Plz school me on vintage doorbell wiring


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Old 12-11-13, 11:16 AM
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Plz school me on vintage doorbell wiring

So my Mom calls and tells me her doorbell is out. Her house was built in the late 1970s and the doorbell is one of those that uses electromagnets to activate the klangers. It goes 'ding-dong' when you press the front doorbell and just 'ding' when you press either of the other two. Or at least it was supposed to. The problem, she tells me, is that the neither of the 'ding'-only buttons -- one on the back door and one on the carport -- is working.

The first thing I notice is that the lights in the buttons have burned out on two of the three, and they're all original equipment, so I run to Home depot for three new ones. After switching to the new button, the front doorbell ding-dongs as advertised. The problem comes when I replace the buttons on the single ding doors, the ones on the back door and the carport.

It doesn't matter how I hook up the buttons, in series or in parallel, it energizes the electromagnet on the dinger in the doorbell and keeps it captured. I didn't notice until I pulled the cover off the klanger assembly, you can see the klanger remains extended against the brass chime, and you can hear a faint buzzing. So for some reason, the dinger's electromagnet is energized, and remains that way, even though no one is pressing any buttons.

If I only wire either button by itself, it works normally, provided I twist together the wires for the missing button. But if I hook up the buttons at both locations, even if I re-use original 30+ year old buttons, the dinger gets energised and remains so.

So then I start interrogating Mom. Come to find out, she installed the doorbell button on the back door herself, using instructions from a telephone company man she knew from church. All she did was splice into the wires running to the carport door's button. But she is adamant that both the button on the carport and the back door had worked, for many years.

So at this point I'm looking at two possibilities. The first is that Mom is a better electricitan than I am, and it's beyond me to duplicate her original wiring. The second is that something has failed in the doorbell mechanism itself, or maybe the transformer (which is buried who knows where in the attic).

Any ideas what the cause might be, or how I might fix it?


On a related topic, how is it the light in the doorbell button illuminates without completing the circuit and activating the doorbell? Does it somehow ground through the wall?
 
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Old 12-11-13, 11:38 AM
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There are times when I don't try to figure out a circuit. I just abandon and run new. Are there only two places on the chime to connect buttons. If so the back and car port should be paralleled and connected to the back door terminal. I would use unlighted door buttons for these. It is the high impedance of the lights that keep them from energizing the chime but in parallel that impedance is reduced, maybe enough to cause the door chime coil to hum. Not full voltage but enough.
 
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Old 12-11-13, 01:01 PM
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Vintage doorbell wiring is the same as modern doorbell wiring.

The lighted button uses the bell chime assembly itself to complete the circuit for the little light.

Perhaps two buttons (with two little light bulbs) let enough current through to keep the plunger extended against the bell or chime. You'll have to substitute an unlighted button for at least one of the locations that ring the "back door" chime.

You said you tried various wiring combinations. With some combinations including the correct combination (buttons in parallel with each other), twisting together the two wires that normally go to a button will also keep the plunger extended against the chime.

The button should go dark at the moment it is pushed. Touching the two wires that go to a button together (or bridging the two button terminal screws) should ring the bell. With the buttons connected inseries relative to each other (incorrect) both buttons have to be pushed at the same time to ring the bell. Too high a transformer voltage with a lighted button may cause the plunger to be kept extended and will also shorten the life of the button light.
 
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Old 12-11-13, 03:14 PM
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Try removing the buttons and just touch the wires together. See if the plunger still sticks.
If touching the wires gets you constant working dings, you'll know its the buttons.
 
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Old 12-11-13, 03:27 PM
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Just so you know vintage door bell wiring used zinc carbon dry cell batteries that were two inches in diameter and four inches high with screw and nut terminals on top. 4-8 batteries in series was used. The wiring was often cloth wrapped enameled copper wire.

Fun fact: The same type of batteries were used in the old crank wall telephones to power the carbon microphone.
 
 

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