Door Bell Transformer, non-automotive

Hey Folks,

Another "off-topic" question for you all. But since it involves low-voltage, I thought it would be acceptable...

Recently, the doorbell in my house has started to fail. Last night, after it stopped working again, I checked the voltage on the contacts on the transformer - attached directly to the outside of my electrical panel. When I touched the contact screws, the voltage registered about 1.5 volts for a split second and then dropped to nothing.

Should this not be a consistent 12 or 24 volts DC? I think my transformer is pooched.

Disconnect the bell wires off the transformer before you condemm it.. if you have a short in the wiring on the low voltage side then you wouldn't see any voltage. If you still get something other than 12/24 volts with the wiring disconnected then you might have a bad transformer.. check input voltage also.

Jim

Door bell transformers are AC voltage not DC. So, put your meter on AC and check it. Also I found a site you can look at.

https://www.hometips.com/home_probsolver/hps05/hps_checktransformer.html

Thanks for the replies Guys.

flobee4 - I actually found the same site yesterday (thanks). I was surprised to learn that the transformers are AC, but I did go home and check it last night. Found out I have a constant 16V AC at the transformer - so it's OK. Then I checked for power at the bell and found that there is no power there when the door button is pressed. So, I guess I have a bad wire somewhere?!?!? Not sure if I'll be able to find it, and may need to install something new - maybe something remote.

Any suggestions???

I'm sure you did this already, but did you try to unscrew the door bell button outside and short the 2 wires together.  Those buttons outside go bad.  If that still doesn't work then you must have a broken wire somewhere.  I usually use 4 conductor telephone wire when wiring a doorbell, so if a wire goes bad, i usually have 2 more that are good. Hopefully your electrician did that also.

Frank

flobee4 wrote:

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I'm sure you did this already, but did you try to unscrew the door bell button outside and short the 2 wires together...

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Yep, done. I actually replaced the button last year because it was broken. All appears well at this time.

flobee4 wrote:

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...I usually use 4 conductor telephone wire when wiring a doorbell, so if a wire goes bad, i usually have 2 more that are good. Hopefully your electrician did that also.

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Excellent idea on the redundancy - - unfortunately, I don't think I have that kind of situation. They were building houses "on-the-cheap" in the 70's.

Zilverado wrote:

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Thanks for the replies Guys.

flobee4 - I actually found the same site yesterday (thanks). I was surprised to learn that the transformers are AC, but I did go home and check it last night. Found out I have a constant 16V AC at the transformer - so it's OK. Then I checked for power at the bell and found that there is no power there when the door button is pressed. So, I guess I have a bad wire somewhere?!?!? Not sure if I'll be able to find it, and may need to install something new - maybe something remote.

Any suggestions???

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There are two terminals at the doorbell button.. you should read 16vac across them when the button isn't pressed, and 0vac when the button is pressed. IF this is what you get, your problem is elsewhere.. try the ringer module.

Jim

Mad Scientists wrote:

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There are two terminals at the doorbell button.. you should read 16vac across them when the button isn't pressed, and 0vac when the button is pressed. IF this is what you get, your problem is elsewhere.. try the ringer module.

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So, I should get 16V at the button - - OK, I'll check. I was not sure if this would work, but I guess it should...

By ringer module are you referring to the bell itself, 'cause I get nothing there. Or is this module something else?