Cessna 177 SERIES Service Manual page 276

16-48 TROUBLE SHOOTING (Conti.
*
~TROUBLE
PROBABLE CAUSE REMEDY
CAUTION
Extreme care should be taken when exchanging flash tube. The tube
is fragile and can easly be cracked in a place where it will not be
obvious visually. Make sure the tube is seated properly on the base
of the nav light assembly and is centered in the dome.
NOTE
When checking defective power supply and flash tube, units from
opposite wing may be used. Be sure power leads are protected
properly when unit is removed to prevent short circuit.
ONE ANTI-COLLISION Desfecive Strobe Power Supply,
1. Connect voltmeter to red lead be-
STROBE LIGHT WILL or flash tube.
tween aircraft power supply (battery/
NOT LIGHT. (1973 MODELS
external power) and strobe power sup-
& NO.
ply, connecting negative lead to wing
structure. Check for 12 volts thru
1977 models, and 24 volts beginning
with 1878 models. If OK proceed to
step 2. If not, check aircraft power
supply (battery/external power).
2. Replace flash tube with known
good flash tube. If system still
does not work, replace strobe
power supply.
DOME LIGHT TROUBLE.
Short circuit in wiring. 1. Inspect circuit breaker. If
circuit breaker is open, proceed
to step 2. If circuit breaker is
OK, proceed to step 3.
Defective wiring. 2. Test circuit until short is
located: 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.
Lamp burned out 4 Test lamp with ohmeter or
new lamp. Replace lamp.
Defective switch. 5. Check for voltage at dome
light with master and dome light
switch on Should read battery
voltage. Replace switch.
INSTRUMENT LIGHTS WILL Short circuit in wiring
1. Inspect circuit breaker. If
NOT LIGHT (THRU 1974
circuit breaker is open, proceed
MODELS.
to step 2. If circuit breaker is
OK, proceed to step 3.
Change 7 16-16A,116-16 blank)