# Doorbell Transformer 24v keeps burning out



## raylo32 (Nov 25, 2006)

Sounds like there may be a short in your wiring that is frying the transformer.


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## heynowjerry (Nov 10, 2012)

raylo32 said:


> Sounds like there may be a short in your wiring that is frying the transformer.


Thanks much.

So that would take weeks for the short to knock out the transformer? I wouldn't notice right away?

And I should be able to test the incoming doorbell feed and driveway feed and notice the short?

Thanks again..


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## raylo32 (Nov 25, 2006)

Not sure why it would be intermittent but a short is more believbale to me than 2 defective transformers in 2 weeks. Where/how does the wire run out to the driveway? Does it get perturbed in any way? Also, it's possible the contact set on the driveway or the doorbell ringer is the culprit. Get out a meter and start checking stuff....


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## bobelectric (Mar 3, 2007)

Look into getting a wireless driveway alarm.


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## Bobka (Nov 4, 2012)

open up and inspect the plunger unit...you may have a bad solenoid..it is sticking and drawing current....grease and or dirt build up will make her sticky....try replacing the whole nine yards..:thumbsup:


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## dmxtothemax (Oct 26, 2010)

Are you really sure that the replacement transformer has the correct current capacity ?


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## heynowjerry (Nov 10, 2012)

dmxtothemax said:


> Are you really sure that the replacement transformer has the correct current capacity ?



Actually, the chime unit is new, and working fine, or so it seems. The transformer is a dual 16/24, dependent on wiring.

The previous unit was 16 only, worked for 10 years, although after chiming would buzz for 2-4 seconds afterward. Finally, the plunger stuck and I bought another unit. Driveway worked like a charm for 10 years. THis is really confusing.


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## dmxtothemax (Oct 26, 2010)

Do you know for sure what the current draw is for the new unit ?
If for instance the new unit needs 2 amps,
and your transformer is rated for 1 amp,
then this would explain the burn outs !
Trannys burn out for two main reasons,
1 - Faulty construction.
2 - Overloaded.

Try putting a amp meter on the tranny and measure 
what currents are flowing.


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## joed (Mar 13, 2005)

heynowjerry said:


> The previous unit was 16 only, worked for 10 years, although after chiming would buzz for 2-4 seconds afterward. Finally, the plunger stuck and I bought another unit.


Would seem to indicate you have a sticking button or shorting cable. Probable cause for burning out transformers.


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## heynowjerry (Nov 10, 2012)

dmxtothemax said:


> Do you know for sure what the current draw is for the new unit ?
> If for instance the new unit needs 2 amps,
> and your transformer is rated for 1 amp,
> then this would explain the burn outs !
> ...


Appreciate the responses.

I'm going to show my newbie experience.

'Putting an amp meter on the tranny'
So i assume since i have already shown that the transformer was showing ~24v when it was good, i need to measure something else. I have only the 2 lines coming into the transformer, so i need to measure those two? What am i looking for?

Thanks


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## COLDIRON (Mar 15, 2009)

Make sure the VA reading on the transformer is the same as the original.


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## dmxtothemax (Oct 26, 2010)

Use your multi meter, set to "AC AMPS"
Usually this involves moving the red lead to a different socket
on the multi meter,
as well as a different position for the switch.
Take one wire off the tranny,
connect one of the multi meter leads to the tranny, 
the other lead of the meter goes to the wire that was
connectted to the tranny.
The meter should now be in "SERIES" with the load.
Double check that the switch is correct on the meter
and that the leads are in the correct socket to measure amps.

Now turn the system on !
What current is flowing during operation ?
and what current flows when not in use ?

Report your findings !


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## heynowjerry (Nov 10, 2012)

dmxtothemax said:


> Use your multi meter, set to "AC AMPS"
> Usually this involves moving the red lead to a different socket
> on the multi meter,
> as well as a different position for the switch.
> ...


Reporting my findings. My multimeter only handles DC Amps, so i need to get a better unit that handles AC Amps.


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## COLDIRON (Mar 15, 2009)

This is a recording did you check the VA rating on the transformer to make sure it's the same as the original?? Got to have the right parts before testing. 1 step at a time.


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