TM 5-2420-231-23-3
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ELECTRICAL GROUND POINTS
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NOTE
To function properly, the electrical system must have good electrical ground points.
Ground points on electrical components and machine frame must be maintained in a
clean and secure condition to minimize electrical problems.
1. Remove nut, locknut, lockwasher, screw, etc., connecting ground wire or ground cable to ground point on
electrical component or threaded stud on machine frame.
2. If necessary, clean dirt from ring terminal, surface of electrical component, ground point, and all mounting
hardware with detergent, water, and a scrub brush.
3. Remove any corrosion or rust with a wire brush and abrasive cloth.
4. Replace defective mounting hardware. Replace any defective ring terminals IAW Ring Terminal Repair in this
work package.
5. Install ground wire or ground cable on ground point with mounting hardware and tighten securely.
END OF TASK
MULTIMETER USAGE
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A digital multimeter is used to test the electrical system of the machine. The digital multimeter continuity/diode
position is used to test diodes and to test a circuit for a short to another circuit or to ground. The Ohms position is
used to measure circuit resistance, thereby testing the integrity of a wire between two points. The AC Volt and DC
Volt positions are used to test voltage levels at any point in the electrical system.
CAUTION
Always test digital multimeter before performing any component tests. Failure to follow
this caution may result in an improper diagnosis and incorrect replacement of parts.
Test Digital Multimeter
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1. Select DC volts and touch digital multimeter leads together. Voltage should be 0V DC.
a. If voltage is more than 0V DC, turn digital multimeter off and inspect leads for cuts, abrasions, and
damage. If leads are OK, replace digital multimeter battery.
b. If voltage is 0V DC, proceed to step 2.
2. Select diode and touch digital multimeter leads together. The diode test alarm should activate and the display
should indicate 0 Ohms.
a. If diode test alarm does not activate or display does not indicate 0 Ohms, calibrate digital multimeter.
b. If diode test alarm activates and display indicates 0 Ohms, digital multimeter is OK. Perform tests using
digital multimeter as directed.
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