Swann HD Doorbell

Seeing screws with wires attached to them is a good sign the doorbell is hardwired (not battery operated), in a battery operated fixture the wires would be soldered to a circuit board.

If you live in the U.S. you are probably dealing with 12 to 24v at the chime, though the power should still be shut off at the main panel before you start working.

Here is a good guide to troubleshooting a doorbell.

Troubleshoot a doorbell switch

1. Unscrew the switch from the house and pull it away to tighten any loose wires.

2. If that fails, bypass the switch by shorting across the terminals with a screwdriver blade or by removing the two wires and touching them together. If the bell rings, replace the switch. If not, twist the two wires together and move on to the next step.

3. Connect the two wires to the two terminals; push the wires back into the wall and screw on the switch. If new mounting holes are required, start the holes with an awl and drive in the screws.

Troubleshoot a transformer

1. Locate the transformer, and inspect and tighten low-voltage wire connections to it.

2. If neither doorbell works, use a multitester set to the 50-volt AC range to test the transformer. Touch the probes to the two terminals. If the reading is within 2 volts of the transformer's rating, troubleshoot the chime. If not, go on to the next step.

3. Shut off the power to the transformer's circuit at the service panel, and remove the outlet-box cover. To test for power, pull out the black circuit wire and remove the wire nut. Probe the black and grounding wires with a neon tester. Repeat the test for white and grounding wires. Tighten any loose connections.

4. To replace a faulty transformer, remove the low-voltage wires. When there is more than one wire at a terminal, tape them together for easier rewiring.

5. Shut off the power to the doorbell circuit at the main service panel. Remove the outlet-box cover and disconnect the wires from the old transformer, then disconnect it from the box or the box's cover.

6. Attach and wire the replacement. Connect the transformer's green wire to the bare grounded wire and its other two wires to the black and white circuit wires. Attach the outlet-box cover and secure each low-voltage wire or set of wires under a terminal.

Troubleshoot a chime

1. Remove the chime cover, which may snap or screw onto the base, and inspect all wiring connections.

2. If the connections look good, set a multitester to the 50-volt AC range, then touch one probe to the transformer terminal and the other to the nonworking front or rear terminal. If it fails the test, replace the faulty wiring (see "Replace doorbell wiring," below). If the chime has power but neither doorbell works, replace the chime (go on to steps 3 and 4).

3. To replace a chime, remove its cover. Disconnect and label the wires for easier rewiring. Remove the mounting screws and the old chime.

4. Thread the wires into the back of the new chime and mount it to the wall with the provided screws and anchors. Attach low-voltage wires to their respective terminals and replace the cover.

Replace doorbell wiring

1. Disconnect the faulty wire at both ends and loosen or remove all accessible wire staples.

2. Twist together one end of the existing wire to an end of the new wiring and tape the splice, using very little tape. Pull the existing wire to draw the new wire through holes, staples and wall or ceiling cavities. Pull it through one section at a time rather than all at once. Staple as needed.

1. Dust off the tone bars. Loose debris dampens their vibration.
2. Check the tone bar mounts and positioning. If a bar is crooked or out of position, it won't ring as well.
3. Check the hammers on the solenoids. If there is debris, clean it off. If they have dried out or cracked, remove the hammer. That will definitely increase the volume.