Sony MDX-C7900 User manual

SERVICE MANUAL
MDX-C7900
FM/AM MINIDISC PLAYER
MDX-C7900R
FM/MW/LW MINIDISC PLAYER
US Model
Canadian Model
E Model
MDX-C7900
AEP Model
UK Model
MDX-C7900R
Model Name Using Similar Mechanism NEW
Base Mechanism Type MG-164KT-138
Optical Pick-Up Name KMS-241A/J2N
SPECIFICATIONS
MDX-C7900/C7900R
Refer to RM-X4S Service Manual (9-925-
698-[][]) issued previously for information
ofremotecommander(RM-X4S)supplied
with this set. Photo: MDX-C7900
– Continued on next page –
9-925-787-12 Sony Corporation
2001H0500-1 e Vehicle Company
C2001.8 ShinagawaTec Service Manual Production Group
Ver 1.1 2001.08

– 2 –
TABLE OF CONTENTS
1. SERVICE NOTE....................................................... 3
2. GENERAL
Location of Controls (MDX-C7900).............................. 4
Location of Controls (MDX-C7900R) ........................... 5
Resetting the Unit ........................................................... 6
Detaching the Front Panel............................................... 6
Preparing the Rotary Commander .................................. 6
Setting the Clock ............................................................. 6
Installation (US, Canadian) ............................................ 7
Installation (AEP, UK, E) ............................................... 8
Connections ..................................................................... 10
3. DISASSEMBLY ......................................................... 13
4. ELECTRICAL ADJUSTMENTS
Test Mode ........................................................................ 18
MD Section ..................................................................... 18
Tuner Section .................................................................. 18
5. DIAGRAMS
5-1. Block Diagram – SERVO Section – ............................... 21
5-2. Block Diagram – MAIN Section – ................................. 23
5-3. Block Diagram
– DISPLAY/KEY CONTROL Section –........................ 25
5-4. Block Diagram
– BUS CONTROL/POWER SUPPLY Section – ........... 27
5-5. Printed Wiring Boards
– MECHANISM DECK Section – ................................. 29
5-6. Schematic Diagram
– MECHANISM DECK Section – ................................. 31
5-7. Schematic Diagram – MAIN Section –.......................... 35
5-8. Printed Wiring Board – MAIN Section – ....................... 39
5-9. Printed Wiring Board – PANEL Section – ..................... 43
5-10. Schematic Diagram – PANEL Section – ........................ 45
5-11. IC Pin Function Description ........................................... 55
6. EXPLODED VIEWS................................................ 64
7. ELECTRICAL PARTS LIST ............................... 68
Ver 1.1

– 3 –
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 chip component replacement
• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
ATTENTION AU COMPOSANT AYANT RAPPORT
À LA SÉCURITÉ!
LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE !
SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE
DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIÈCES SONY DONT LES
NUMÉROS SONT DONNÉS DANS CE MANUEL OU
DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY.
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.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.
SECTION 1
SERVICE NOTE
•Type A/B Discrimination
[MAIN BOARD] (Component Side)
IC700
MB90574PFV-G-113-BND (C7900R: Type A)
MB90574PFV-G-114-BND (C7900: Type A)
MB90F574PFV-G-113 (C7900R: Type B)
MB90F574PFV-G-114 (C7900: Type B)

– 4 –
SECTION 2
GENERAL
This section is extracted from
instruction manual.

– 5 –

– 6 –

– 7 –

– 8 –

– 9 –

– 10 –

– 11 –

– 12 –

– 13 –
FRONT PANEL
COVER ASS’Y, PANEL (SUB) ASS’Y
Note: Follow the disassembly procedure in the numerical order given.
SECTION 3
DISASSEMBLY
1
Push the button (release).
2
3
Remove the front panel of the arrow.
3 four screws
(PTT2.6
× 6)
3 screw
(PTT2.6
× 6)
1
1
2 cover ass’y
4 panel (sub) ass’y

– 14 –
MECHANISM DECK (MG-164KT-138)
MAIN BOARD
1 two screws
(PTT2.6
× 4)
2 mechanism deck
(MG-164KT-138)
5 insulating sheet
4 main board
3 three screws
(PTT2.6
× 6) (ground point)
1 two screws
(PTT2.6
× 10)
2 heat sink
1 eight screws
(PTT2.6
× 10)

– 15 –
SERVO BOARD
FLOAT BLOCK
3 two screws
(BVTT2
× 4)
1 sensor flexible board
(CN102)
3 two screws
(BVTT2
× 4)
2 flexible board
(CN103)
4 servo board
3 spring (FL2
)
1 four screws
(BVTT2
× 4)
Release of the lock.
float block
A
5
Pushing an arrw A part, raise
the float block up ward at the
front to release a lock.
3 spring (FL2)
2 MD cover ass’y
4 two springs (FL)
lever (lock R)
lever (lock L)

– 16 –
OPTICAL PICK-UP (KMS-241A/J2N)
HOLDER ASS’Y
4 washer (M)
5 holder ass’y
1 spring (CHKG)
2 stop ring E (1.5)
3 lever (lock R)
3 lever (lock L)
2 stop ring E (1.5)
1 spring (CHKG
)
6 bearing (SL)
5 feed screw ass’
y
3 screw
(K2 × 3)
2 shaft (SL2)
1 two screws
(K2 × 3)
7 optical pick-up
(KMS-241A/J2N)
4 screw
(B2 × 3)

– 17 –
MOTOR ASS’Y (M901, M902, M903), SENSOR BOARD
1 Remove the solders
of motor (M901, M902, M903).
3 sensor board
2 two screws
(2
× 8)
8 base (SL)
7 screw
(B2
× 3)
6 motor ass’y
(M902)
5 bracket (SL)
4 screw
(P1.7
× 1.8)
!¡ screw
(P2
× 2.2)
!™ motor ass’y
(M903)
0 motor ass’y
(M901)
9 two screws
(P1.7
× 1.8)

– 18 –
SECTION 4
ELECTRICAL ADJUSTMENTS
TEST MODE
This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level andAM (MW)Auto Scan/Stop Level adjustments
can be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Set the “power select” switch (S700) is “A (ON)” position.
2. 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.
3. Push the preset [4] button.
4. Push the preset [5] button.
5. Press the preset [1] button for more than two seconds.
6. Then the display indicates all lights, the test mode is set.
<Release the Test mode>
1. Push the [OFF] button.
2. Return the “power select” switch (S700) to initially set posi-
tion.
MD SECTION
MD section adjustments are done automatically in this set.
TUNER SECTION
Note:
Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop LevelAdjustment.
2. FM Stereo Separation Adjustmnet.
3. AM (MW) Auto Scan/Stop LevelAdjustment.
4. RDS S-Meter 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
0 dB=1 µV
See the adjustment location from on page 20 for the ad-
justment.
Cautions during repair
When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.
3. 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.
Display
*1: MDX-C7900R is indicates “98.00”.
Adjustment Location: See page 20.
FM Stereo Separation Adjustment
Setting:
[SOURCE] button: FM
Procedure:
L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.
Specification: Separation more than 30 dB
Adjustment Location: See page 20.
FM RF signal
generator
Carrier frequency: 97.9 MHz (MDX-C7900)
98.0 MHz (MDX-C7900R)
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)
SHUF
REG
*1
SHUF
REG
*1
FM RF signal
generator
0.01 µ F
set
antenna jack (J1)
+
–
speaker out terminal
level meter
4
Ω
MDX-C7900 MDX-C7900R
Carrier frequency 97.9 MHz 98.0 MHz
Output level 60 dB (1 mV) 70 dB (3.2 mV)
Mode stereo stereo
main 1 kHz, 33.75 kHz 1 kHz, 20 kHz
deviation (45%) deviation (22.6%)
Modulation sub 1 kHz, 33.75 kHz 1 kHz, 20 kHz
deviation (45%) deviation (22.6%)
19 kHz 7.5 kHz 7.5 kHz
pilot deviation (10%) deviation (10%)
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.

RDS S-Meter Adjustment (MDX-C7900R)
Setting:
[SOURCE] button: FM
Procedure:
1. Set to the test mode. (See page 18.)
2. Push the [SOURCE] button and set to FM.
Display
3. Push the preset [10] button.
4. Adjust RV1 on MAIN board so that the display indication is
“15.8”.
Display
Specification: Display indication : 15.6 to 16.4
Adjustment Location: See page 20.
AM (MW) Auto Scan/Stop Level Adjustment
Setting:
[SOURCE] button (MDX-C7900): AM
[SOURCE] button (MDX-C7900R): MW
Procedure:
1. Set to the test mode. (See page 18.)
2. Push the [SOURCE] button and set to FM.
3. Push the [MODE] button and set to AM (MDX-C7900) or MW
(MDX-C7900R).
Display
4. Adjust with the volume RV1 on TU1 so that the “AM” or “MW”
indication turns to “AM0” or “MW0” indication on the dis-
play window.
But, in case of already indicated “AM0” or “MW0”, turn the
RV1 so that put out light “0” indication and adjustment.
Display
*2: MDX-C7900R is indicates “MW”.
*3: MDX-C7900R is indicates “999”.
Adjustment Location: See page 20.
– 19 – – 20 –
AM RF signal
generator
Carrier frequency: 1000 kHz (MDX-C7900)
999 kHz (MDX-C7900R)
30% amplitude
modulation by
1 kHz signal
Output level : 33 dB (44.7
µ V)
set
AM dummy antenna
(50 Ω )
30 Ω
15 pF
65 pF
antenna jack (J1)
SHUF
REG
*3
*2
TP
SHUF
REG
*3
*2
TP
FM RF signal
generator
Carrier frequency: 98.0 MHz
Output level : 35 dB (56.2
µ V)
Mode : mono
Modulation : no modulation
0.01 µ F
set
antenna jack (J1)
SHUF
REG
SHUF
REG
Adjustment Location:
– SET UPPER VIEW –
RV1 RDS S-METER Adjustment
TU1
RV1 AM (MW) AUTO SCAN/STOP LEVEL Adjustment
RV2 FM AUTO SCAN/STOP LEVEL Adjustment
RV4 FM STEREO SEPARATION Adjustment

MDX-C7900/C7900R
– 21 – – 22 –
5-1. 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-241A/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 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 OSC
IC304
XBCK
LRCK
FS256
BCK
LRCK
FS256
X301
22.5792MHz
16
OSCI
17
OSCO
CPU
INTERFACE
MONITOR
CONTROL
10
XRST
12
DQSY
11
SQSY
14
XINT
98 567
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
LOADING
END
LIMIT-IN
(LIMIT)
ON: When the disc loading start
and thedisc eject completion.
ON: When the optical pick-up is
inner position.
(ON: When completion of the disc loading.)
31
32
EXTAL
XTAL
X501
10MHz
TH501
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
A
DADT (Page 5)
(Page 5)
B
BCK, LRCK, FS256 (Page 5)
C
LOCK
MD MECHANISM CONTROLLER
IC501 (1/2)
• SIGNAL PATH
: MD PLAY
11 56
SECTION 5
DIAGRAMS