Mooney M20R - Page 153

SERVICE
AND
MAINTENANCE
MANUAL
M20R
M
OON
EY
AIRC
RAFT
CORPORATION
TROUBLE
(con’t.)
PROBABLE
CAUSE
REMEDY
Timer
faulty.
Test
timer
per
Section
30-63-00.
Faulty
brush
block
assembly.
Check
for
broken
brushes
and test
for
opens.
Buss
load
meter/ammeter
shows
nor-
Open
circuit
or
high
resistance
See
"Open
in
De-leer"
above.
mal
current
part
of
cycle,
low
cur-
in
De-leer
or
slip
ring
assembly
rent
rest
of
cycle.
leads.
High
resistance
in
circuit
Check
contact
of
brushes
to
slip
rings
with
low
current.
per
Section
30-66-00;
correct
as
indi-
cated;
check
wiring
from
timer
to
De-
leers
for
loose
or
corroded
connections
or
partially
broken
wiring.
Correct
as re-
quired.
Ammeter
shows
low
current
over
en-
Aircraft
voltage
low
under
Check
voltage
into
switch.
tire
cycle.
normal
operating
conditions.
Switch,
or
circuit
breaker
faulty.
Check
voltage
up
to
and
out
of
switch
and
circuit
breaker.
If low
output
is
found
through
any
of
these
items,
re-
place
defective
component.
High
resistance
up
to
timer.
Check
for
partially
broken
wire,
or
loose
or
corroded
connection
in
wiring
be-
tween
aircraft
supply
and
timer
input.
Correct
as
required.
High
contact
resistance
in
timer.
Test
timer
per
manufacturer’s
service
data.
One
De-leer
element
(or
wiring
Perform
a
heat
test
on
each
De-leer
per
connections
to
De-leer)
in
each
Section
30-64-00.
Replace
defective
com-
cycle
out.
ponents.
Ammeter
shows
excess
current
over
Power
lead
shorted
to
ground.
Check
power
leads
from
Buss
load
me-
entire
cycle,
ter/ammeter
to
timer,
then
to
De-leers
for
evidence
of
damage
or
arcing.
(See
Sec-
tion
30-60-01).
If
ground
is
indicated,
lo-
cate
and
correct.
Timer
faulty.
Test
timer
per
Section
30-63-00.
Ammeter
indicates
normal
current
Short
to
ground
or
short
be-
Disconnect
leads
at
brush
block
timer,
part
of
cycle,
excess
current
remain-
tween
timer
and
brush
block.
check
for
short
or
ground.
Repair
as re-
der
of
cycle.
quired.
Short
between
slip
rings.
Clean
slip
ring
assembly
with MEK.
Timer
faulty.
Test
timer
per
Section
30-63-00.
Ammeter
does
not
"flicker"
each
90
Timer
ground
open;
timer
not
Disconnect
harness
at
timer
and
check
seconds.
cycling.
ground
connection
with ohmmeter
from
Terminal
G.
Timer
contacts
welded
together
Test
timer
per
Section
30-63-00.
If timer
(caused
by
short
in
electrical
is
faulty,
repair
or
replace
it,
but
insure
system).
that
short
causing
original
failure
has
been
located
and
corrected.
Ammeter
flickers
between
90
sec-
Loose
connection
between
air-
Trace
wiring
from
power
source
to
timer
ond
phase
periods,
craft
power
supply
and
timer
in-
input.
Insure
that
good
electrical
con-
put.
tacts
are
made
at
each
connection
in the
circuit.
Loose
or
poor
connection;
If
trouble
occurs
only
part
of
cycle,
deter-
timer
to
De-leers.
mine
which
De-leer is
affected,
check for
rough
or
dirty
slip
rings
causing
brush
to
REV.
7-96
30-61-01
Island Enterprises