If you have a constantly ringing doorbell, either the doorbell button is jammed or the wires going to the button are shorted together. To test the button, first turn off the power of your home. Once the power is off, then remove the button form the door frame and disconnect one of the two wires connected to it. Turn the the power back, if the doorbell does not ring, this is a sign that the doorbell button needs to be replaced. If the doorbell dose ring, than the problem is a short between the two wires of the doorbell. To fix the doorbell wiring, turn the power back off again and look for frayed wires, frayed insulation or bare wires that are touching. Once the defective doorbell wire is found, use electrician’s tape to wrap them where necessary. If you are unable to find the short you will need to replace the wires.
The parts for a typical doorbell system contain the push button, the chimes or buzzer, and the transformer. The transformer allows the doorbell to operate at a low voltage around 6-24 volts. Wired into the doorbell circuit at a junction box, the junction box steps down the voltage level form the regular 120 volt circuit to the 6-24 volt circuit.
The drawing at the top shows how a one-button doorbell system is wired. When your doorbell doesn’t ring, or worse, you have a constantly ringing doorbell, the problem may lay in one of the wires shown in the picture to the top.
CAUTION: To figure out most doorbell problems, you’ll need to have the power source to the doorbell connected. But if you are going to work on the wires in the junction box of the doorbell, make sure to shut off the power to the circuit and test the circuit to be sure its off.
This diagram was exactly what I needed to repair our doorbell – after sifting through dozens of useless tips and diagrams from other sites, this picture made the repair a piece of cake. Thank you.