Sony CDX-C6750 / CDX-C7500 Service Manual ▷ View online
– 17 –
AM RF signal
generator
dummy
antenna
antenna
terminal
terminal
set
SPEAKER OUT
level
meter
meter
+
–
30
Ω
4
Ω
15 pF
30 pF
FM RF signal
generator
dummy
antenna
50
Ω
50
Ω
4
Ω
antenna
terminal
terminal
set
SPEAKER OUT
+
–
level
meter
meter
0 dBs
–3 dBs
(fc–10)
fc
(fc+10)
(kHz)
+
–
FM CENTER
OUT
(Both side
of R24.)
IC1 pin
#¶
IC1 pin
#¢
digital
voltmeter
voltmeter
FM RF signal
generator
dummy
antenna
antenna
terminal
terminal
set
50
Ω
50
Ω
FM SENS/IF Adjustment
Setting:
SOURCE button
: FMI
D-BASS switch
: OFF
Frequency Select switch (E model) : FM 200K
Procedure:
Adjust for a maximum reading on level meter.
FEB1
87.5 MHz
Adjustment Location: See page 18.
AM SENS Adjustment
Setting:
SOURCE
n MODE button
: AM
D-BASS switch
: OFF
Frequency Select switch (E model) : AM 10K
SECTION 3
ELECTRICAL ADJUSTMENTS
TUNER SECTION
0 dB = 1
µ
V
Cautions during repair
When the tuner assy is defective, replace it by a new one
because its internal block is difficult to repair.
because its internal block is difficult to repair.
FM Center Adjustment
Setting:
SOURCE button
: FMI
D-BASS switch
: OFF
Frequency Select switch (E model) : FM 200K
Carrier frequency: 97.9 MHz
Output lever
Output lever
: 60 dB (1 mV)
Mode
: mono
Modulation
: 1 kHz, 75 kHz deviation (100%)
Procedure:
Adjust for a maximum reading on level meter.
IFT1, 3
1,400 kHz
Adjustment Location: See page 18.
Procedure:
1. Adjust IFT4 on TU601 so that the reading on the digital
1. Adjust IFT4 on TU601 so that the reading on the digital
voltmeter becomes in 0
±
30 mV.
2. Output an Fcenter 10 dB signal output from FM RF signal
generator so that the speaker out is –20 dBs.
3. Change the FM RF signal generator frequency and check the
deviation of the frequency on + side and – side when the speaker
out drops 3 dB. (Both + side and – side is approx. 50 kHz.)
out drops 3 dB. (Both + side and – side is approx. 50 kHz.)
4. Re-adjust IFT4 on TU601 when the difference deviation of the
frequency does more than 10 kHz.
Adjustment Location: See page 18.
– 18 –
– tuner assy (TU601) (component side) –
AM AUTO
SCAN/STOP
LEVEL ADJ
IFT3
AM SENS
ADJ
IFT3 IFT1
FEB1
FM SENS/IF
ADJ
IFT4
FM CENTER
ADJ
– tuner assy (TU601) (conductor side) –
IC1
R24
S-METER
OUT
FM CENTER
OUT
OUT
‘
’
+
–
digital
voltmeter
voltmeter
S-METER OUT
AM RF signal
generator
dummy
antenna
antenna
terminal
terminal
set
SPEAKER OUT
level
meter
meter
+
–
30
Ω
4
Ω
15 pF
30 pF
Carrier frequency: 1000 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)
Procedure:
1. Adjust IFT3 on TU601 so that the reading on the digital
1. Adjust IFT3 on TU601 so that the reading on the digital
voltmeter is 1.5
±
0.2 V.
Adjustment Location: tuner assy (TU601)
AM Auto Scan/Stop Level Adjustment
Setting:
SOURCE
n MODE button
: AM
D-BASS switch
: OFF
Frequency Select switch (E model) : AM 10K
Adjustment Location: tuner assy (TU601)
– 19 –
IC3
CN1
IC1
CN2
FOCUS GAIN ADJ
RV4
TP
(RF. GND)
IC2
TP
(RF)
CN3
RV1
FOCUS BIAS ADJ
RF signal waveform
VOLT/DIV: 200 mV
TIME/DIV: 500 nS
TIME/DIV: 500 nS
level: 1.0 – 1.5 Vp-p
SERVO board
TP (RF)
TP (RF. GND)
oscilloscope
+
–
–
CD SECTION
Note:
1. CD Block basically constructed to operate without adjustment.
1. CD Block basically constructed to operate without adjustment.
Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use the oscilloscope with more than 10 M
3. Use the oscilloscope with more than 10 M
Ω
impedance.
4. Clean an objective lens by an applicator with neutral detergent
when the signal level is low than specified value with the following
checks.
checks.
Focus Bias Adjustment
Setting: This adjustment is performed with the set placed
horizontally.
Focus Gain Adjustment (Coarse adjustment)
This adjustment is not required unless the following parts are replaced:
•
•
Optical pick-up
•
RV4
Procedure:
1. Set RV4 to the standard position. (mechanical center)
2. Check whether operation noise (while noise type) caused by
1. Set RV4 to the standard position. (mechanical center)
2. Check whether operation noise (while noise type) caused by
the 2-axis device (lens section of the optical pick-up) is
abnormally loud.
If the operation noise is too loud, turn RV4 slightly counter-
clockwise.
abnormally loud.
If the operation noise is too loud, turn RV4 slightly counter-
clockwise.
•
If the gain is too low:
Focus does not function and no music is selected.
Focus does not function and no music is selected.
•
If the gain is too high:
Noise caused by scratches and dust is heard and the operation
becomes unstable.
Noise caused by scratches and dust is heard and the operation
becomes unstable.
Adjustment Location: servo board
Adjustment Location: servo board (component side)
Procedure:
1. Connect an oscilloscope between TP (RF) and TP (RF. GND)
1. Connect an oscilloscope between TP (RF) and TP (RF. GND)
on the SERVO board.
2. Connect the power supply.
3. Push the RESET button (S900) on the MAIN board.
4. Insert the disc (YEDS-18) and playback.
5. Adjust RV1 so that the oscilloscope waveform is clear and check
3. Push the RESET button (S900) on the MAIN board.
4. Insert the disc (YEDS-18) and playback.
5. Adjust RV1 so that the oscilloscope waveform is clear and check
RF signal level is correct or not.
Note: Clear RF signal waveform means that the sharp “
≈
” can be
clearly distinguished at the center of the waveform.
• When observing the eye pattern, set the oscilloscope to AC range
and raise the vertical sensitivity so that it may be easily seen.
Adjustment Location: servo board
– 20 –
4-1. IC PIN DESCRIPTION
• IC801 MB90574PFV-G-192-BND (SYSTEM CONTROL)
Pin No.
Pin Name
I/O
Pin Description
1
LD ON
O
Laser ON/OFF control output
2
FOK
I
Focus OK signal detection input
3
XLAT25
O
CD signal processing latch output
4
DATA25
O
CD signal serial data output
5
XRST
O
Reset output to CD signal processor IC.
6
GFS
I
GFS signal detection input
7
NIL
—
Not used. (Connect to ground in this set.)
8
VCC
—
Power supply pin (+5 V)
9 – 11
NIL
—
Not used. (Open)
12
FLS SI/NOSE1
I
Front panel attachment detection input
13
LCD SO/FLS SO
O
LCD serial data output
14
LCD CKO
O
LCD serial clock output
15
BEEP
O
BEEP output
16
NIL
—
Not used. (Open)
17
SQ SI
I
Sub Q data input
18
NIL
—
Not used. (Connect to ground in this set.)
19
SQ CKO
O
Sub Q read clock output
20
UNI SI
I
BUS system serial interface input
21
UNI SO
O
BUS system serial interface output
22
UNI CK
I/O
BUS system serial clock input/output
23
C IN
I
Track jump No. count input
24
SIRCS
I
Remote commander input
25
TXT SI
I
CD-TEXT data input
26
NIL
—
Not used. (Connect to ground in this set.)
27
TXT CKO
O
CD-TEXT data read clock output
28
CLOK25
O
CD signal processing serial clock output
29
SYSRST
O
System reset output
30
DEEMPH
O
De-emphasis output
31
AMP ATT
O
Power amplifier attenuator control output
32
MD ON
O
CD mechanism power control output
33
VSS
—
Ground
34
C
—
Power stabilization capacitor pin
35
CD ON
O
CD power control output
36
BUS ON
O
BUS ON control output
37
AD ON
O
Power control output of A/D conversion.
38
DVCC
—
VREF input of D/A converter.
39
DVSS
—
Ground of D/A converter.
40
NIL
—
Not used. (Open)
41
ANGLE
O
LCD view angle alignment output (Not used in this set.)
42
AVCC
—
Analog power supply pin (+5 V)
43
AVRH
—
VREF + input of A/D converter.
44
AVRL
—
VREF – input of A/D converter.
45
AVSS
—
Analog ground
46 – 48
KEY IN0 – 2
I
Key input 0 – 2
49
RC IN0
I
Rotary commander input 0
50
QUALITY
I
Not used in this set.
51
NIL
—
Not used. (Connect to ground in this set.)
52
MPDH
I
Tuner multi path input (Not used in this set.)
53
S-METER
I
S-meter voltage detection input
54
VCC
—
Power supply pin (+5 V)
55
NS MASK
O
Not used in this set.
SECTION 4
DIAGRAMS
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