Cessna 177 SERIES Service Manual

16-50.
TROUBLE
SHOOTING
(Cont).
TROUBLE
PROBABLE
CAUSE
REMEDY
INSTRUMENT
LIGHTS
WILL Defective
wiring.
2. Test
circuit until short
is lo-
NOT
LIGHT (THRU
1974
cated.
Repair or replace
wiring.
MODELS).
(Cont.)
3.
Test
for
open
circuit.
Repair
or
replace
wiring.
If no
short
or
open circuit
is
found,
proceed
to
step 4.
Defective
rheostat.
4. Check
voltage
at instrument
light
with
master
switch
on.
Should
read
battery
voltage
with
rheostat
turned
full
clockwise
and
voltage
should
decrease
as
rheostat
is turned
counterclockwise.
If no
voltage
is
present
or voltage
has a
sudden
drop before
rheostat
has
been
turned
full
counterclock-
wise,
replace
rheostat.
Lamp burned
out.
5. Test lamp
with ohmmeter
or
new
lamp.
Replace lamp.
INSTRUMENT
LIGHTS
WILL
Short circuit
wiring.
1. Inspect circuit
breaker.
If
NOT
LIGHT (1975 MODELS
circuit
breaker is open,
proceed
& ON).
to
step 2. If circuit breaker
is
OK,
proceed
to step 3.
Defective
wiring.
2. Test
circuit
until short
is lo-
cated.
Repair
or replace
wiring.
3.
Test for
open
circuit.
Repair
or replace
wiring.
If no
short or
open
circuit
is found,
proceed
to
step 4.
Faulty section
in dimming 4.
Lights will work when control
potentiometer.
is placed
in brighter
position.
Replace
potentiometer.
Faulty light dimming
5.
Test both transistors
with
transistor.
new transistor.
Replace faulty
transistor.
Faulty
selector
switch.
6. Inspect.
Replace
switch.
INSTRUMENT LIGHTS WILL Open resistor or wiring in 1. Test for continuity. Replace
NOT DIM (1975
MODELS & ON). minimum intensity
end of resistor or repair wiring.
potentiometer.
Shorted transistor.
2. Test
transistor by substitution.
Replace
defective
transistor.
Change
6 16-17

Cessna 177 SERIES Specifications

General

Manufacturer	Cessna
Engine Type	Piston
Wingspan	35 ft 6 in (10.82 m)
Seating Capacity	4
Number Built	4, 295
Engine	Lycoming O-360
Horsepower	180 hp
Maximum Takeoff Weight	2, 500 lb (1, 134 kg)