Mooney M20K - Page 100

SERVICE
AND
MAINTENANCE
MANUAL
M20K
MOONN
AIRCRAFT
CORPORATION
DS9
3323
tASH
CR19
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1NS8b5
R57
CR\7
CR22
tOW
UAC
6.OK
INSebS
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CR4
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l-ItGH
V~C
OVGRRIDE
TeST+
CRBI
IN46b5
The
signal
FLASH
will,’
however,
remove
this
drive
signal
as
the
flasher
cycles,
thus
flashing
DS9.
A
+28
VDC
signal
applied
to
HIGH
VAC
OVERRIDE
will
bypass
the
above
network
and
drive
Q11
into
conduction
regardless
of
the
state
of
LOW
VAC
28vDC~
DStO
regardless
ofihe
state
of
LOW
VAC
INPUT.
The
j~e
565
!R61
INPUT.
Similarly
TEST+
will drive
Q~1
into
conduction
ckannel
HighRow
Vac
does
not
dim.
R62
VOLT
7.0
LEFTALTERNATOR
now
VOLTSI
CR29
OVER
VOLT
R60
CR2a
U6
IN4005
The
Left
AltematorRow
Volts/Over
Volts
circuits are
/4-UCJ302
CR23
shown
in
Figure
6.
This
channel
is
designed
to
accept
three
signals,
the
analog
signal
LAINPUT
from a
iPs~4
current
sensor,
the
+28
VDC
signal
LOVERRIDE
from
the
overvoltage
tripped
output
on
the
left
altemator
regulator,
and
one
signal
derived
intemally
that
R63
indicates
that
the
aircraft
bus
voltage
is
less
than
26.5
CR27
VDC.
When
low
voltage
is
detected
internally
or
when
IN~005
low
current
is
detected
the
annunciator
channel
flashes,
and
when
overvoltage
tripped
detected
the
annunciator
channel
illuminates
steady.
Comparator
U6
monitors
the
aircraft
28
VDC
by
compan’ng
the
voltage
at
the
arm
of
R68
with
the
regulated
voltage
at
the
junction
of
R64
and
R65.
The
output
of
U6,
an
SVDC
open
collector
comparator
is
normally
low.
When
low
t.ssoootxxx
~.6soqqtxxx
~R78
voltage
is
detected
the
output
of
U6
rises
and
drives
573
012
into
conduction
through
the
bias
network
R60,
u7
CR24,
and
CR28,
thus
illuminating
DS10.
In
a
/4-UC3X)2
similar
to
the
Hi/Lo
Vac
channel,
the
signal
FLASH
will
remove
this
drive
signal
as
the
flasher
cycles,
thus
R72
flashing
DS10.
A
+28
VDC
signal
applied
to
~.saoootxxx
LOVERRIDE
will
bypass
the
above
network
and
drive
_ LOWVOLTS/OVER
VOLT
012
into
conduction
regardless
of
the state
of
the
comparator
U6.
Similarly
TEST+
will
drive
012
into
conduction
regardless
of
the
state
of
the
comparator
24-39-06
21
OLDWILLWAYNE