Read Sony XR-C750 Service Manual online
– 23 –
TUNER SECTION
Cautions during repair
When the tuner unit is defective, replace it by a new one because
its internal block is difficult to repair.
its internal block is difficult to repair.
0 dB = 1 µV
Procedure :
1. Set to the test mode.
2. Push the SOURCE button and set to FM.
1. Set to the test mode.
2. Push the SOURCE button and set to FM.
Display
FM Auto Scan/Stop Level Adjustment
Setting :
Setting :
SOURCE button
: FM
FREQUENCY SELECT switch (E model) : FM 200k
SHUF1
Carrier frequency : 97.9 MHz
Output level
Output level
: 22 dB (12.6 µV)
Mode
: mono
Modulation
: 1 kHz, 22.5 kHz deviation (30%)
FM RF signal
generator
0.01 µF
antenna
terminal
terminal
set
Note on Adjustment
The adjustments of tuner section, should be performed according to
the following sequence.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise Focus Adjustment (E model)
4. AM (MW) Auto Scan/Stop Level Adjustment
The adjustments of tuner section, should be performed according to
the following sequence.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise Focus Adjustment (E model)
4. AM (MW) Auto Scan/Stop Level Adjustment
3. Push the preset 3 button.
Display
4. Adjust with the volume RV2 on TU11 so that the “FM” indication
turns to “FM0” indication on the display window.
But, in case of already indicated “FM0”, turn the RV2 so that put
out light “0” indication and adjustment.
But, in case of already indicated “FM0”, turn the RV2 so that put
out light “0” indication and adjustment.
Display
SHUF1
Adjustment Location : See page 25.
SHUF1
FM RF signal
generator
antenna
terminal
terminal
set
0.01 µF
10 k Ω
level meter
LINE OUT REAR
FM Stereo Separation Adjustment
Setting :
Setting :
SOURCE button
: FM
FREQUENCY SELECT switch (E model) : FM 200k
Carrier frequency : 97.9 MHz
Output level
Output level
: 70 dB (3.2 mV)
Mode
: stereo
Modulation
: main : 1 kHz, 33.75 kHz deviation (45%)
sub
sub
: 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot : 7.5 kHz deviation (10%)
L-CH stereo separation : A – B
R-CH stereo separation : C – D
The separations of both channels should be equal.
R-CH stereo separation : C – D
The separations of both channels should be equal.
Specification : Separation more than 28 dB
Adjustment Location : See page 25.
FM stereo
Level meter
Level meter
signal generator
connection
reading (dB)
output channel
L-CH
L-CH
A
B
R-CH
L-CH
Adjust RV4 on TU11 for
minimum reading.
minimum reading.
R-CH
R-CH
C
D
L-CH
R-CH
Adjust RV4 on TU11 for
minimum reading.
minimum reading.
Procedure :
TEST MODE
This set have the test mode function. In the test mode, FM Auto Scan/
Stop Level and AM (MW) Auto Scan/Stop Level adjustments can be
performed easier than it in ordinary procedure.
Stop Level and AM (MW) Auto Scan/Stop Level adjustments can be
performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Set the “OFF” mode.
2. Push the preset 4 button.
3. Push the preset 5 button.
4. Press the preset 1 button for more than two seconds.
5. Then the display indicates all lights, the test mode is set.
1. Set the “OFF” mode.
2. Push the preset 4 button.
3. Push the preset 5 button.
4. Press the preset 1 button for more than two seconds.
5. Then the display indicates all lights, the test mode is set.
<Release the Test Mode>
1. Push the OFF button.
1. Push the OFF button.
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