Sony MDX-C8970 User manual

MICROFILM
SERVICE MANUAL
Model Name Using Similar Mechanism MDX-C7970
Base Mechanism Type MG-164NF-138
Optical Pick-Up Name KMS-241B/J1NP
US Model
SPECIFICATIONS
MDX-C8970
FM/AM MINIDISC PLAYER

2
Notes on chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Flexible Circuit Board Repairing
• Keep the temperature of the soldering iron around 270 ˚C dur-
ing repairing.
• Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
• Be careful not to apply force on the conductor when soldering
or unsoldering.
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.
The laser diode in the optical pick-up block may suffer electro-
static break-down because of the potential difference generated
by the charged electrostatic load, etc. on clothing and the human
body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
Never look into the laser diode emission from right avove when
checking it for adustment. It is feared that you will lose your sight.
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK
(KMS-241B/J1NP)
The laser diode in the optical pick-up block may suffer electro-
static break-down easily. When handling it, perform soldering
bridge to the laser-tap on the flexible board.Also perform m easures
against electrostatic break-down sufficiently before the operation.
The flexible board is easily damaged and should be handled with
care.
laser-tap
OPTICAL PICK-UP FLEXIBLE BOARD
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK !OR DOTTED
LINE WITH MARK !ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.

3
1. GENERAL
Location of controls ........................................................ 4
Resetting the unit ............................................................ 4
Detaching the front panel................................................ 4
Preparing the rotary commander .................................... 4
Setting the clock.............................................................. 4
Installation....................................................................... 5
Connections..................................................................... 7
2. DISASSEMBLY ......................................................... 9
3. ELECTRICAL ADJUSTMENTS
Test Mode ........................................................................ 15
MD Section ..................................................................... 15
Tuner Section .................................................................. 15
4. DIAGRAMS
4-1. Block Diagram – SERVO Section – ............................... 19
4-2. Block Diagram – TUNER Section – .............................. 20
4-3. Block Diagram – MAIN Section – ................................. 21
4-4. Block Diagram
– DISPLAY/KEY CONTROL Section –........................ 22
4-5. Block Diagram
– BUS CONTROL/POWER SUPPLY Section – ........... 23
4-6. Note for Printed Wiring Boards and
Schematic Diagrams ....................................................... 24
4-7. Printed Wiring Board – SERVO/SENSOR Boards – ..... 25
4-8. Schematic Diagram
– SERVO (1/2)/SENSOR Boards – ............................... 26
4-9. Schematic Diagram – SERVO Board (2/2) – ................. 27
4-10. Printed Wiring Board
– MAIN Board (Component Side) – .............................. 28
4-11. Printed Wiring Board
– MAIN Board (Conductor Side) – ................................ 29
4-12. Schematic Diagram – MAIN Board (1/5) – ................... 30
4-13. Schematic Diagram – MAIN Board (2/5) – ................... 31
4-14. Schematic Diagram – MAIN Board (3/5) – ................... 32
4-15. Schematic Diagram – MAIN Board (4/5) – ................... 33
4-16. Schematic Diagram – MAIN Board (5/5) – ................... 34
4-17. Printed Wiring Board – POWER Board – ...................... 36
4-18. Schematic Diagram – POWER Board –......................... 37
4-19. Printed Wiring Board – DISPLAY Board – ................... 38
4-20. Schematic Diagram – DISPLAY Board – ...................... 39
4-21. Printed Wiring Board – RELAY Board – ....................... 40
4-22. Schematic Diagram – RELAY Board – .......................... 41
4-23. IC Pin Function Description ........................................... 49
5. EXPLODED VIEWS................................................ 63
6. ELECTRICAL PARTS LIST ............................... 67
TABLE OF CONTENTS

4
SECTION 1
GENERAL This section is extracted from
instruction manual.

5

6

7

8

9
SECTION 2
DISASSEMBLY
Note: Follow the disassembly procedure in the numerical order given.
MECHANISM DECK (MG-164NF-138)
2 two claws
4 sub panel ass’y
1 three screws
(PTT2.6
× 6)
3 connector
(CN701)
1 screw
(PTT2.6
× 6)
2 claw
1 two screws
(PTT2.6
× 4)
2 mechanism deck
(MG-164NF-138)
3 flexible board
(CN202)
SUB PANEL ASS’Y

10
SERVO BOARD
MAIN BOARD
3 two screws
(BVTT2
× 4)
1 flexible board
(CN101)
3 two screws
(BVTT2
× 4 )
4 servo board
1 flexible board
(CN103)
2 sensor flexible board
(CN102)
7 two screws
(PTT2.6
× 10)
8 cord (with connector)
(ANT)
0 seven screws
(PTT2.6
× 10)
2 two screws
(PTT2.6
× 10)
!¡ Remove the heat sink
in the direction of the arrow.
5 insulating sheet
4 main board
3 three ground point screws
1 two connectors
(CN101, 291)
9 cord (with connector)
(RCA)
6 Remove the solder of the cord
(with connector) (ANT).

11
MD COVER ASS’Y
FLOAT BLOCK
1 four screw
s
(B2 × 3)
3 MD cover ass’y
2 Pushing the cassette holder in the arrow A direction with a screwdriver,
disengage the shaft (MD cover guide) from the groove of MD cover ass’y.
Note : Be careful not to damage the optical pick-up
when pushing the cassette holder with a screwdriver.
shaft (MD cover guide)
cassette holder
A
1 spring (float B)
1 spring (float B)
2 two springs (float F)
3 Pushing the arrow A part,
raise the float block upward at the front to unlock.
A
float block
lever (lock R)
lever (lock L)

12
LO MOTOR ASS’Y (LOADING) (M903)
LEVER ASS’Y (LE)
4 Remove the bracket (LO)
in the direction of the arrow
A .
1 Remove solder of the motor (M903).
5 LO motor ass’y (loading) (M903
)
2 spring (rack)
3 claw
A
2 stopper washer
3 lever ass’y (LE)
4 roller (gear E)
1

13
HOLDER ASS’Y
CHUCKING ARM ASS’Y
2 stop ring E (1.5)
2 stop ring E (1.5)
3 lever (lock L)
2 stop ring E (1.5)
2 stop ring E (1.5)
4 Remove the holder ass’y
in the direction of the arrow.
1 spring (CHKG)
1 spring (CHKG)
3 lever (lock R)
1 Remove the chucking arm ass’y
in the direction of the arrow.
holder ass’y

14
OPTICAL PICK-UP (KMS-241B/J1NP)
SL MOTOR ASS’Y (SLED) (M902)/SP MOTOR ASS’Y (SPINDLE) (M901)
6 bearing (SL)
5 feed screw ass’
y
3 screw
(K2
× 3)
2 shaft (OPTL)
1 two screws
(K2
× 3)
7 optical pick-up
(KMS-241B/J1NP)
4 screw
(B2
× 3)
4 screw
(P1.7
× 1.8)
5 bracket (SL)
9 two screws
(P1.7
× 1.8)
0 bracket (SP)
!¡ SP motor ass’y
(spindle) (M901)
7 screw
(B2
× 3)
2 two screws
(PSW2
× 8)
3 sensor board
1 Remove solders
of motors (M901, 902).
8 base (SL)
6 SL motor ass’y
(sled) (M902)

15
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.
Display
Adjustment Location: See page 17.
SECTION 3
ELECTRICAL ADJUSTMENTS
TEST MODE
This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and AM 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
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 [OFF] button.
MD SECTION
MD section adjustments are done automatically in this set.
See the adjustment location from on page 17 for the ad-
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.
Note: Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop LevelAdjustment
2. FM Stereo Separation Adjustment (Wide)
3. FM Stereo Separation Adjustment (Narrow)
4. AM 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 [SOURCE] button and set to FM.
Display
set
antenna jack (CN101)
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

16
FM Stereo Separation Adjustment (Wide)
Setting:
[SOURCE] button : FM
Procedure:
1. 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.
Specification: Separation more than 24 dB
Adjustment Location: See page 17.
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 : 70 dB (3.2 mV)
Mode : stereo
Modulation : main: 1 kHz, 33.75 kHz deviation (45%)
sub : 1 kHz, 33.75 kHz deviation (45%)
:19 kHz pilot: 7.5 kHz deviation (10%)
0.01 µ F
set
antenna jack (CN101)
+
–
level meter
10 k
Ω
LINE OUT jack (CNP601)
(75
Ω)
FM Stereo Separation Adjustment (Narrow)
Setting:
[SOURCE] button : FM
Procedure:
1. Push the [SHIFT] button.
2. Push the [4] button four times.
3. Push the [5] button twice and set to narrow mode.
4. 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.
Specification: Separation more than 18 dB
Adjustment Location: See page 17.
FM RF signal
generator
Carrier frequency : 98.00 MHz
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%)
:19 kHz pilot: 7.5 kHz deviation (10%)
0.01 µ F
set
antenna jack (CN101)
+
–
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

17
AM Auto Scan/Stop Level Adjustment
Setting:
[SOURCE] n[MODE] button : AM
Procedure:
1. Set to the test mode. (See page 15.)
2. Push the [SOURCE] button and set to FM.
3. Push the [MODE] button and set to AM.
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.
Display
Adjustment Location: See page 17.
AM RF signal
generator
Carrier frequency : 999 kHz
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 (CN101)
SHUF
TP
SHUF
TP
TU101
RV1
AM Auto Scan/Stop
Level Adjustment
RV2
FM Auto Scan/Stop
Level Adjustment
RV3
FM Stereo Separation
Adjustment (Wide)
RV4
FM Stereo Separation
Adjustment (Narrow)
Front
Adjustment Location:

18

MDX-C8970
1919
SECTION 4
DIAGRAMS
4-1. BLOCK DIAGRAM – SERVO Section –
F
C B
D A
E
I J
J
I
B
A
C
D
E
F
DETECTOR
1
2J
I
4
5
6
7
A
B
C
D
8
9
E
F
LDPD
LASER DIODE
ILCC
PD
OPTICAL PICK-UP
(KMS-241B/J2N)
AUTOMATIC
POWER
CONTROL
Q302
11
10
APC
PD
LD/PD
AMP
12
APCREF
I-V
AMP
I-V
AMP
AT
AMP B.P.F. 29 30
WBL
ADFM ADIN
32
ADFG
ABCD
AMP
FOCUS
ERROR AMP
TRACKING
ERROR AMP
35
34
26
28
ABCD
FE
TE
SE
V-I
CONVERTER
20
F0CNT WBL
3T EQ
+3.3V
SERIAL/
PARALLEL
CONVERTER,
DECODER
COMMAND
1716 18
SWDT
SCLK
XLAT
RF AMP
B.P.F.
46
RFO 40 RF AGC
& EQ
AGCI
EQ
38
RF
RF AMP,
FOCUS/TRACKING ERROR AMP
IC302
TEMP
48 47
MORFO
MORFI
3T
PEAK &
BOTTOM
WBL
33
AUX
73 62
37
PEAK
36
BOTM
FOCUS/TRACKING COIL DRIVE,
SPINDLE/SLED MOTOR DRIVE
IC303
6
8
OUT4F
OUT4R
M
M901
(SPINDLE)
27
25
OUT2F
OUT2R
M
M902
(SLED)
21
23
OUT1F
OUT1R
12
10
OUT3F
OUT3R
FCS+
FCS–
TRK+
TRK–
2-AXIS
DEVICE
(TRACKING)
(FOCUS)
3
4
IN4R
IN4F
29
30
IN2F
IN2R
19
18
IN1F
IN1R
14
15
IN3F
IN3R
SPFD
SPRD
LEVEL SHIFT
IC306
92
91
88
89
86
85
83
APCREF
SFDR
SRDR
FFDR
FRDR
TFDR
TRDR
16PSB
PWM GENERATOR
AUTOMATIC
POWER
CONTROL
DIGITAL
SERVO
SIGNAL
PROCESS
7465647566 63
ANALOG MUX
A/D CONVERTER
AUTO
SEQUENCER
13
FROM CPU
INTERFACE
DIGITAL SERVO
SIGNAL PROCESSOR
IC301 (2/2)
RECP
PEAK HOLD
Q301
+3.3V
ABCD
AUX1 AUX2
ABCD
FE
TE
SE
PEAK
BOTM
81
80
82
XLRF
CKRF
DTRF
EFM/ACIRC
ENCODER/DECODER
SHOCK PROOF
MEMORY CONTROLLER
ATRAC
ENCODER/DECODER
PLL
FILTER
59
58
61
60
FILI
PCO
CLTV
FILO
100
EFMO 23 ADDT
IC301 (1/2)
15
TX
COMPA-
RATOR
51
52
55
ASYO
ASYI
RFI
ADIP
DEMODULATOR/
DECODER
78
ADFG
SPINDLE
SERVO
79 F0CNT
94 93
SPFD SPRD
SUBCODE
PROCESSOR
24
SAMPLING
RATE
CONVERTER
DIGITAL
AUDIO
INTERFACE 22
21
DIN
DOUT
DIGITAL SIGNAL PROCESSOR,
EFM/ACIRC ENCODER/DECODER,
SHOCK PROOF MEMORY CONTROLLER,
ATRAC ENCODER/DECODER, 2M BIT D-RAM
IC301 (1/2)
DADT
INTERNAL BUS
D-RAM
CLOCK
GENERATOR
2526 27
512FS
BUFFER
IC304
XBCK LRCK
FS256
BCK
LRCK
16
OSCI
512FS
17
OSCO
CPU
INTERFACE
MONITOR
CONTROL
10
XRST
12
DQSY
11
SQSY
14
XINT
9 8 5 6 7
SENS SRDT SWDT SCLK XLAT
LEVEL SHIFT
IC502
51331
61242
LEVEL SHIFT
IC503
1 2 3 4
MNT0 MNT1 MNT2 MNT3
13
1 3 5
12
2 4 6
FOK SHOCK XBUSY SLOCK
SWDT SCLK XLAT
59 62 55 54 52 45 51 64 26 27 28 29
MNT0 MNT1 MNT2 MNT3
21
LOCK
39
TEMP
MD-RST
SQSY
CC-XINT
SENS
MD-SI
MD-SO
MD-CKO
MD-LAT
7 6
EJECT LOAD
54
05
1 7
M
RIN FIN
OUT1 OUT2
LOADING
MOTOR DRIVE
IC305
M903
(LOADING)
63
C-SW
LOADING START/
EJECT END
E-SW LIMIT-IN
(LIMIT)
LOADING
END
ON: When the disc loading start
and the disc eject completion.
ON: When completion of
the disc loading.
ON: When the optical pick-up is
inner position.
31
32
EXTAL
XTAL
X501
10MHz
TH501
66
DEEMP
47, 46, 48, 49
1, 2, 24, 25
D0 – D3
32 – 29, 34 – 38, 43
9 – 12, 14 – 18, 5
A0 – A9
D0 – D3A00 – A09
41 22
45 3
44 4
42 23
XOE
XWE
XRAS
XCAS
OE
WE
RAS
CAS
D-RAM
IC307
(Page 22)
A
DADT, BCK, LRCK, 512FS
(Page 21)
C
LOCK
(Page 21)
B
EMPHASIS
MD MECHANISM CONTROLLER
IC501 (1/2)
• SIGNAL PATH
: MD PLAY
11 56
EMPHASIS

MDX-C8970
2020
4-2. BLOCK DIAGRAM – TUNER Section –
1
4
2FM-ANT
AM-ANT
6
VCO
11
AM-IF
5
5 24 14
169 10 13 12
120 70 71
28
32
VT
24
SSTOP SDA OSCI OSCO SCL
SSTOP
I2C-DATA
I2C-SCL
WIDE
117 46
VSM
(S-METER)
23
SD-IN
29
ST/MONO
118
AF-MUTE
FM IN
25
AM IN
1
LP FM
2
LP HC
3
LP AM
IF AM
21
FM-IF
15
IF FM
LP OUT
NARROW
13
SEEK
19
S-METER
20
SD
22
18
16
12
ST/MONO
FM LCH
FM RCH
AM DET
FILTER
X151
10.25MHz
FM/AM PLL
IC151
05
• SIGNAL PATH
: FM
: AM
MUTING
Q753
MUTING
Q752
MUTING
CONTROL SWITCH
Q751
R-CH MUTING
IC752
D751
D
(Page 21)
FM
E
(Page 21)
AM/TIR
FM/AM TUNER UNIT
TU101
MASTER CONTROLLER
IC500 (1/4)
LO/DX
LO/DX
FM/AM SIGNAL
METER BUFFER
Q133
SEEK
CN101
ANT 8
FM +B
FM B+
10
AM +B
AM B+
TUNER B+
9
+B (FM/AM)
WIDE/NARROW
SWITCH
Q132
31
R-CH
WIDE/NARROW
SWITCH
Q131
FORCED
6 5
3AUDIO +8.5V