Problem: The doorbell doesn’t
ring at all, works only occasionally, or rings
Background: In most all cases the doorbell will be powered
with low voltage, fed from a transformer that converts
120-volt household current to the 6- to 8-volt range for
older systems, or to a 12- to 14-volt range for newer
systems. The low-voltage power supply wire is interrupted
by the push button switch at the door. When the button is
pushed, the power is fed through to the bell. Weather can
corrode outdoor switch contacts, and vibration can loosen
connections at the bell.
What to do: Possible causes for the failure include
a faulty switch, wiring, transformer, or the bell itself.
Chances are best that the switch may be bad, so start
there. Unscrew the push button and check to see that the
wires are making good contact under the 2 screws behind
the switch. If the connections are good, touch a
screwdriver between the 2 screws or remove the 2 wires and
touch them together. (Normally low-voltage wiring does not
carry enough cur rent to be dangerous except at the
transformer.) If the doorbell rings, the problem is the
pushbutton. Clean its terminals with sandpaper or
electrical contact cleaner. If that doesn’t work, replace
it; replacements are low cost and readily available.
If, when the wires are touched together, the bell doesn’t
ring but the transformer hums, suspect a wiring defect or
the bell itself. If the transformer doesn’t hum, suspect
defective wiring or a burned-out transformer. Check all
wires from the transformer to the push button and back to
the bell, making sure connections are good. Inside some
bells you may be able to clean the contact breaker points
with fine sandpaper or emery cloth. The gong should touch
the bell when the con tact points are closed; if not, bend
the hammer slightly.
Special advice: If the transformer is suspected, be
sure to turn off the master electrical switch before
disconnecting because the wires feeding the transformer
will be 120 volts. If you are not positive the transformer
is bad, have it tested at an electrical supply dealer
before buying a re placement.
Helpful hint: To
assure your safety in case the transformer has gone bad
and is not reducing power to low voltage, use a tester and
touch its leads to the 2 screws on the push button switch.
A 120-volt tester will not light up if the transformer is
reducing the power to low voltage.