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How to Fix a Doorbell

Everyone knows someone who has a home with a broken doorbell. It’s so common that it’s difficult to know if the door hasn’t been answered because no one is home or the doorbell is simply broken. I can’t tell you how many people I know who simply ignore the bell and knock instead. While many homes are upgrading to wireless, battery-operated doorbells, there are still homes on the market with traditional transformer-controlled doorbells. If you’re one of the homeowners who still has this kind of doorbell, it’s time to take a look at why it may have stopped working.

Doorbell Components


Diagram of Doorbell Construction courtesy of Hydrargyrum

Despite the number of broken doorbells you may have encountered, they’re fairly simple devices. Most systems have a buzzer for the front door and one for the back door (typically identified by a single ring for the back door and two rings for the front). Rather than using a battery for a power source, wired doorbells are hooked up to the home’s electrical system through a transformer. This transformer adjusts the voltage in the system from 120-volts down to a much lower voltage (roughly 16-volts). The lower voltage means that the entire system can use smaller wires and connections while still signaling the bell. The bell is the final part of the system.

Additionally, lighted switches include a lightbulb to make them more visible. The bulb and the transformer both consume a very small amount of power since they are continuously energized.

Identifying Problems

There are only two real problems with doorbells. They either sound intermittently or they won’t ring at all.

Intermittent Ringing: If the doorbell is chiming when no one is there (and it’s not simply kids playing a prank), then there’s likely a short in one of the buttons. This is fairly uncommon due to doorbell design. However, if your doorbell works occasionally but not always, it’s likely a worn switch contact that needs to be replaced or simply a loose connection.

No Sound: If your doorbell simply does not work, it’s time to test a few different things. First, test both doorbells. If one works and the other does not, the problem is likely with the broken button or the wiring between the button and the transformer or doorbell. You should always check connection points to make sure they aren’t loose or broken. Then, check the wiring running between the doorbell and the button to make sure it hasn’t been damaged. If you have one available, you can use a fox and hound detector to test the cable to make sure it works.

If both doorbells fail to work, use a voltage tester to see if power is flowing to the doorbell. If you’re seeing voltage flowing to the button, then the transformer is fine. If the button, transformer, and wiring are all working properly, the issue is with the chime itself and may need to be replaced.

If, however, your initial voltage test shows no power flowing to the button, test the transformer. While it could still be a wiring issue, there’s a chance that the transformer has gone bad or is not receiving power itself.