You won't know that your doorbell has gone down until you hear an unfamiliar knocking at the door. The doorbell may be small and often overlooked, but it is an electrical appliance, so you need to take safety precautions when repairing your chimes. Whether the tool that alerts you to the arrival of visitors is a chime, bell or recorded soundtrack, they all work courtesy of a low-voltage current system that runs through a transformer. Learning where this transformer is located can help you out with repairs.
Flip a circuit breaker or check for a blown fuse to begin the repair of a doorbell. The fault of a broken doorbell may merely be that power is not making it to the system.
Go outside and check the button that causes your doorbell to signal. Unscrew the doorbell face plate and check the wiring for loose connections. After tightening the wires, check to see if the doorbell is working.
Unscrew the two wires again if the doorbell still isn't working and touch them to each other. Make sure to grasp the wires over the insulated part. A ringing bell is a sign that the doorbell switch is broken. Clean the contacts with special contact cleaner or penetrating oil and try the switch again. If it still does not cause the bell to ring, replace the entire push-button unit.
Locate the bell that chimes and clean it of any dust or grease that has built up, if nothing happens at all when you touch the wires together. Any part of the bell system that may cause it not to work should be cleaned, including the bell and the stem that taps the bell
Find your transformer and measure the voltage at the screws that you find attached to the bell's thin wire. The voltage should measure between 6 and 24 volts AC. Touch the ends of a jumper wire to each of the output terminals. If this causes a small spark, the problem is located in the transformer. No spark means the transformer is working fine.
Check voltage at the input terminals if there is no spark, while making sure not to check with a jumper wire. Doing so could cause a shock or cause you to get burnt. A voltage reading between 110 and 130 volts AC means that the transformer is bad and needs to be replaced.
Test for a broken wire if the transformer is working right by running wires from the two output terminals of the transformer to the two bell terminals. Make sure you have enough wire to make this test. Replace the wiring if the bell rings. Replace the bell if the bell does not ring after running this test.