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My friend has a simply wired doorbell. Front door only. The doorbell stopped working after a power outage. Power came back on - no doorbell. I checked all the wiring - doorbell at the front door to chime box to the transformer. Visually, nothing wrong. I checked the transformer. My voltage meter registers it at 12v. The transformer says 16VAC on it. Zero voltage on the chime box and doorbell.

Here's what I've done to troubleshoot:

Remove the doorbell button and touch both wires together. No ring. Tried a new doorbell button - no ring Replaced the chime box - no ring Replaced the transformer - no ring. The new transformer registered at 12 volts too. Both the old and new transformer - the wires into the house - that's 120v and looks good.

At my house, my doorbell works. When I test my transformer, it comes back to 12v too. My volt tester tells me 12v, 24v, etc. It doesn't have a 16v on it.

So what could be going on here? It could be a break in one of the wires, but I don't have the tools to test for that, nor the room to crawl in the attic and find the wires and visually trace them. I wouldn't even know where to begin on that.

Any other troubleshooting steps I can take?

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    Hello, and welcome to Home Improvement. Sounds like you have a wiring problem, and the power outage was incidental. And, you should probably take our tour so you'll know how best to participate here. – Daniel Griscom Oct 31 '19 at 23:07
  • It may not be the right kind of meter, or maybe the meter technique needs adjustment. I infer you're in the USA -- doorbells here almost universally work at 16 volts AC. The markings of 12v and 24v on your voltage tester imply it might be designed for measuring DC volts -- automotive systems, perhaps. It's expected that a DC meter would measure 0 when measuring an AC source like a doorbell system. – Greg Hill Oct 31 '19 at 23:13
  • "It could be a break in one of the wires, but I don't have the tools to test for that" - all you need is your meter set on Ohms, and a wire nut where the switch goes, to check for continuity. You only need access where there's connections. – Mazura Nov 1 '19 at 2:22
  • Sadly, my stupid volt tester doesn't do ohms. But I think I'll get a new one that does do ohms... – steve02a Nov 1 '19 at 3:50
  • Actually went out and bought a better multimeter today. I'll be testing tomorrow. – steve02a Nov 1 '19 at 5:55
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What kind of meter are you using? To check the wiring turn the power off First check the button. measure the button if not lit it should be open or very high resistance, when pressed very low resistance (ohms) But you should see a change in either case.

I would then take the chime directly across the transformer. If it doesn't ring my guess would be the transformer as a 16vac transformer unloaded would normally be closer to 20v rms.

Next check the wires, you have a line connected to the transformer and a line connected to the chime, remove one of those wires and measure the resistance (ohms scale) from the wire removed to the other it should be a high value close to infinite (unless it is lighted button then remove it and retest) next short the doorbell wires and repeat the resistance measurement now it should be low probably less than 20 ohms if these 2 measurements are correct the button wiring is fine not shorted or open.

The last item is the chime itself but I think you tested it.

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