TM 10-3930-641-34-1
ALTERNATOR TESTING (CONT)
(Sheet 2 of 4)
LOCATION/ITEM
ACTION
REMARKS
ELECTRICAL TESTS
1. Diodes
Check all six diodes by attaching a
If both readings are the same the diode is bad. A good
multimeter (set on low scale on ohmmeter)
diode will give one high and one low reading. Replace
to diode lead and diode case. Then reverse
diodes using an arbor press.
leads and note meter reading.
2. Field coil (check for ground)
Connect multimeter to coil frame (ground)
If meter reading is low the coil is grounded. Replace.
and one lead.
See page 3-176
3. Field coil (check for open)
Connect multimeter to the coil leads.
If the meter reading is high, the coil is open. Replace.
See page 3-176
4. Stator (check for ground)
While one multimeter lead is kept on the
If the meter reading is low in any of the 3 test
frame move the other lead to three stator
windings the stator is grounded. Replace.
leads and note the 3 readings.
5. Stator (check for open)
Successively connect between each pair of
If meter reading is high the stator windings are open.
stator leads with the multimeter.
Replace. See page 3-176
Go on to Sheet 3
3-184
