Mooney M20M - Page 142

SERVICE AND
MAINTENANCE MANUAL
M20M
MOONEY
AIRCRAFT
CORPORATION
3061-02
TROUBLE
SHOOTING
CHART- ELECTRIC PROPELLER
DE-ICE
TROUBLE
PROBABLE
CAUSE
REMEDY
Buss load
meter/ammeter
No
power
from
aircraft.
If
no
voltage
into
circuit
breaker,
locate
shows
0
current
all
phases
of and
correct
open.
the
timer
cycle.
Tripped
circuit breaker. Locate
and
correct
short
before
resetting
circuit
breaker.
Circuit breaker
or
switch
faulty.
If
no
voltage
at
circuit
breaker
output
with
voltage
at
input
and circuit
breaker
does
not
reset,
replace
circuit
breaker.
If
voltage
is
OK
at
output,
check
switch
in
same
manner.
Open
Buss load
meter/ammeter
Disconnect harness
at
timer
and
check
to
timer.
for
voltage
at
hamess
Terminal
B
to
ground.
if
none,
locate
and
correct
open.
Open
timer
to
brush
assembly.
Disconnect wire
hamess
at
brush
assembly
and check
voltage
to
ground
from leads.
(See de-icing
system
wiring
schematic
for
power
and
ground
lead
and
pin
identification.)
If
low
or
no
voltage,
locate and
correct
open
or
high
resistance
in wire
hamess.
Check
continuity
from
Terminal
G,
or
lead
to
ground;
if
high
resistance
is
indicated,
check
ground
wire
for
breakage
and
ground
connections
for
correctness
and
tightness.
Correct
as
required.
Open
in
De-leer,
De-leer
wire
Disconnect
De-leer
leads and
check
harness
or
slip
ring
assembly
resistance
per
manufacturer’s
service
leads.
data.
If
not
OK,
replace
faulty
De-leer
boot.
If
OK,
check
for
land
repair)
open
in
de-ice boot
wiring
hamess
leads.
Ohmmeter
needle
must not
flicker
when
leads
are
stretched
or
flexed.
Replace
as
required.
Open
on
both
ground
brushes. Remove
brush block
assembly
and
check
both
ground
brushes
for
continuity
between
the
brush
and
pigtail
lead.
If
an
open
is
found,
repair
brush
block
assembly.
If
OK,
reinstall
and
check
for
proper
face
alignment
and
brush
proiection
per
manufacturer’s
Service
Data.
Buss load
meterlammeter
Open
in
wiring
between timer
See
"Open
Timer
to
Brush
Assembly"
shows normal
current
part
of
and brush
block
assembly.
above.
cycle,
zero
current
rest
of
cycle.
Open
in
De-leer
or
de-ice boot
See
"Open
in
De-leer" above.
wire
harness.
4-99
30-61
-02
17
OLDWILLWAYNE