However, it's very strange to see the following behaviors:
- Disconnect both frond and back buttons, because they could be broken. Test the voltage in Chime. Rear&Trans shows 18V and Front&Trans also shows 18V. It's weird because both buttons are disconnected. Is it correct to say that the Chime is directly connected to the Transformer?
- Disconnect all 3 wires in Chime. Now test Front and Rear buttons. Both show 0 Voltage as expected.
- Connect all 3 wires in Chime. Now test Front and Rear buttons. Rear has 18V but Front has 0V.
I also have a wire tracer, but unfortunately I still couldn't find the transformer. I was thinking if there's a broken wire on front door button because it shows 0V. If I use wire tracer on front door button, I can here the tracer sound on Chime and rear door button. I'm very confused why my front doorbell has 0V.