out of the end frame Also use a suitable tool which
To check for opens, connect a test lamp, or an
fits over the outer diode edge to push the diode in.
ohmmeter to the two field coi1 leads as shown. If
and support the heat sink or end frame with a suit-
the lamp fails to light. or if ohmmeter reading is
a b l e tool. NOTE: Diode replacement tools are
high (Infinite), the field coi1 is open.
available from various manufacturers normally sup-
plying tools and test equipment to the automotive
The winding is checked for short-circuits by con-
Industry. CAUTION: Do not strike the diode, as
necting a battery and ammeter in series with the
the shock may damage it and the other diodes. Use
field coil. Note the ammeter reading and refer to
only those diodes listed in the parts list for these
Delco-Remy Service Bulletin 1G-187 for specifi-
units. Never use substitutes.
cations. An ammeter reading above the specified
v a l u e indicates shorted windings. An alternate
method is to check the resistance of the field by
connecting an ohmmeter to the field coil. If the re-
sistance reading is below the specified value, the
STATOR CHECKS (Figure 7)
winding is shorted The specified resistance value
(Omit for overcharged battery)
can be determined by dividing the voltage by the
current given in Bulletin 1G-187
The stator windings may be checked with a 110-
volt test lamp or an ohmmeter. If the lamp lights, or
To replace the field coil. separate drive end frame
if the meter reading IS low when connected from
from rectifier end frame, remove field coil attach-
a n y stator lead to the frame, the windings are
ing screws and pull leads and grommet through end
grounded. If the lamp fails to light, or if the meter
f r a m e hole. Place grease on grommet and pull
reading is high when successively connected be-
grommet into hole during assembly.
tween each pair of stator leads, the windings are
open.
DIODE CHECKS (Figure 7)
( O m i t for overcharged battery)
A short circuit in the stator windings is difficult
to locate without laboratory test equipment due to
Check each of the six diodes by removing each
the low resistance of the windings. However, if all
diode lead from the stud and connecting an ohm-
other electrical checks are normal and the genera-
meter using the lowest range scale to the diode
t o r fails to supply rated output, shorted stator
l e a d and case. Then reverse the ohmmeter lead
windings are Indicated
c o n n e c t i o n s lo the diode lead and case If both
readings are the same, replace the diode A good
diode will give one high and one low reading
To replace the stator. separate drive end frame
CAUTION: Do not use high voltage such as 10
from rectifier end frame, and pull leads and grom-
volt test lamps, to check diodes.
met through hole. Place grease on grommet and
pull into hole during assembly.
Before replacing a diode in the rectifier end
frame, the end frame must be separated from the
drive end frame. Also, before replacing a diode in
REGULATOR REPLACEMENT (Figure 7)
the heat sink or end frame, it is necessary to remove
the heat sink from the end frame by detaching from
After disconnecting the three identically colored
the heat sink the regulator lead, the heat sink mount-
regulator leads, the regulator may be replaced by
ing screws, a n d the generator output terminal.
removing the attaching screws and disconnecting
Note the round Insulators under the heat sink mount-
the regulator lead from the heat sink.
ing screws, and the flat insulator located behind
the heat sink. The silicone grease on both sides
of the flat Insulator provides the necessary heat
transfer between heat sink and end frame. Reapply
silicone grease during assembly, tighten the heat
BEARING REPLACEMENT
sink mounting screws loosely, securely tighten the
A N D LUBRICATION
output terminal, then securely tighten the heat sink
screws.
The bearings normally will operate between en-
gine overhaul periods without attention. At time
of engine overhaul, the bearings and seals should
To replace a diode in the heat sink, support the
be replaced, and a fresh supply of lubricant added
heat sink, and use an arbor press or vise to push
to the reservoirs.
the diode out. Use a suitable tool to pull the diode
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