16
Should it be determined that the cord is not the source of the
problem, the appliance may need to be disassembled in order
to pinpoint the problem. Refer to the owners manual of the
appliance. The manufacturer of the appliance may require that
the appliance be serviced only by a qualified repair technician.
7.3 Fuses
Note: With the power OFF, always remove a fuse from its
socket before testing it. With cartridge fuses, touch the test
leads to each end of the fuse (see fig. 10). If the fuse is good,
the needle indicator will move to -0- ohms, or if the continuity
buzzer is being used it should sound. If not, replace the fuse.
On plug-type fuses, touch the the test leads on the bottom
contact and the other on the threaded metal contact (see fig.
11). On time-delay/tamper-proof fuses, the other metal contact
is at the top of the ceramic threads.
7.4 Switches
Cut off the power source to the switch. If necessary, remove
the switch from whatever it’s mounted to. Turn the switch to
the ON position and touch the test leads to the switches
terminals (see fig. 12). If the switch is good, the needle
indicator will move to -0- ohms, or if the continuity buzzer is
being used it should sound. If not, replace the switch. On
other than two-way SPST (single pole, single throw)
switches such as three-way light switches or double pole
double throw (ON-OFF-ON) switches, in each ON position
you will need to alternate the test leads between the
switches terminals to determine which two terminals control
that ON position.
15
Common Resistance and
Continuity Measurements
Continuity tests are probably the most frequently performed
electrical troubleshooting procedures around the home.
ALWAYS REMEMBER THAT CONTINUITY CHECKS ARE
TO BE MADE WITH THE POWER TO THE CIRCUIT
TURNED OFF. Polarity of the test leads is not a factor in
making continuity checks.
7.1 Extension Cords
Unplug the cord. Set the function/range switch to the Rx1K
position. Touch one of the test leads to one of the metal prong
ends of the cord, and insert the other test lead in either one of
the receptacle slots on the other end of the cord, making sure
the test lead is making good contact with the receptacle (see
fig. 9). If the needle indicator does not move to -0- ohms, or if
the continuity buzzer is being used and does not sound, insert
the test lead into the other receptacle slot, again making sure
of good contact. If the needle indicator does not move to -0-
ohms, or if the continuity buzzer is being used and does not
sound, the cord should be replaced.
7.2 Appliance Cords
Unplug the appliance from its power source. Turn its power
switch to the ON position. Touch the test leads to the metal
prong ends of the cord. The tester should indicate a low
resistance value. If not, flex the cord while the leads are still in
contact with the metal prongs. If the needle indicator moves
sporadically, or if the continuity buzzer does not sound, while
the cord flexes, there may be a broken conductor in the cord.
If the needle indicator does not move at all, or the buzzer does
not sound, there may be an open circuit in the appliance.
Figure 11Figure 10
Figure 9
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