In this video, electrician Steve Krasner repairs a broken doorbell with This Old House host Kevin O'Connor.
1. Unscrew and remove the old, broken doorbell from the house.
2. Locate the doorbell's low-voltage transformer in basement, crawlspace or utility closet.
3. Test the transformer with an electrical tester to ensure it's working properly.
4. Use electrical toner to trace the wires from transformer to doorbell location. Toner will confirm that wires are in working order.
5. If necessary, extend old wires to doorbell location by attaching new wires.
6. Connect the two new wires to the screw terminals on the rear of the new doorbell.
7. Screw the new doorbell to the house.
8. Remove the cover from the new chimes and screw its mechanism to the wall.
9. Connect the existing chime wires to the two screw terminals on the new chimes.
10. Snap the cover onto the chimes.
11. Remove the toner from the transformer and reattach the doorbell wires to the transformer to complete the electrical connection.