First short circuit the push springs by inserting a knife blade or piece of wire so as to touch both of them. Then touch the two wires at the bell, one to each side wire coming from the magnet coils. If current is up to the bell and the coils are all right, a single stroke should result.
Replace the wires in the binding posts, clean the platinum on both contact screw and armature spring and try the adjustment. Troubles in the bell will be mostly similar to those before mentioned.
If no current has been obtained at either bell or push, and the battery is in good working order, the line must be tested for a cross or break.
If the wires are touching each other ([Fig. 35]) at some bare spot S between the bell and the battery, it will be shown by the metallic taste upon detaching one wire from the battery and laying it on the tongue T, together with another wire W from the disconnected terminal of the battery. The current will travel from the battery to the cross at S, then back along the second circuit wire to the tongue and through the short wire to the battery.
Fig. 35
If no current is obtained in this way it is probable that the wire is broken.
Fig. 36
The easiest way to find this is to take a bell to the battery and connect it between the circuit wires and the battery ([Fig. 36]).