Read Sony XR-4750RDS / XR-C450RDS Service Manual online
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TUNER SECTION
0dB=1µV
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.
[Note]
Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise Focus Adjustment
4. FM Signal Meter Adjustment
5. AM (MW) Auto Scan/Stop Level Adjustment
Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise Focus Adjustment
4. FM Signal Meter Adjustment
5. AM (MW) Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting:
SOURCE button: FM
Procedure:
1. Set to the test mode. (See page 15).
2. Push the SOURCE button and set to FM.
1. Set to the test mode. (See page 15).
2. Push the SOURCE button and set to FM.
Display
FM
INTRO
REG
3. Push the preset 3 button.
Display
4. Adjust with the volume RV2 on TU1 so that the “FM” indica-
tion 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
INTRO
REG
FM
INTRO
REG
Adjustment Location: See page 18.
FM Stereo Separation Adjustment
Setting:
SOURCE button: FM
FM RF signal
generator
Carrier frequency : 98.0 MHz
Output level
Output level
: 70 dB (3.2 mV)
Mode
: stereo
Modulation
: main: 1 kHz, 20 kHz deviation (26.7%)
sub: 1 kHz, 20 kHz deviation (26.7%)
sub: 1 kHz, 20 kHz deviation (26.7%)
:
19 kHz pilot: 7.5 kHz deviation (10%)
0.01
µ
F
set
antenna jack (J1)
+
–
–
speaker out terminal
level meter
4
Ω
Procedure:
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 TU1
for minimum reading.
R-CH
R-CH
C
D
L-CH
R-CH
Adjust RV4 on TU1
for minimum reading.
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 30 dB
Adjustment Location: See page 18.
FM RF signal
generator
Carrier frequency
: 98.0 MHz
Output level
: 22 dB (12.6
µ
V)
Mode
: mono
Modulation
: 1 kHz, 22.5 kHz deviation (30%)
0.01
µ
F
set
antenna jack (J1)
FM Noise Focus Adjustment
Setting:
SOURCE button: FM
Procedure:
1. Tuner the 98.00 MHz.
2. The then output level is supposing that (A) dB.
3. Adjust with the volume RV3 on TU1 so that the output level is
1. Tuner the 98.00 MHz.
2. The then output level is supposing that (A) dB.
3. Adjust with the volume RV3 on TU1 so that the output level is
(A) –32 ± 2 dB then signal generator input set to –20 dB.
Adjustment Location: See page 18.
FM RF signal
generator
Carrier frequency : 98.00 MHz
Output level
Output level
: 60 dB (1 mV)
Mode
: stereo
Modulation
: 1 kHz, 75 kHz deviation (100%)
0.01
µ
F
set
antenna jack (J1)
+
–
–
speaker out terminal
level meter
4
Ω
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