I just moved to a new place and trying to fix the doorbell. There are 2 doors, frond and back, neither one is working. I found a doorbell wire image on Google: enter image description here

However, it's very strange to see the following behaviors:

  1. 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?
  2. Disconnect all 3 wires in Chime. Now test Front and Rear buttons. Both show 0 Voltage as expected.
  3. 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.

  • Since rear now has 18 V does the chime sound when the rear button is pressed? – Jim Stewart Feb 21 at 23:16
  • In the chime unit what happens if you connect trans to rear? trans to front? This is what the buttons are supposed to do. – Jim Stewart Feb 21 at 23:19
  • The chime never works even I short the circuit on rear button. I just wonder why there's 18V between trans&rear even rear button wires are not connected. – Tom Feb 21 at 23:54
  • What happens if you short across the screws in the chime unit? Trans to rear? Trans to front? – Jim Stewart Feb 22 at 0:31
  • 1
    18V is measured between rear and trans, or front and trans, when the wires at doorbell button are not connected. – Tom Feb 22 at 3:49

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