The easiest solution to a broken electric doorbell is to put a little tape over the bell and hang a doorknocker. But it’s not too tough to repair the bell.
1) If you’ve lost power elsewhere, it’s likely a fuse or a circuit breaker. If not…
2) Remove the doorbell button, disconnect one of the wires and rub it against the other. If the bell rings, your problem is here. Clean the wires with sandpaper, reconnect them and try the button. If it doesn’t work, replace the button.
3) If this gets no results, find the doorbell transformer. The transformer takes high voltage from a regular circuit and “transforms” it into the low voltage your doorbell uses. Check for power by touching a voltage tester to the two wires supplying the transformer. If there’s no power, and your fuses or circuit breakers aren’t blown, the problem’s somewhere in the supply circuit.
4) If you have power and the bell still doesn’t ring, take the cover off the bell and clean the mechanism itself.
5) Still no luck? Join both bell wires at the button and at the transformer, so you have a continuous circuit. Using a circuit tester, see just how continuous it is. If it doesn’t light, you need to replace the wire. Buy new wire, attach it to the old, and pull it through walls, etc.
6) If the circuit’s good and there’s still no bell, try replacing the transformer. Look on the bell to find the right voltage. Shut off power to the circuit, and attach the new transformer using the old hookup as a guide.
7) If nothing’s worked so far, replace the darn bell. (Keep the existing wiring, button and transformer.)