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FM ALIGNMENT
CHART
SIGNAL
GENERATOR
DIAL
METER
WHERE
TO
CONNECTION TO | INPUT SIGNAL | SETTING
| CONNECTION
ADJUST
ADIUSTMENT,
RECEIVER
FREQUENCY
Connect FM sweep
10.7MHz
(400Hz, | Highest
Connect an
Tote
2o hs
| Rotate the core to
generator to the
100%, FM modu-
| frequency
oscilloscope
adjust so that the
TP3 through
lation)
(to extreme
between the
waveform becomes
a capacitor (5pF).
right.)
test point (TP4)
symmetrical
in right
Connect its ground
and ground (TP5)
and left as shown
side to the chassis
through a
in Fig. 7-1 (A) :
ground (TP2).
Capacitor
(Rotate the core of
(0.022 to 0.1
T4 fully counter-
MFD.)
|
clockwise.)
Same as step 1.
Same as step 1.
Same as
| Same as step 1.
T4
Adjust the core so
step 1.
that the waveform
("'s'' curve} becomes
Detection
symmetrical
in up
and down with the
best linearity as
Lt.
i
|
shown in Fig. 7-1
Repeat the steps 1 and 2 until no further improvement can be made.
Connect signal gene-
| 87.1MHz {400Hz, | Lowest
Connect
Local
Make the output be
rator through a
30%, FM modu-
frequency
V.T.V.M. to
oscillation
maximum,
dummy, including
lation)
(to extreme
the external
coll
Output impedance
left)
speaker jack.
L4
of signal generator
(Set the volume
4
to the FM antenna
control (VR3)
TPs
:
to ''max*'.)
|
(Refer to Figure
Frequency | 7-3) Ground lead of
coverage
generator connected
to the receiver
chassis (TP2).
Same as step 4.
JOOMHRz (400Hz, | Highest
Same as step 4.
|
Oscillation
Same as step 4.
5
30%, FM modu-
frequency
trimmer
.
lation)
(to extreme
TC1
right)
Same as step 4.
88MHz
(400Hz,
88MHz
Same as step 4.
RF coil
Same as step 4.
30%, FM modu-
a2
lation)
Track ing
ne
ee
i
eee
Pee
;
ame as step 4.
108MHz
(400Hz,
| 108MHz
Same as step 4,
RF
Same as step 4.
7
30%, FM modu-
trimmer TC2
ik.
lation)
|
|
I
|
8
Repat the steps 4 and 5 or 6 and 7 until no further improvement can be made.
FM IF CURVE
"S" CURVE
Figure 7—1
10.7MHz,
FM SWEEP
GENERATOR
FM FRONT
END
CIRCUIT
GND
GND
(TPS)
{TP2)
EXT. SPEAKER
FM
ANTENNA
GENERATOR
:
TERMINAL
DUMMY
(Fig. 7-3)
{TP2)
Figure 7—2
OSCILLOSCOPE
R |
Z« 75 (onm)
<<
-
Re
«
—V\V\A——_-—-
TO ANTENNA
Rt = 37.5
(ohm)
(ohm )
Re
er
at
= 50
(ohm)
=
h
poe
R2=*= 50
(ohm)
4
-__—.—_»
TO
CHASSIS
GROUND.
Z= OUTPUT
IMPEDANCE
OF SIGNAL
GENERATOR
Figure 7-3
E
Nge e
ee i ae a> SR n d e
ae ee e e e
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