 headset using an ohmmeter and there was continuity between pins 2 & 3. There was continuity across the right hand earphone and the left hand earphone, measured at the screws.
Take your multimeter and use the low ohms range (I trust you have one
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Measure from the common to test points 1, 2 & 3. If 1 is good then there is continuity across right headphone. Go to point 2. If good fine but if open there could be a break in wire between earpieces. If 2 is good then measure point 3.
At each point your should have a low resistance reading. Using the ohmmmeter is a better way to test the headset & cables than listening to CBC.
If the set measures high resistance (open circuit) then scrub down & prepare for surgery. Are the headset's Canadian (Chamois cushions)?