TM 9-6115-664-13&P
5-16. ALTERNATOR MAINTENANCE
5.
Test for battery voltage as follows. Replace alternator if battery voltage is not present:
a.
Connect multimeter red lead to regulator connector pin E. Connect multimeter black lead to alternator ground
bolt. Battery voltage shall be present.
b.
Connect multimeter red lead to the alternator B+ output stud. Connect multimeter black lead to regulator
connector pin A. Battery voltage shall be present.
c.
Connect multimeter red lead to regulator connector pin B. Connect multimeter black lead to alternator ground
bolt. Battery voltage shall be present.
6.
Connect test cable #3 (white cable with regulator connectors and alligator clip) between regulator connector and
regulator.
WARNING
Do not ground alligator clip. Injury to personnel and damage to equipment could
result.
7.
Connect multimeter red lead to test cable #3 alligator clip. Connect multimeter black lead to alternator ground bolt.
Voltage reading shall be less than 1.0 volt. If voltage is greater than 1.0 volt, regulator is defective and must be
replaced. Leave multimeter connected.
8.
Disconnect test cable #2 alligator clip from the alternator B+ output stud. Multimeter will now read battery voltage.
If voltage reading at pin C is below battery voltage, regulator is defective and must be replaced.
9.
If additional testing is required, proceed as follows:
WARNING
Use caution when testing alternator magnetic pull. There will be a spark when
alligator clip contacts ground bolt. Steel tool will "jump" from hand and snap
against alternator. Do not hold hand between tool and alternator.
a.
With test cable #3 still connected between regulator connector and regulator, connect test cable #3 alligator clip to
alternator ground bolt. There will be a large spark at the point of connection, indicating that the field coil is
conducting.
b.
Place a steel tool next to the alternator fan hub (a thin piece of steel will work as well). If the tool snaps against
the hub, the alternator coil is good and will produce electricity. Replace the regulator.
c.
If tool is not attracted to alternator hub, the field coil is defective. Replace the alternator.
10.
Disconnect all test cables. Install fuel module cover and close top rear lid.
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