Mooney M20M - Page 143

MOONEY AIRCRAFT CORPORATION
M20M
SERVICE
AND MAINTENANCE
MANUAL
TROUBLE
(con"t.)
PROBABLE
CAUSE
REMEDY
Buss load
meter/ammeter
Timer
faulty.
Test timer
per
Section
30-63-00.
shows normal
current
part
of
cycle,
zero
current
rest
of
cycle.
(con"t.)
Faulty
brush
block
assembly.
Check
for
broken
brushes
and
test
for
opens.
Bus load
meter/ammeter
shows
Open
circuit
or
high
resistance
in
See
"Open
in
De-leer" above.
normal
current
part
of
cycle,
low
De-leer
or
slip
ring
assembly
current
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
indicated;
check
wiring
from
timer
to
De-leers
for
loose
or
corroded
connections
or
partially
broken
wiring.
Correct
as
required.
Bus
Load/Ammeter
shows
low
Aircraft
voltage
low
under
Check
voltage
into
switch.
current
over
entire
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,
replace
defective
component.
High
resistance
up
to
timer.
Check
for
partially
broken
wire,
or
loose
or
corroded connection
in
wiring
between 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
connections
to
De-leer)
in each
per
Section
30-64-00.
Replace
cycle
out,
defective
components.
Bus
Load/Ammeter
shows
Power lead
shorted
to
ground.
Check
power
leads from Buss load
excess
current
over
entire
meterlammeter
to
timer,
then
to
cycle.
De-leers for evidence
of
damage
or
arcing.
(See
Section
30-60-01).
If
ground
is
indicated,
locate
and
correct.
Timer
faulty.
Test
timer
per
Section
30-63-00.
Bus
Load/Ammeter
indicates
Short
to
ground
or
short
between
Disconnect
leads
at
brush block
normal
current
part
of
cycle,
timer and
brush
block,
timer,
check
for
short
or
ground. Repair
excess
current
remainder
of
as
required.
cycle.
Short between
slip rings.
Clean
slip
ring
assembly
with
MEK.
Timer
faulty.
Test
timer
per
Section 30-63-00.
Bus
Load/Ammeter
does not
Timer
ground
open;
timer
not
Disconnect
harness
at
timer
and
check
’Ylicker"
each
90
seconds,
cycling.
ground
connection
with
ohmmeter
from
terminal
G.
Timer
contacts
welded
together
Test
timer
per
Section
30-63-00.
If
(caused
by
short
in
electrical
timer
is
faulty,
repair
or
replace
it,
but
system),
insure
that
short
causing
original
failure
has been
located and
corrected.
Bus
Load/Ammeter
flickers Loose connection between
Trace
wiring
from
power
source
to
between
90
second
phase
aircraft
power
supply
and timer
timer
input.
Insure
that
good
electrical
periods,
input,
contacts
are
made
at
each
connection
in
the
circuit.
30-61-02
4-99
18
OLDWILLWAYNE