When that doorbell suddenly stops working or starts making odd sounds it can be quite frustrating. Fortunately, repairing or replacing a broken doorbell is well within the skills of most homeowners. All it takes is some knowledge, and of course the right tools.
No Ring at All
If the doorbell does not ring at all, use these steps to diagnose and repair the problem:
Step 1 - Check the Button
The problem may lie with the button and not the doorbell itself. Doorbell buttons can easily be damaged by weather conditions and a buildup of dirt. Remove the cover and clean the contacts using either fine grit sandpaper or an emery board. Then, use a screwdriver to pry up the contacts to make the doorbell ring. If the doorbell still does not ring, remove the button, disconnect the wires and touch the ends together. If the doorbell chimes, the problem lies with the button. If the bell does not sound, or sounds very faintly, the bell unit is the problem.
Step 2 - Check the Wires
If the doorbell will not sound, the wires may be loose at either the sound unit or at the transformer. The next step is to check the wires at both ends by wrapping the wires in electrical tape if they are frayed, and tightening them if they have become loose. Also make sure that none of the exposed wires are damaged, and that all wires are connected to the bell terminal.
Step 3 - Check the Transformer
The transformer should also be carefully checked by restoring power to the circuit to which the transformer is connected. The transformer is generally on the junction box located either in the basement or near the circuit box. Set a multi-tester for an ACV scale with a 50-volt range, then touch the transformer's low voltage terminals with the probes of the multi-tester. If there is no voltage signal, the transformer needs to be replaced.
Quiet or Strange Ring
If the problem is a doorbell that makes an abnormal sound, the following steps will be needed to resolve it:
Step 1 - Check the Clappers or Plungers
The doorbell generally will not work properly if the clapper or plungers have become dirty. Dirty clappers or plungers result in a muffled or muted sound. Removed the cover to inspect the points on the chimes or bells. They can then be cleaned using a cotton swab dibbed in alcohol, or an old toothbrush which has been coated with lighter fluid.
Step 2 - Replace the Grommets
If the clapper or plunger is not dirty, the problem may be with the rubber grommets. If those grommets are hard or brittle the doorbell may have very muted tones when pressed, and replacing those worn out grommets will restore the proper sound. These rubber grommets are available at most electrical supply stores, and they simply attach to the support holes on the tone bars.
Step 3 - Replace the Transformer
If more than one chime or bell is attached to a single transformer, the tones may be muted or too low in volume. Replacing the transformer with one with a greater low-voltage output will help both doorbells ring clearly.