1. Connect the multimeter to two
pairs of stator leads. Use a multimeter
a. Inspect brush assembly (29, figure
and set to the lowest range scale on the
8-2) for excessive wear, replace brush
assembly if 3/16 of an inch or less extends
(infinite) the stator winding is open.
beyond bottom of holder.
2. To test the stator for grounds,
b. Check brush assembly (29) spring
tension with suitable spring scale. Spring
to the ground screw or the shell, and note
tension should be 4 to 6 ounces.
the reading. Then reverse the multimeter
lead connections, and note the reading. If
c. Test rectifier diodes (37 and 38) in
both readings are very low, the stator is
heat sinks connecting one of multimeter
leads to the heat sink and the other multim-
f. Test rotor assembly (51) or grounded
eter lead to the diode stem, and note the
reading. Then reverse the multimeter lead
slip ring, using a multimeter. No circuit
connections, and note the reading. If both
from either slip ring to shaft is correct
readings are very low, of if both readings
are very high, the diode is defective. A
good diode will give one low reading and one
assembly (51) windings using a multimeter.
d. Test isolation diode assembly (22)
by connecting one of the multimeter test
h. Test voltage regulator (25) by con-
leads to the output terminal stud of the
necting multimeter leads to regulator leads
diode, the other to the exposed metal area
on heat sink, and note reading. Then re-
1. Multimeter lead (+) to regulator
verse the lead connections and note the
reading. If both readings are very low, or
lead yellow, multimeter lead (-) to regula-
if both readings are very high, the diode is
tor lead red. Multimeter should indicate
defective. A good diode will give one low
300 to 350 ohms.
reading and one high reading.
2. Multimeter lead (+) to regulator
e. Test stator assembly (39) for grounds
lead red, multimeter lead (-) to regulator
and opens as follows:
lead yellow, multimeter should indicate
3. If above readings are not obtained,
These tests may be made with the
stator leads disconnected from the
diodes, or with the stator leads con-
i. Inspect fan (43) for cracked or broken
nected to the diodes provided all the
fins. Check fan bore for wear.
diodes are in good condition. Scrape
enough insulation from the leads to
j . Inspect pulley (42) for worn drive
insure good contact with the test
surfaces and condition of key groove. Check
pulley bore for wear.