If the doorbell rings the switch needs to be replaced.
Door chime transformer replacement.
It will likely be in the immediate vicinity though in the attic right above in the basement or in a nearby closet.
If the switch isn t the issue head to the chime or the indoor doorbell mechanism.
Measure the voltage on the transformer to see if it s producing enough electricity.
The voltage should be at or around 16.
If you need to know how to install a transformer for the first time call a qualified electrician.
First remove the wires from the doorbell switch the button mechanism and touch them together.
How to replace a doorbell transformer although the doorbell itself operates at low volatagge that is unlikely to shock you replacing a transformer involves working with line voltage circuit wires.
If the voltage is too low replace the transformer to repair your doorbell unit.
A look around the doorbell should give a pretty good idea where it might be.
Wiring a doorbell transformer is more complex than replacing a doorbell button or chime unit.
Test the doorbell transformer voltage by setting the meter on your voltage tester to 25vac volts alternating current.
Unlike the push button or the doorbell that reside in full view the transformer is concealed.