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8.
FM/AM
Tuner Alignment
er
P102
TC201
om
TC202
T201
IC
201
T202
Procedures
VR101 ©
P103
P104
T203
VR102
Alignment Location of TFM-924
FM/AM Tuner P.C. Board Ass'y
Fig. 12
Frequency
Counter
Loop
Antenna
AM SSG
3
Receiver
FM 75 2: 75 Q PAD
Fig. 13
8-(1)
FM Section
Sensitivity
Low Frequency
1.
2.
3;
4.
5.
6.
Connect
an RF generator to the antenna terminals on
the rear panel through a dummy antenna.
Set an RF generator to 90 MHz, a modulation of 1 kHz
and a deviation of 75 kHz to provide an input of 2 uV.
Connect
a VTVM
and an oscilloscope to the Rec. out
jacks on the rear panel.
Set the frequency display to 89.9 MHz.
Adjust
L104 so that '"'V. TUNE" -TP116 indicate 3.7
V by VTVM.
Adjust three coils L101, L102 and L103 in the tuning
gang to maximize the output.
High Frequency
7.
10.
11.
Set the
RF
generator
to 106 MHz, a modulation
of
1kHz
and a deviation
of 75 kHz to provide an input
of 2uV.
. Set the Frequency Display to 105.9 MHz.
. Adjust TC104 so that ''V. TUNE" TP116 indicate 18.0
V by VTVM.
Adjust the FM trimmers TC101, TC102 and TC103 in
the tuning gang to maximize the output.
Repeat
these
high
and
low
frequencies
adjustment
alternately until maximum sensitivity is obtained.
Distortion Meter
Oscilloscope
Descriminator, Distortion and Signal Gain
w
NOoS
co
. Press to FM position.
Connect
an
RF
generator,
1 kHz
modulation
and a
75 kHz deviation to the antenna terminals on the rear
panel through a dummy antenna.
Connect
an oscilloscope, Distortion Meter and
VT VM
to the Rec. out jacks on the rear panel.
Set the RF generator to 97.9 MHz.
Set the Frequency Display to a 97.9 MHz.
Connect
aDC VTVM
between TP111 and 112.
Adjust the core
indicated
arrow
A of T7101
for DC
VTVM
reading of 0 (zero) mV.
Adjust the core indicated arrow
B of T101 so that the
distortion is minimized at a value less than 0.4 %.
Multiplex and Stereo Separation
Multiplex
1.
Set the
stereo
signal
generator
as follows:
400 Hz
modulation
frequency,
7.5kHz
deviation
pilot,
67.5 kHz main and sub carriers. Connect its output to
the RF generator.
. Connect
an
RF
generator
to the antenna
terminals
through a dummy antenna.
. Connect
a VTVM,
an
oscilloscope
and
a distortion
meter to the Rec. out jacks on the rear panel.
Set the RF generator to 97.9 MHz and output of 1 mV.
Set the frequency display to 97.9 MHz.
. Connect the frequency counter to 19 kHz Test Point
(TP110).
Switch off the pilot signal of stereo modulator.
Adjust VR103
so that the frequency counter indicates
19 kHz (0 ~ -50 Hz).
Stereo Separation
9.
10.
11.
12.
13,
Switch the selector of stereo modulator to left channel
modulation.
Adjust VR102
so that the output of right channel is
minimized.
Switch
the selector of the modulator to right channel
modulation.
Adjust VR102 so that the left channel is minimized.
Set VR102
to a average,
if the separation of left and
right is different.
R-S77
No.2520
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