2.3.2
Symptom:
No
Stereo Separation
First check the
"MONO"
switch
is
in normal
out
position. Connect a FM R F signal generator
output
modulated
by
a stereo
modulator
to
the rear FM antenna terminals, and check the stereo
beacon
is
turned
on
or
not.
If
not
turned
on, check
for
19 KHz
pilot
signal and 38 KHz switching
signal, usi,
ng
an
oscilloscope.
3.
AM
Alignment
Procedure
3.1
AM
I F
Alignment
1. Connect a sweep generator
to
the
test
point
®
or
J 1 07 and
an
alignment scope
to
the test
point
@.
2.
Rotate
each
core
of
I F transformer L
116
and L
117
for
maximum
height and
flat
top
symmetrical response.
3.2
AM
Frequency Range and
Tracking
Align
m
en
t
1. Set
AM
signal generator
to
525
KHz.
Turn
the
tuning
capacitor
fully
closed (place the
tuning
pointer
at the
low
end.) and adjust the
oscillator
coil L 115
for
maximum
audio
output.
2.
Set
the
signal generator
to
1650 KHz. Place the
tuning
pointer
in
the
high frequency end and
adjust the oscillator
trimmer
on
the
oscillator
tuning
capacitor (CA-2)
for
maximum
audio
output.
3. Repeat the step 1 and 2
until
no
further
adjustment
is
necessary.
4. Set the generator
to
600
KHz and
tune
the receiver
to
the
same
frequency and adjust a slug
core
of
AM
ferrite
rod antenna
for
maximum
output.
5.
Set the generator
to
1400
KHz and tune the receiver
to
the
same
frequency and adjust the
trimming
capacitors
of
Antenna (CA-1)
for
maximum
output.
6. Repeat the step 4 and 5
until
no
further
adjustment
is
necessary.
Note:
During
tracking alignment reduce the signal generator
output
as
necessary
to
avoid
AGC
action.
4.
FM
Alignment
Procedure
1.
Connect a FM signal generator
to
the FM antenna terminals and a oscilloscope and
an
audio
distortion
analyzer
to
the tape
output
jacks on the rear panel.
2.
Set the
FIVI
SG
to
87.5
MHz and provide
about
3
to
5
J.lV.
Place the
tuning
pointer
at
the
low
frequency end
by
rotating
the
tuning
knob
and adjust the core
of
oscillator coil L 103
to
obtain
maximum
audio
output.
3. Set the FM
SG
to
108.5
MHz
and provide
about
3
to
5
J.lV
output.
Rotate the tuning
knob
and
place the
tuning
pointer
at the h
ig
h frequency end and adjust the
trimming
capacitor C187
for
Maximum
output.
4. Repeat the step 2 and 3
until
no
further
adjustment
is
necessary.
5.
Set the FM
SG
to
90
MHz and tune the receiver
to
the
same
frequency. Decrease signal
generator
output
until
the audio
output
level decreases
with
the decreasing generator
output.
Adjust
the antenna coil
L101,
RF coil
L102
and IF
transformer
L105
for
minimum
audio
distortion.
6. Set the
FM
SG
to
106 MHz and tune the receiver
to
the
same
frequency.
Adjust
the
trimming
capacitor
CF-l,
CF-2
for
minimum
distortion.
7.
Repeat the step 5 and 6
until
no
further
adjustment
is
necessary.
8. Connect a DC
VTVM
with
±0.5
volt
range selected
to
the test
point
® (J'120) and adjust the
secondary core (upper)
of
discriminator
transformer L 107
so
that
no voltage reading
is
obtained on the
VTVM
at
no signal.
Next
set the FM
SG
to
98
MHz
and increase the
output
level
to
1
KJ.lV,
then tune the receiver
to
the
same
frequency
so
that
no
deflection
is
obtained on the
VTVM.
Adjust
primary
core
(bottom)
of
L 107
for
minimum
distortion,
and adjust the L 108
for
the
maximum
reading on
the
VTVM
connected
to
the J109.
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