Mooney M20K - Page 142

SERVICE
AND
MAINTENANCE
MANUAL
M20K
MOONCIAIRCRAFT
CORPORATION
impressed
in
sequence
to
cycle
power
to
the
propeller
volts
for
S/N
251000
thru
25TBA.
Also
refer
to
B.F.
de-icers.
Each
of
the
pins
should
read
12
volts
in
Goodn’ch,
Report
No.
59-728,
section
4.2.4.
for test
sequence
of
cycle
for
S/N
25-0001
thru
25´•0999
8
24
criten’a.
TIMING
SEQUENCE
TIME
ON
AREAS
OF
PROP
DE~ICERS
HEATED
================================================---===i~====---=;--======I’==
Pin
D
90 sec.
Outboard
Section
)-12VAIC
only
Pin
F
90
sec.
InboardSection
)12VAIConly
Pin
C
90
sec.
Both
Blades
ON
then
OFF
)24V
AIC
only
==============I-==--==---=---====--=======================---==---=========
NOTE
The
timer
does
not
reposition
itself
to
start
at
Pin
D
when
the
system
is
turned
OFF,
but
will
begin
its
cycling
atthe same
position
in
which
is
was
when
last
turned
OFF.
Cycling
will
then
proceed
as
before.
(25-0001
thru
25-0999)
After
a
voltage
reading
of
12
volts
DC
(25-0001
thru
1.
Pin
D
(12V)
of
plug
CTerminal
C
24V)
to
the
25-0999)
is
obtained,
hold
voltmeter
probe
on
the
pin
outboard
tenninal
of
one
prop
boot.
until
the
voltage
drops
to
zero
before
moving
the
probe
2.
Pin
F
of
plug
(12V)
to
outboard
terminal
of
one
to
the
ne>d
pin
in
the
sequence
noted
above.
After
the
propeller
boot
cycling
sequence
has
been etablished,
turn
de-icing
system
switch
OFF
at
the
beginning
of
one
of
the
3.
Pin
F
of
plug
(12V)
CTerminal
G
24V)
to
airframe
"on-time
periods
and
record
the
letter
of the
pin
at
ground.
which
the
voltage
supply
is
present
to
facilitate
4.
Ground
terminal
of
one
prop
boot
to
ground.
performance
of
the
following
test.
(25-0001
thru
25-0999).
30-66-00
BRUSH
TO
SUP
RING
RESISTANCE
TEST
30-64-00
HEAT
TEST
Before
this
test
can
be
performed,
the
jumper
wire
To
check
for
incorrect
resistance
or
the
presence
of
a
installed
in
paragraph
30-63-00,
2,
for
the
timer
test
short or
open
circuit
at
the
brush-to-slip
ring
contact,
must
be
removed
so
that
the
connector
plug
can
be
disconnect
the
hamess
at
timer
and
check
resistance
replaced
in
timer
receptacle
(25-0001
thru
25-0999);’
from
each
De-leer
circuit
lead,
(Pins
D
8
F
of
hamess
reconnect
wire
to
Terminal
B
of
timer
for
25-1000
thru
plug,
12V)
CTerminal
C,
24V)
to
ground
with
a
low
25-TEA.
Two men
are
required
to
perform
this
test,
range
ohmmeter.
Ifthe
resultant
readings
are
not
1.55
one
in
the
pilot’s
compartment
to
monitor
the
ammeter
to
1.78
ohms,
disconnect
De-leer
lead
straps
to
while
the
other
checks
the
De-leer
boots.
The
man
in
measure
heater
resistance
individually.
Individual
boot
the
pilot’s
compartment
tums
the
De-leer
system
circuit
resistance
should
measure
between
4.58
and
526
breaker
switch
ON
while
the
man
outside
feels
the
ohms.
If
readings
in
the
first
check are
not
within
De-leer
boots
to
see
if
they
are
heating
properly.
The
accepted
limits
but
those
in
second
check
are,
the
man
in
the
pilot’s
compartment
observes
ammeter
for
trouble
is
probably
in
the
brush-to-slip
ring
area.
If
proper
readings
8
12
amperes_!12V)
[(8
amps
24~3]
readings
in
the
second
check
are
also
off,
the
De-leer
throughout
timing
sequence.
Tne
ammeter
needle
concemed
is
damaged
and
must
be
replaced.
should
deflect
every
90
seconds
in
response
to
the
30-6790
BRUSH
ASSEMBLY
RESISTANCE
switching
action
of
the
timer.
Each
time
this
occurs,
the
CHECK
man
in the
pilot’s
compartment
must
notify
the
man
inspecting
propeller
De-leer
boots
so
that
the
latter
can
To
check
for
an
open
circuit,
a short,
or
high
resistance
change
position
of his
hands
to
check
proper
heating
in
the
brush
assembly,
measure
resistance
from
face
sequence
of
propeller
De-leer
areas
(12
volt
AIC)
If
of the
brush
to
its
terminal
studs
with
a
low
range
any
irregularities
are
detected
a
continuity
check
ohmmeter.
If
this
resMance
measures
over
0.013
should
be
performed
on
the
win’ng
from
timer
to
brush
ohms,
locate
and
repair
cause
of
excessive
resistance.
block
holders
and
propeller
De-icer
terminal
If
resistance
is
infinite,
locate
and
correct
open
circuit
connections.
or
ground,
or
else
replace
brush
assembly.
Check
resistance
between
the
three
terminal
studs.
This
CAUTION
resistance
should
not
be
less
than
5
megohms.
Stand
clear
of
propeller,
verify
magnetos
OFF.
Use
extreme
caution
during
this
procedure.
30-68-00
BRUSH
REPLACEMENT
The
propeller
De-leer
brush
module
should
be
30-65-00
CONTlNUITY
TEST
replaced
when
a
minimum
of
114
inch
of
brush
After
removing
the
plug
from
the
timer,
use
an
;material
remains.
It
is
good
practice,
however,
to
ohmmeterto
check
continuity
from:
replace
modules
when
3/8
inch
of
brush
still
remains.
30-6600
OLDWILLWAYNE