Raytheon Beech Baron E55 - Page 406

Raytheon
Aircraft
BEECH
BARON
55
AND
58
SHOP
MANUAL
SYNCHRONIZER
FUNCTIONAL
TEST
Proper operation
of
the
propeller
synchronizer
can
be
determined
by
the
following
method.
Manually
adjust
the
pro-
peller
control levers
to
equal
rpm.
Turn
the
propeller
synchronizer
ON.
Slowly
adjust,
in
small
increments,
either
pro-
peller
governor
to
increase
or
decrease
rpm.
The
rpm
should
remain
synchronized
over
a
limited
range
predetermined
by
the
synchronizer.
Turn
the
synchronizer
OFF and
establish
a
maximum
of
25
rpm
difference
be-
tween
the
engine
rpm
of
the left and
right
engines.
Turn
the
synchronizer
ON
and
the
rpm
of
both
engines
should
synchronize.
SYNCHRONIZER
CHECKS
These checks
will
help
locate
the
source
of
trouble
should
the
synchronizer
system
malfunction.
If
no
malfunctions
are
found
among
the
units
being
tested,
the transistorized
control box
is
probably
the
source
of
trouble.
An
ohmme-
ter,
voltmeter
and
oscilloscope
are
required
to conduct the
tests
below.
SYNCHRONIZER WIRING CHECK
a.
To
eliminate
the
most
obvious
causes
for
malfunction
make
sure
that
the
airplane
battery
master
switch
is
ON,
that
the
propeller synchronizer
circuit
breaker
is
not
tripped,
and
that
the
modified
Jones
plug
receptacle
is
properly
mated
with
the
plug
in
the
airplane
electrical
system.
b.
Unplug
the
control
box,
turn
the
airplane
master
switch
OFF,
and
pull
the
propeller
synchronizer
circuit
breaker
before
proceeding
further
with these
checks.
c.
Complete
the
following
resistance
checks:
(See
Figure
7-2A.)
I
cnrrr~ou
I
CAUTION
Zero
the
ohmmeter and read
on
the X1
orXIO
scale
during
the
following
checks.
Do
not
use a
probe
greater
than
0.045
inch
in
thickness.
Insert
and
remove
the
probe
carefully
to
avoid
damaging
the
pin
connectors.
NOTE
Readings
may
be
20
percent
higher
during
heat
soak
following
engine
shutdown.
1.
Check
the
resistance between
pin
1
and
airplane
ground.
The
ohmmeter
should
indicate
0
ohms.
2.
Check
the
resistance between
pin
2
and
airplane
ground.
The
ohmmeter
should
indicate
an
open
circuit.
3.
Check
the
resistance
between
pin
3
and
airplane
ground.
The
ohmmeter
should indicate
52
68
ohms.
4.
Check
the
resistance between
pin
4
and
airplane
ground.
The
ohmmeter
should
indicate
an
open
circuit.
5.
Check
the
resistance
between
pin
5
and
airplane
ground.
The
ohmmeter
should
indicate
52
68
ohms.
6.
Check the
resistance between
pin
6
and
airplane
ground.
The
ohmmeter
should
indicate
an
open
circuit.
7.
Check
the
resistance
between
pin
7
and
airplane
ground.
The
ohmmeter
should
indicate
an
open
circuit.
8.
Check
the
resistance between
pins
4
and
7.
The
ohmmeter
should indicate
112
138
ohms.
7-6
E16