TM 5-3805-292-23
0173
MULTIMETER USAGE
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1. General. A multimeter is used to troubleshoot the electrical system of the machine. The multimeter Ohms
scale is used to test for continuity, shorts, and resistance. The multimeter Volt scale is used to test voltage lev-
els at any point in the electrical system.
2. Continuity Tests. Continuity tests are performed to check for breaks in a circuit (such as a fuse, switch, light
bulb connector, or electrical wiring).
N OT E
If readout will not zero properly, replace batteries and repeat zeroing procedure. If readout
will not zero after batteries have been replaced, notify your supervisor.
a. Zero Multimeter.
(1) Set multimeter to ON.
(2) Select OHMS.
(3) Select LOWEST VOLTAGE/OHMS scale.
(4) Touch black and red probes together and check for a zero indication on digital readout.
b. Testing for Continuity.
(1) Zero multimeter.
(2) Connect black and red probes to both terminals of circuit being tested.
(3) Observe readout and interpret results as follows:
(a) If readout indicates 0 (zero), circuit is open.
(b) If readout indicates resistance, circuit has continuity.
c.
Testing for Shorts. A short (or short circuit) occurs when two circuits that should not be connected have
metal-to-metal contact with each other. A short also occurs when a circuit that should not touch ground
has metal-to-metal contact with ground.
(1) Zero multimeter.
(2) Connect black probe to one pin and red probe to either ground or another pin.
(3) Observe readout and interpret results as follows:
(a) If readout indicates 0 (zero), circuits are not shorted.
(b) If readout indicates resistance, circuits are shorted or circuit is grounded, if testing to ground.
(c) If readout jumps or flickers, circuits are shorted or grounded intermittently.
d. Testing for Resistance. Allowable resistance readings depend on circuit being tested. Refer to the
troubleshooting section.
(1) Zero multimeter.
(2) Select OHMS.
(3) Select LOWEST VOLTAGE/OHMS range. If test specifies Ohms range, select required range.
(4) Connect black and red probes across circuit to be tested.
(5) Observe readout as circuit resistance.
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