How to Fix a Doorbell

Before disconnecting the old wires, label them with strips of tape: "Front" for front bell, "Back" if there's a back bell, and "T" for transformer. Mount the new chime on the wall, and attach each wire to its appropriately labeled terminal. If the old wires aren't long enough, splice a short length of 18-gauge wire onto each one. Push the button to make sure the chime's working, then put on its cover.