Sony XR-C750RDS / XR-C850RDS / XR-C850RW Service Manual ▷ View online
– 25 –
PRECAUTION
1. Wipe the following components with an absorbent cotton cloth
moistened with alcohol before adjustment :
PB head
Pinch roller
Idler
Rubber belt
Capstan
2. Demagnetize the PB head using a head demagnetizer.
3. Be careful not to use a magnetized screwdriver.
4. After the adjustment is completed, lock the adjustment parts using
3. Be careful not to use a magnetized screwdriver.
4. After the adjustment is completed, lock the adjustment parts using
screws.
5. Unless otherwise specified, make adjustments at the specified
voltage (14.4 V).
Torque Measurement
Mode
Torque Meter
Meter Reading
35 – 65 g • cm
FWD
CQ-102C
(0.49 – 0.90 oz • inch)
FWD
0.5 – 5.0 g • cm
Back Tension
(0.01 – 0.07 oz • inch)
35 – 65 g • cm
REV
CQ-102RC
(0.49 – 0.90 oz • inch)
REV
0.5 – 5.0 g • cm
Back Tension
(0.01 – 0.07 oz • inch)
60 – 200 g • cm
FF, REW
CQ-201B
(0.83 – 2.78 oz • inch)
Tape Tension Measurement
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 60 g
REV
CQ-403R
(more than 2.12 oz)
SECTION 5
ELECTRICAL ADJUSTMENTS
SECTION 4
MECHANICAL ADJUSTMENTS
See the adjustment location from on page 29 for the adjust-
ment.
ment.
DECK SECTION
Tape Speed Adjustment
Procedure :
1. Put the set into the FWD PB mode.
1. Put the set into the FWD PB mode.
speed checker
or
frequency counter
10 k
Ω
set
REAR LINE OUT
test tape
WS-48A
(3 kHz, 0 dB)
WS-48A
(3 kHz, 0 dB)
Specification : Constant speed
Speed checker
Frequency counter
– 1.5 to + 2.5 %
2,955 to 3,075 Hz
Adjustment Location : See page 29.
DOLBY Level Adjustment
setting :
SHIFT button
: ON (light up SET UP
and PLAY MODE)
and PLAY MODE)
Preset 3 (PLAY MODE) button : NR off
SOUND (BAS) button
SOUND (BAS) button
: Center
SOUND (TRE) button
: Center
SOUND (BAL) button
: Center
SOUND (FAD) button
: Center
SOUND (VOL) button
: Maximum
Procedure :
1. Put the set into the FWD PB mode.
2. Adjust RV301 (L-CH) and RV401 (R-CH) so that level meter
1. Put the set into the FWD PB mode.
2. Adjust RV301 (L-CH) and RV401 (R-CH) so that level meter
reading is – 6 ± 1 dB (0.35 to 0.44 V).
Adjustment Location : See page 29.
test tape
P-4-D400
(400 Hz, 0 dB)
P-4-D400
(400 Hz, 0 dB)
main board
TP (DOLBY)
TP (DOLBY)
set
level meter
L-CH
R-CH
R-CH
0 dB = 0.775 V
– 26 –
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
TEST MODE
This set have the test mode function. In the test mode, FM Auto Scan/
Stop Level and MW Auto Scan/Stop Level adjustments can be
performed easier than it in ordinary procedure.
Stop Level and 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.
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 (XR-C850RDS : German model)
4. FM RDS S-Meter Adjustment
5. MW Auto Scan/Stop Level Adjustment
the following sequence.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise Focus Adjustment (XR-C850RDS : German model)
4. FM RDS S-Meter Adjustment
5. MW Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting :
SOURCE button : FM
Carrier frequency : 98.00 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
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
3. Push the preset 3 button.
Display
4. Adjust with the volume RV2 on TU10 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
Adjustment Location : See page 29.
SHUF1
REG
SHUF1
REG
SHUF1
REG
– 27 –
Procedure :
1. Set to the test mode. (See page 26.)
2. Push the SOURCE button and set to FM.
1. Set to the test mode. (See page 26.)
2. Push the SOURCE button and set to FM.
Display
Carrier frequency : 98.00 MHz
Output level
Output level
: 70 dB (3.2 mV)
Mode
: stereo
Modulation
: main : 1 kHz, 20 kHz deviation (26.5%)
sub
sub
: 1 kHz, 20 kHz deviation (26.5%)
19 kHz pilot : 7.5 kHz deviation (10%)
Procedure :
1. Tune the 98.00 MHz.
2. The then output level is supposing that 0 dB.
3. Adjust with the volume RV3 on TU10 so that the output level is
1. Tune the 98.00 MHz.
2. The then output level is supposing that 0 dB.
3. Adjust with the volume RV3 on TU10 so that the output level is
– 32 ± 2 dB then signal generator input set to – 20 dB.
Adjustment Location : See page 29.
FM Noise Focus Adjustment (XR-C850RDS : German model)
Setting :
SOURCE button : FM
FM Stereo Separation Adjustment
Setting :
SOURCE button : FM
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 26 dB
Adjustment Location : See page 29.
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 TU10 for
minimum reading.
minimum reading.
R-CH
R-CH
C
D
L-CH
R-CH
Adjust RV4 on TU10 for
minimum reading.
minimum reading.
Procedure :
FM RF signal
generator
antenna
terminal
terminal
set
0.01 µF
10 k
Ω
level meter
REAR LINE OUT
FM RF signal
generator
antenna
terminal
terminal
set
0.01 µF
10 k
Ω
level meter
REAR LINE OUT
Carrier frequency : 98.00 MHz
Output level
Output level
: 60 dB (1 mV)
Mode
: mono
Modulation
: 1 kHz, 75 kHz deviation (100%)
FM RDS S-Meter Adjustment
Setting :
SOURCE button : FM
Carrier frequency : 98.00 MHz
Output level
Output level
: 35 dB (56.2 µV)
Mode
: mono
Modulation
: no modulation
FM RF signal
generator
0.01 µF
antenna
terminal
terminal
set
3. Push the preset 3 button.
Display
4. Push the preset 10 button.
5. Adjust RV110 so that the display indication is “16.0”.
5. Adjust RV110 so that the display indication is “16.0”.
Display
SHUF1
REG
SHUF1
REG
SHUF1
REG
Specification : Display indication : 15.8 to 16.2.
Adjustment Location : See page 29.
– 28 –
MW Auto Scan/Stop Level Adjustment
Setting :
SOURCE
n MODE button : MW
AM RF signal
generator
AM dummy
antenna (50
antenna (50
Ω
)
antenna
terminal
terminal
set
15 pF
30
Ω
65 pF
Carrier frequency : 999 kHz
30% amplitude
modulation by
1 kHz signal
output level
30% amplitude
modulation by
1 kHz signal
output level
: 33 dB (44.7 µV)
Procedure :
1. Set to the test mode. (See page 26.)
2. Push the SOURCE button.
3. Push the MODE button and set to MW.
1. Set to the test mode. (See page 26.)
2. Push the SOURCE button.
3. Push the MODE button and set to MW.
Display
4. Push the preset 3 button.
Display
5. Adjust with the volume RV1 on TU10 so that the “MW”
indication turns to “MW0” indication on the display window.
But, in case of already indicated “MW0”, turn the RV1 so that
put out light “0” indication and adjustment.
But, in case of already indicated “MW0”, turn the RV1 so that
put out light “0” indication and adjustment.
Display
Adjustment Location : See page 29.
REG
TP
REG
TP
SHUF1
SHUF1
SHUF1
REG
TP
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