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b.
Adjust
A3C7
and
A3C8
. for a
maximum
reading
on
the
MULTIMETER.
c. Adjust
A3C2
for
stability
as observed
on
the spectrum analyzer
as follows:
Turn
the
PWR
ADJ
control
Rl
to
the
max,
CCW
position.
Adjust
A3C2
for
stability
as observed
on
the spectrum analyzer.
Turn
the
PWR
ADJ
control to the
max.
CW
position.
Adjust
A3C2
if
necessary to
stabilize
the
unit.
5-4
EXCITER-TRANSMITTER
INTERFACE
When
connecting the Exciter to the Transmitter, tuning
of
the
transmitter
input
circuitry
will
be
facilitated
by
the use
of
a
3dB
20watt
pad
and
a
thru-line
wattmeter
between
the Exciter
and
the Transmitter.
If
these de-
vices
are
not
available
reduce the output
power
of
the
exciter
and
tune the
input
of
the
transmitter
until
a
somewhat
reasonable
match
is
obtained.
If
the Transmitter
is
already tuned to
exciter
frequency a "touch
up"
adjust-
ment
should
be
all
that
is
necessary.
If
the
IPA
of
the
transmitter
can
be
mistuned to the point
of
oscillation
be
sure
to
use the
3dB
pad.
It
is
poss-
ible
to
drive
large
amounts
of
power
back
into
the Exciter
from
an
oscillat-
ing
IPA
thereby destroying the output
transistor.
5-5
TROUBLESHOOTING
Refer
to
schematics for
waveform
and
voltage information.
Using
these,
the
theory
of
operation in Section 4
and
the
test
equipment
listed
should allow
a competent engineer to diagnose
most
problems.
If
factory
help
is
required,
it
is
as
close
as your telephone.
In
addition,
do
not attempt replacement
of
components
on
printed
circuit
boards
unless
you
are
familiar
with
this
work. All
PC
boards
can
be
severely
damaged
by
using the
wrong
tools or methods.
Do
not use a soldering iron over
25
watts
or anything
other
than 60/40
ROSIN
core
solder.
Use
a "solder sucker" or "sold-
er
wick" wire
to
remove
a component.
Because the
Power
Supplies are overload
protected,
it
is
possible for a
defect
on
the
A2
or
A3
boards to cause a voltage
to
be
either
missing or
less
than
nominal.
If
a voltage
is
low
or missing
remove
the load
and
see
if
the
volt-
age
returns.
5-6
POWER
TRANSFORMER
WIRING
1. Input Voltage
Change
a.
Change
jumpers
as
shown
on
next page.
-17-
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