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captainron19 02-17-2010 08:17 AM

Doorbell Question
I have a question regarding a doorbell. Yesterday I noticed that the light was out on button and then realized the doorbell was not working at all. I checked all breakers (nothing tripped).

I then removed doorbell button and checked both wires - seemed ok. I removed wires from their terminals on the button and made contact between the two and still nothing rang.

I am just using the front of my chimer so inside the doorbell unit I have 1 red wire going to "trans", 1 red wire going to "front" and a pair of twisted white wires. The problem is, I do not have a volt meter.

Is there anything I can with the wires in the unit to assure I am getting poiwer to it to come to the conclusion if it is the chimer that is bad or if I lost power to the unit?

plummen 02-17-2010 09:15 AM

find the transformer to make sure youre getting voltage to doorbell

hyunelan2 02-17-2010 09:22 AM

I'll take a stab at this. Most doorbell units run on 12v-24v DC, the button just completes the circuit and the chime sounds. If you have multiple doorbells (front and rear) is the other one working? There are 4 possible problems:

1. Bad button/connection on button - you ruled this out
2. Bad chime or connection to chime
3. Break in wire
4. Bad transformer or connection on the transformer.

Here is a quick schematic I pulled from the internet:

I found that picture here:

I would probably start by using a meter or test-lamp (commonly used in automotive) to see if the + and - on the DC side of the the transformer is indeed putting power out. If it is, you know your problem is either with the wiring or the chime. Since your light on the doorbell was not lit, I would imagine that the problem is either the transformer or the wiring from the transformer to the button.

plummen 02-17-2010 09:35 AM

whats the dc side of transformer? dc is battery power where i come from :wink:

AllanJ 02-17-2010 11:25 AM

The "DC" side (more correctly, secondary) of the transformer generally has two screw terminals where thin wires are attached. The current may or may not be direct depending on whether there are other components inside the transformer unit.

You should buy a voltmeter and learn how to use it. Voltage at a doorbell transformer secondary will be around 24 volts. Now you can take a short length of wire and very briefly connect together (actually create a short circuit at) the secondary terminals and observe a small spark (arc) to verify that the transformer is working. But I do not advise neophytes to do this because if you mistake the primary terminals for secondary terminals, the arc will be big and scary and if you hold it too long you will blow the transformer.

The transformer (its primary) like everything else is connected to one of the branch circuits that is breaker protected. Check all the breakers again to see that none are tripped.

captainron19 02-21-2010 12:55 PM

Just another point - how am I sure if I have the doorbell transformer found. I do have a small transformer mounted on the side of my electrical panel with a white and a red wire coming from its 2 terminals..... but how can I be sure this is for my doorbell? it is a brown wire actually with an insulated red and a white wire inside of it.

At my doorbell on the first floor I have 2 actual sets of wires coming out of the wall at my doorbell - both appear to be brown and contain a white and a red wire inside of each.

AllanJ 02-21-2010 02:56 PM

You probably have found the doorbell transformer.

It is very unlikely for a single home to have more than one transformer of that kind or shape and with the same kind of wires (red and white in a brown jacket).

Still it is a good idea to check it for sure. The formal way of checking is to do voltage and/or continuity checks. If you measure (24 or so) volts across the transformer secondary and also 24 volts across the red and white wires at the doorbell, then turn off the breaker and measure no volts in both of these places then you have found the proper transformer.

Before that you can disconnect one of the wires (red or white) from the transformer and then measure across the two terminals. If you don't get 24 volts across the secondary and the power is on (120 volts across the primary which is probably two black wires connected to neutral and breaker hot respectively inside the panel), then the transformer is not working.

plummen 02-21-2010 03:08 PM

most doorbell transformer i see are 12-18v,hvac transformers are 24v

Itsdanf 02-21-2010 04:51 PM

2 Attachment(s)
Don't they also use similar transformers for thermostats...?

I have two transformers in my current house (photos attached). One is by my front door, and I believe it's for the doorbell (only one bell/button). The other one is in my HVAC closet, and I believe it's for a thermostat....

plummen 02-21-2010 05:54 PM

id check the voltage on each,furnace/ac transformer will be 24v

SULTINI 02-22-2010 07:08 AM

Yes HVAC transformers are 24 volt with a higher VA rating than a door bell transformer.

Why not just go and buy a small cheap electical tester, it would be good to have it around anyway.

Thurman 02-22-2010 07:22 AM

I do "Handyman" (Honey-do's) in my business. I get doorbell calls often. In today's world I can install a "wireless"doorbell, two button, battery operated, system--quicker, easier, more cost efficient, than troubleshooting a conventional wired system. I do find the old transformer, remove the 110v input wiring, cap them off, and identify them before leaving. Just my 2 worth, David

SULTINI 02-22-2010 07:30 AM

I really don't think that's the way to go. There are a lot of old real nice door bells out there that just need parts which are very easy to find and install. If people need new doorbells installed I would recommend wireless but if they already have one just repair it. Especially the ones with the lighted button to see in the dark.

captainron19 03-05-2010 12:48 PM

OK so I picked up a new transformer and put it in today with the help fo a friend of mine who does electrical work (I DO NOT touch inside the panel LOL)

After we hooked up the new transform the doorbell would still not work. But when he put the meter on the doorbell wires it showed power going through when I hit the button outside.

The wierd thing is ... I told him I may have switched wires int he doorbell by accident when i was troubleshooting it. So he started moving the wires around. The white wires we kept twisted together and he moved one of the red wires to "rear" and the other red wire is on "front" so the "tranf" terminal is empty. When we did that every thing worked fine except I dont think the doorbell light is lit but the doorbell works when the button is depressed. Am I missing something? I did not think it would work at all without something connected to the transformer terminal. I do not have a rear door bell in use so its not a big deal but I just wanna make sure everything will be ok

captainron19 03-05-2010 12:53 PM

1 Attachment(s)
Here is a picture of the current configuration working but the doorbell light is not on any more

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