Cessna T188C - Page 309

MODEL 188 & T188 SERIES SERVICE MANUAL
16-10. TROUBLE SHOOTING. (Cont.)
TROUBLE PROBABLE CAUSE REMEDY
BATTERY
WILL NOT SUPPLY
Faulty contactor or wiring.
3. Measure voltage
at master
POWER TO BUS
OR IS INCAP-
between
contactor and
master
switch terminal
(smallest)
on
ABLE
OF CRANKING
ENGINE
switch.
contactor with
master switch
(Cont.)
closed.
Normal
indication is
zero volts. If voltage reads
zero, proceed to step 4. If a
voltage reading is obtained,
check wiring between contactor
and master switch. Also check
master switch.
Open coil on contactor. 4. Check continuity between
"BAT" terminal and master
switch terminal of contactor.
Normal indication on 14 volt
aircraft is 16-24 ohms. Nor-
mal indication on 28 volt air-
craft is 50-70 ohms. If ohm-
meter indicates an open coil,
replace
contactor.
If
ohm-
meter indicates a good coil,
proceed
to step
5.
Faulty contactor contacts. 5. Check voltage on "BUS"
side of contactor with master
switch
closed.
Meter
nor-
mally
indicates
battery
voltage.,
If voltage
is zero
or intermit-
tent, replace contactor. If
voltage is normal, proceed to
step 6.
Faulty
wiring between con-
6. Inspect
wiring between
con-
tactor and bus. tactor and bus. Repair or
replace
wiring.
16-11. REMOVAL
AND
INSTALLATION
(See
b.
T188C THRU
T18803721T
figure 16-2.)
1. Remove cover on
right hand side of tailcone
a. A188B
THRU
18803721
for
access to
battery.
1. Remove cover
on right hand side of fuselage
2. Remove
battery box cover.
at the wing
leading edge
for access to battery.
3. Disconnect
the ground
cable from
the nega-
2. Remove battery
box cover,
tive
battery terminaL
3. Disconnect the ground cable from the nega-
tive battery terminal CA UTION1
iCAUTIONI
When installing or
removing the battery
always observe
the
proper polarity
with
When installing
or
removing
the battery
the
aircraft electrical
system (negative
always observe the
proper polarity with
to ground). Reversing
the polarity, even
the aircraft electrical
system
(negative
momentarily,
may result
in failure
of
to ground).
Reversing the
polarity, even
semiconductor
devices
(alternator
diodes,
momentarily,
may result
in failure of
radio protection
diode
and radio transistors).
semiconductor devices (alternator diodes.
radio protection
diode and
radio transistors).
4. Disconnect
the cable
from the positive
termi-
nal of the battery.
4. Disconnect the cable from
the positive termi-
5. Lift the battery out
of the battery box.
nal of the battery.
6. Reverse
the preceding
steps for reinstalla-
5. Lift the battery out of the battery box. tion.
6. Reverse
the preceding
steps for
reinstalla-
tion.
16-5