Cessna T188C - Page 327

MODEL 188
& T188 SERIES
SERVICE
MANUAL
16-33. TROUBLE
SHOOTING THE ALTERNATOR
SYSTEM (14 VOLT
SYSTEM)( Cont.)
TROUBLE PROBABLE CAUSE REMEDY
ALTERNATOR SYSTEM
Regulator faulty
or improp- 2.
Stop engine, remove cowl,
WILL NOT KEEP BAT-
erly adjusted. (Cont.)
and remove
cover from voltage
TERY CHARGED (Cont).
regulator.
Turn master switch
ON/OFF
several
times
and ob-
serve field relay in regulator.
Relay should open and close with
master switch and small arc
should be seen as contacts open.
If relay
is inoperative,
proceed
to step 3. If relay operates,
proceed to step 4.
3. Check voltage at "S" terminal
of
regulator
with master
switch
closed. Meter should indicate bus
voltage.
If voltage
is present,
re-
place regulator.
If voltage
is not
present,
check
wiring
between
CAUTION regulator and bus.
Before performing step 4, remove radios from the panel. 4. Remove plug from regulator
and start engine. Momentarily
jumper the "A+" and "F" termi-
nals together on the plug. Ship's
ammeter should show heavy rate,
of charge. If heavy charge rate
is observed, replace regulator.
If heavy charge rate is not ob-
served,
proceed
to step
5.
Faulty wiring between alter- 5. Check resistance from "F"
nator and
regulator,
or
terminal
of regulator
to "F"
ter-
faulty alternator.
minal of alternator.
Normal
indication is a very low resis-
tance. If reading indicates no,
or poor continuity, repair or
replace wiring from regulator
to alternator.
6. Check resistance from "F"
terminal of alternator to alter-
nator case. Normal indication
is 6-7 ohms. If resistance is
high or
low. repair
or replace
alternator.
7. Check resistance from case
of alternator
to airframe
ground.
Normal indication is very low
resistance. If reading indicates
no, or
poor continuity,
repair or
replace
alternator
ground
wiring.
16-23