HOW TO TEST YOURSELF
Turn the control switch on and keep turning the potenti-
ometer to nearly the maximum. (This reduces the resistance.)
Make sure you have good batteries installed. Turn the speaker
on. Test the circuit by briefly touching the probe to the hand-
hold. The speaker should produce a sound like popping corn. If
it does not, check that your alligator clips are not bending the
spring terminals so much that other wires attached there are
loose. Finally, turn switches OFF.