Doorbells consist of a push button, a bell, and a transformer. Diagnosing and repairing a doorbell that doesn't ring is relatively straightforward.
Step 1: Remove push button Remove the doorbell's face plate from the wall with a screwdriver and pull the push button away from the door jamb without touching the wires.
Step 2: Use circuit tester Use a circuit tester to measure the voltage flowing through the wires connected to the push button. If the circuit tester indicates 220 volts, shut off the main power switch controlling the power to the doorbell and replace the transformer.
Step 3: Disconnect wires Disconnect the wires from the push button if the circuit tester indicates no problem with the voltage. Holding the insulation, touch one wire to the other. If the doorbell sounds, the problem is with the push button.
Step 4: Sand terminals Sand the terminals on the push button with fine-grit sandpaper, and re-attach the wires with fresh wire ends; push the button. If the doorbell still does not sound, there is a problem with the interior of the push button. Replace the push button.
TIP: Doorbell push buttons are available in a variety of styles, including buttons that have a light behind them so that they can be seen at night.
Step 5: Remove bell cover Remove the cover of the doorbell and clean the inside if the bell makes a humming sound when you connect the wires. Also check for loose connections.
Step 6: Clean bell Clean the bell parts with a cotton swab and vacuum cleaner. If that doesn't fix the problem, call a professional or consider mounting a door knocker.
FACT: James M. Cain's novel The Postman Always Rings Twice was first adapted for film in 1946 and has since become a film classic.