TM 5-3800-205-23-2
ELECTRICAL GENERAL MAINTENANCE INSTRUCTIONS - CONTINUED
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ELECTRICAL GROUND POINTS
Many electrical problems are the result of poor ground connections. Ensure that ground connections are good by per-
forming the following steps:
WARNING
Although battery disconnect switch must be ON to test electrical circuit voltage, turn battery disconnect
switch to OFF before performing resistance tests or replacing parts. Failure to follow this warning may
result in injury to personnel and damage to parts or equipment.
a.
Remove screw, lockwasher, nut, etc. connecting ground wire terminal to machine ground point.
b.
If necessary, clean mounting hardware, wire terminal, and ground point with detergent and a scrub brush.
c.
Remove any rust or corrosion from ground point with a wire brush and abrasive cloth.
d.
Replace defective mounting hardware and wire terminal as necessary.
e.
Install wire terminal to ground point with screw, lockwasher, nut, etc. and tighten securely.
MULTIMETER USAGE
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 voltmeter scale is used to test voltage levels 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 con-
nector or electrical wiring).
NOTE
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.
CAUTION
Before performing a continuity test, always place battery disconnect switch in OFF position and disconnect
circuit to be tested. Failure to follow this caution may damage multimeter.
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 has continuity.
(b) If readout indicates resistance, circuit is open.
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