Trouble Shooting The Alternator System - Cessna 177 SERIES Service Manual

g16-39. TROUBLE SHOOTING THE ALTERNATOR SYSTEM (THRU 1977 MODELS) (CONT.)
TROUBLE
PROBABLE CAUSE
REMEDY
OVER-VOLTAGE WARNING
Regulator faulty or improperly
1. With engine running turn off
LIGHT ON. adjusted.
Faulty sensor switch.
and on battery portion of the
master switch. If the light stays
on shut down engine then turn on
the "BAT" and "ALT" portion
the master switch.
Check for
voltage at the "S" terminal of the
voltage regulator.
If voltage is
present adjust or replace regula-
tor.
If voltage is not present
check master switch and wiring
for short or open condition.
If
wiring and switch are normal
replace sensor.
16-39A.
TROUBLE SHOOTING THE ALTERNATOR SYSTEM. (BEGINNING WITH 1978 MODELS)
a.
ENGINE NOT RUNNING.
TROUBLE
PROBABLE CAUSE
REMEDY
AMMETER INDICATES HEAVY
Shorted diode in alternator.
Turn off Battery Switch and re-
DISCHARGE OR ALTERNATOR
move "B" Lead from alternator.
CIRCUIT BREAKER OPENS.
Check resistance from "B"
(Battery Switch ON,
Terminal of alternator to alter-
Alternator Switch OFF,
nator case. Reverse leads and
all other electrical
check again.
Resistance reading
switches OFF.)
may show continuity in one direc-
tion but should show an infinite
reading in the other direction.
If an infinite reading is not ob-
tained in at least one direction,
repair or replace alternator.
ALTERNATOR REGULATOR
Short in Over-Voltage
Disconnect Over-Voltage Sensor
CIRCUIT BREAKER OPENS
sensor.
plug and recheck.
If circuit
WHEN BATTERY AND
breaker stays in replace Over-
ALTERNATOR SWITCHES
Voltage Sensor.
ARE TURNED ON.
Short in alternator voltage
Disconnect regulator plug and
regulator.
recheck.
If circuit breaker
stays in, replace regulator.
Short in alternator field.
Disconnect "F" terminal wire
and recheck.
If circuit breaker
stays in, replace alternator.
16-12
Change 7