Sony MDX-C8970R Service Manual ▷ View online
17
3. Adjust the volume RV2 on TU101 by turning clockwise untill
“0” is shown next to “FM” on the display window, If “0” is
already shown or the volume RV2 has been turned too far,
turn it back counterclockwise untill “0” is disappeared once,
then try this adjustment.
already shown or the volume RV2 has been turned too far,
turn it back counterclockwise untill “0” is disappeared once,
then try this adjustment.
Display
Adjustment Location: See page 20.
SECTION 4
ELECTRICAL ADJUSTMENTS
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.
Scan/Stop Level and MW Auto Scan/Stop Level adjustments can
be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Turn ON the regulated power supply. (All LEDs on the set
1. Turn ON the regulated power supply. (All LEDs on the set
lights up, and the clock is displayed.)
Note:
Press the
[OFF]
button, if the clock is not displayed.
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
1. Push the
[OFF]
button.
MD SECTION
MD section adjustments are done automatically in this set.
See the adjustment location from on page 20 for the ad-
justment.
justment.
TUNER SECTION
0 dB=1 µV
Cautions during repair
When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.
cause 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 (Wide)
3. FM Stereo Separation Adjustment (Narrow)
4. FM RDS S-Meter Adjustment
5. MW Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment (Wide)
3. FM Stereo Separation Adjustment (Narrow)
4. FM RDS S-Meter Adjustment
5. MW Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting:
[SOURCE]
button : FM
Procedure:
1. Set to the test mode.
2. Push the
1. Set to the test mode.
2. Push the
[SOURCE]
button and set to FM.
Display
set
antenna jack
FM RF signal
generator
Carrier frequency
: 98.00 MHz
Output level
: 22 dB (12.6
µ
V)
Mode
: mono
Modulation
: 1 kHz, 22.5 kHz deviation (30%)
0.01
µ
F
SHUF
SHUF
18
FM Stereo Separation Adjustment (Wide)
Setting:
[SOURCE]
button : FM
Procedure:
1. Set to the test mode. (See page 17)
2. Push the
1. Set to the test mode. (See page 17)
2. Push the
[SHIFT]
button.
3. Push the
[4]
button four times.
4. Push the
[5]
button once and set to wide mode.
5. Adjust the volume RV3 on FM/AM tuner unit (TU101) for the
best separation.
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 24 dB
Adjustment Location: See page 20.
FM Stereo
Level meter
Level meter
signal generator
connection
reading (dB)
output channel
L-CH
L-CH
A
B
L-CH
R-CH
Adjust RV3 on TU101
for minimum reading.
R-CH
R-CH
C
R-CH
L-CH
D
FM RF signal
generator
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 : 1 kHz, 20 kHz deviation (26.5%)
sub : 1 kHz, 20 kHz deviation (26.5%)
:
19 kHz pilot: 7.5 kHz deviation (10%)
0.01
µ
F
set
antenna jack
+
–
–
level meter
10 k
Ω
LINE OUT jack (CNP601)
(75
Ω)
FM Stereo Separation Adjustment (Narrow)
Setting:
[SOURCE]
button : FM
Procedure:
1. Set to the test mode. (See page 17)
2. Push the
1. Set to the test mode. (See page 17)
2. Push the
[SHIFT]
button.
3. Push the
[4]
button four times.
4. Push the
[5]
button twice and set to narrow mode.
5. Adjust the volume RV4 on FM/AM tuner unit (TU101) for the
best separation.
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 18 dB
Adjustment Location: See page 20.
FM RF signal
generator
Carrier frequency : 98.00MHz
Output level
Output level
: 70 dB (3.2 mV)
Mode
: stereo
Modulation
: main : 1 kHz, 20 kHz deviation (26.5%)
sub : 1 kHz, 20 kHz deviation (26.5%)
sub : 1 kHz, 20 kHz deviation (26.5%)
:
19 kHz pilot: 7.5 kHz deviation (10%)
0.01
µ
F
set
antenna jack
+
–
–
level meter
10 k
Ω
LINE OUT jack (CNP601)
(75
Ω)
FM Stereo
Level meter
Level meter
signal generator
connection
reading (dB)
output channel
L-CH
L-CH
A
B
L-CH
R-CH
Adjust RV4 on TU101
for minimum reading.
R-CH
R-CH
C
R-CH
L-CH
D
19
MW Auto Scan/Stop Level Adjustment
Setting:
[SOURCE]
n
[MODE]
button : MW
Procedure:
1. Set to the test mode. (See page 17)
2. Push the
1. Set to the test mode. (See page 17)
2. Push the
[SOURCE]
button and set to FM.
3. Push the
[MODE]
button and set to MW.
Display
4. Adjust the volume RV1 on TU101 by turning clockwise untill
“0” is shown next to “MW” on the display window, If “0” is
already shown or the volume RV1 has been turned too far,
turn it back counterclockwise untill “0” is disappeared once,
then try this adjustment.
already shown or the volume RV1 has been turned too far,
turn it back counterclockwise untill “0” is disappeared once,
then try this adjustment.
Display
Adjustment Location: See page 20.
FM RDS S-Meter Adjustment
Setting:
[SOURCE]
button : FM
Procedure:
1. Set to the test mode. (See page 17)
2. Push the
1. Set to the test mode. (See page 17)
2. Push the
[SOURCE]
button and set to FM.
Display
3. Push the preset
[10]
button .
4. Adjust RV131 on MAIN board so that the display indication
is “13.0”.
Display
Specification: Display indication: 12.8 to 13.2.
Adjustment Location: See page 20.
set
antenna jack
FM RF signal
generator
Carrier frequency
: 98.00 MHz
Output level
: 35 dB (56.2
µ
V)
Mode
: mono
Modulation
: no modulation
0.01
µ
F
SHUF
SHUF
AM RF signal
generator
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
µ
V)
(50
Ω
)
set
AM dummy antenna
30
Ω
15 pF
65 pF
antenna jack
SHUF
TP
SHUF
TP
20
Adjustment Location:
– SET UPPER VIEW –
TU101
RV1
MW Auto Scan/Stop
Level Adjustment
MW Auto Scan/Stop
Level Adjustment
RV2
FM Auto Scan/Stop
Level Adjustment
FM Auto Scan/Stop
Level Adjustment
RV3
FM Stereo Separation
Adjustment (Wide)
FM Stereo Separation
Adjustment (Wide)
RV131
FM RDS S-Meter
Adjustment
FM RDS S-Meter
Adjustment
RV4
FM Stereo Separation
Adjustment (Narrow)
FM Stereo Separation
Adjustment (Narrow)
Front
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