Mooney M20K - Page 96

MOONEY
AIRCRAFT
CORPORATION
M20K
SERVICE AND
MAINTENANCE MANUAL
ANNUNCIATOR
TROUBLE
SHOOTING
(S/N
25-0001
thru 25-1
224)
conY.)
29.
The
"alt
air"
will
not
light
dun’ng
’’TEST"
but does
in normal
operation.
CR7
CAssy
A2)
open
30.
The
"alt air"
will
light
dun’ng
"TEST’
but
not
dun’ng
normal
operation.
CR6
(Assy A2)
open
31.The
"area nav"
is
the
only
channel that
lights
during
TEST’.
"area
nav" if
used,
effectivity
250001
thru
25-0717;
"start
power
on"
(effectivity
25-0718
thru
25-1224)
have
no
"TEST"
indication.
Q1
(Assy
Al)
defective
CR2
CAssy
Al)
open
32. Once
dimmed
the
"low fuels"
cannot
be
reset to
bright by momentan’ly depressing
the
"TEST"
switch.
CRI?
(Assy
Al)
open
33.
Neither
the
"high
low
vac"
or
the
"high
low
volts"
will flash when
low
vacuum
and/or low
voltage
occurs.
08
(Assy Al)
defective
U2
(Assy
Al defective
CR?
(Assy
Al)
not
suppling
+5 VDC
C5
(Assy
Al)
aefective~
34.
All
the
channels,
except
for
"area
nav",
light
up
when
the
landing
gear
is e~dended.
CR1
(Assy
A2)
shorted
24-39-06
-ANNUNCIATOR
TROUBLE
SHOOT1NG
(S/N
25-1225 thru
25-TEA)
The
following
is
a
brief
operational
analysis
which
pertains
to
the IA.I. annunciator
on
Mooney
M20K,
S/N 25-1225
thru
25-TEA.
1.0 GENERAL
the
internal
test
line,
TEST-,
and
the diode isolated
OUTTEST-. The dimmer
circuit,
applicable
to
certain
This
document is intended
to
be
a
guide
to
assist
a
channels,
requires
a
bias
source,
DIMBIAS,
with
a
service
technician in
understanding
the
theory
and
magnitude
of
12 VDC
to
dim
the
applicable
ACTIVE
operation
of International
Avionics,
Inc.
(IAl)
Part
channels,
approximately
3
VDC
to
maintain
the
dim
Numbers,
9500326000
8
9500326001 annunciators.
It
level
of
those
channels
previously
dimmed,
and
near
0
is
not
intended
to
serve
as a
bench service
aid in that
VDC
to
reset
the dimmed
channels to
a
bright
reference
designators
in
various
Figures
are
not
condition.
The
channels
having
the
capability
of
being
consistent
with those
found in
actual
annunciators.
dimmed
by
the above
circuitry
are
channels
x,
x,x,
x, x,
Service literature
is
available from
International
x,
and
x
Channel
i,
Landing
Gear,
dims
by
means
of
a
Avionics,
Incorporated (IAl),
1611 N.
1-35,
Suite
428,
separate
circuit and
is discussed
in Section 4.0
below.
Carrollton,
TX
75006,
telephone
number
(214)
446-1185,
to
identify
location
of
a
particular
component
and
exact
manner
in which
components
are
Interconnected.
The
following
paragraphs
address nine
(9)
basic
3
circuits
which,
used
singularly
or
in
multiple
ct
combinations,
compn’se
the annunciators. These
"";i
J
paragraphs
are
as
follows:
Paragraph
2 Power
Supply,
with
Test
8
Dim
switches
Paragraph
3 Flasher
Paragraph
4
Landing
Gear Indicators
Paragraph
5 Left
and
Right
Low Fuel
Paragraph
6
HiRo
Vac
Paragraph
7
Left Altemator/Low
Volts/Over
Volt
Paragraph
8
Right
Alternator/Over
Volt
Paragraph
9
Typical
Positive
Apply
W/Dim
Paragraph
10
Typical
Positive
Apply
W/O/Dim.
J]
2.0 POWER SUPPLY
The
Power
Supply,
shown in
Figure
i,
providesl2
ps
la
VDC,
reverse
voltage protection
by
means
of
CR1,
spike
and
overvoltage
filten’ng
by
means
of the
low
pass
network
of
R1, R2,
C1
and
C2
with
spike
clamping
provided
by
CR2.
The
actual
power
supply
is
a
12
VDC, integrated
circuit
regulator.
Output
filtering
is
provided
by
%2.
The Test
Switch,
S1,
switches
unflltered
aircraft
28
VDC
to
the internal
test
line,
identified with
the
mnemonic
TEST+.
This
signal,
diode
isolated
by
CR5,
is also
supplied
as
OUTTEST+.
Additionally
TEST+ is
applied
to
the
inverter
to
supply
24-39-06
18
OLDWILLWAYNE