Piper Navajo Chieftain PA-31-350 Service Manual page 860

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XIV-V. TROUBLESHOOTING CHART
(PROPELLER DEICER SYSTEM) (cont.)
Cause
Trouble
Remedy
Ammeter does not
"flick" approxi-
mately every 30
seconds.
Timer ground open.
Disconnect harness at
timer and check with
ohmmeter from Pin G (of
harness) to ground. If no
circuit, fix open per
schematic diagram.
Timer contacts are
welded (caused by
short circuit in
system.
Test timer as in paragraph
14-59. If timer does not
cycle with voltage at Pin
B, replace timer but be
sure short causing original
failure has been located
and corrected.
Ammeter flicks
between 30 second
phase periods.
Loose connection
between aircraft
power supply and
timer input.
If trouble occurs over
entire cycle, trace wiring
from power source to timer
input to locate and tighten
loose connection.
Loose or poor
connection timer
to deicers.
If trouble occurs in part
of cycle, find which
deicers are affected and
check for rough or dirty
slip rings causing brush
to "skip". If not this,
trace circuits to locate
and fix loose or poor
connection. (If all deicers
on one propeller are
affected, check the ground
circuit.) Flex deicer
straps for break in
deicer straps.
ACCESSORIES AND UTILITIES
Reissued: 9/23/80
4 F16