To fix a doorbell not working is mostly easy. Usually it’s the button but check the transformer. A broken doorbell may be in the wiring.
It is easy to repair most doorbell problems once you understand how they work. If for some reason your home has some unusual high-voltage doorbell or alarm system this column will be no help to you.
So EVERYONE, please pay heed to any warnings or unusual systems you may encounter when working on anything electric.
For most homes a transformer supplies low voltage power to the doorbell and the button(s). The output of the transformer is low voltage, safe for human contact when working on the system. The output can be 10 to 16 volts.
The transformer is usually located in the basement not far from the doorbell upstairs. It should be connected to the outside of an electrical box with the 115-volt connections inside. Do not work inside the box without first disconnecting power to that circuit.
Two exposed screws on the outside of the transformer are the low voltage output and you should see bell wire running in several directions. One pair of wires run to the front doorbell button, one pair to the rear button (if available), and two or three wires lead up to the bell.
The most common problem with a doorbell is at the buttons. If it is broke in the off position nothing will happen, but if it is stuck on, then the doorbell will make a humming sound (if it is not burned out). If the unit hums or is warm, one of the buttons is stuck on. Remove the button(s) and disconnect it from the bell wire. Once disconnected make sure the wires are not touching each other. Is the doorbell still humming? Bummer-the wires are shorted together somewhere in the run between the button(s) and the doorbell. This repair requires a detective to trace the wires and find where they were injured. A nail from a door molding or a screw from the screen doorframe could have cut the wire.
If your doorbell is cold and not humming, try touching the bell wires together and listening for the bell to ring. If you get a tone, you have found your problem. Just replace the bell button and forget you read eight paragraphs to get this far.
If there is no sound you have three possible problems: a bad transformer, a bad doorbell, or broken wires in-between.
If you found the transformer in the basement, and the wire leading to the doorbell, you can jump the button and ring the bell directly from the transformer from the basement.
If it rings, your problem is in the wires between the button and the transformer.
If it does not, you could have a bad transformer or a bad doorbell.
Now, I suggest purchasing an inexpensive multi-meter for about $15. Set it for A/C volts and the 50 or 100 scale. Do not set it for 10 or less volts.
First test the transformer. Is it putting out any power? If yes take the doorbell off the wall and connect it directly to the transformer with two low voltage wires. If it rings you have a wire problem. If not, take the doorbell to a hardware store and test it there.
If you cannot repair the problem, you can install a wireless doorbell system. The outside buttons are battery driven and the bell plugs into the wall anywhere in the house.