Extension Cords; Fuses; Switches - GB Intsruments GMT-319 Manual Del Propietário

GMT-319 manual 7.08.qxp
value of the reading on the green ohms scale
and multiply the reading by 1000 in the X1K/10
in X10/1 in X1 position. If you're making basic
continuity tests, the needle indicator should
move all the way to the right side of the ohms
scale if continuity exists.
Note: When switching the unit back and forth
from ohms to other functions, always zero the
needle indicator before taking another reading.
Failure to zero the needle before taking
resistance/continuity measurements will result in
inaccurate readings.
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 Rx1 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. 4). If the needle
indicator does not move to -0- ohms, insert the
Figure 4
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test lead into the other receptacle slot, again
making sure of good contact. If the needle
indicator still does not move the cord has a break
and should be replaced.

7.2 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. 5). If the fuse is good,
the needle indicator will move to -0- ohms. 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. 6).
Figure 5

7.3 Switches

Cut off the power source to the switch. If
necessary, remove the switch. Turn the switch to
the ON position and touch the test leads to the
switch terminals (see fig. 7). If the switch is
good, the needle indicator will move to -0-
ohms. If not, replace the switch. On other
switches such as three-way light switches or
double pole double throw (ON-OFF-ON)
switches, each ON position will need to be
tested. Alternate the test leads between the
Figure 7
Figure 6
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