© 2001-11 PRINTED IN JAPAN
B51-7869-00 (N) 1940
CD RECEIVER
KDC-V7521/Y
SERVICE MANUAL
Escutcheon assy
(B07-3007-03)
Front glass
(B10-4161-01)
Panel assy
(A64-2582-02)
KDC-V7521/Y
This service manual does not include information on the CD mechanism assembly (exploded view, parts list,
schematic diagram or mechanism operation description).
For such information, please refer to the CD mechanism assembly service manual (X92-4030-0X, X92-4440-0X,
: B51-7867-00).
DC cord
(E30-4942-05): KDC-V7521Y
(E30-4956-05): KDC-V7521
Antenna adaptor
(T90-0523/0534-05)
Screw set
(N99-1704-05)
Lever
(D10-4562-04)
(D10-4621-04):KDC-V7521
Mounting hardware assy
(J21-9716-03)
Torsion coil spring
(G01-2924-04)
Plastic cabinet assy
(A02-1497-13)
Remote controller assy
(A70-2025-05)
Remote controller assy
(A70-0886-15)
KDC-V7521/
Y
2
BLOCK
DIAGRAM
PLL+B
FM+B
Q43,44
Q45,46
AM+B
DIMMER
MUTE
2WAY
DET.
ACC
BU DET.
A8V
A8V
Q4-6
IC3
Q9
Q7,8
Q10-13
SERVO AVR
SERVO+B
SW5V
Q3
Q50,51
Q30
Q1,2
SW5V
BU5V
BU5V
P CON
Q26-29
MUTE
IC8
Q32,33,35
DRIVER
MUTE
Q37-40
POWER IC
IC4
SYSTEM MI-COM
CD
CH
F/E
A1,Q53
E-VOL
IC2
PRE OUT
SP-OUT
DIMMER
TEL-MUTE
ACC
BACK UP
A-CONT
P-CONT
DECODER
RDS
IC1
IC14
Q52
EX.AMP CONTROL
ILLUM
+B
RESET
SW
RESET IC
IC16
IC2
IC1
IC3
Q3,4
Q5
LCD
DRIVER
REMO
G/R SW
V-I
CONVERTER
BUFFER
NOISE
Q36
OUTPUT VOLTAGE
CONTROL
EX.AMP
Q14
Q15
Q31
NAVI-MUTE
PANEL 5V
PANEL 5V
KEY
MATRIX
SW14V
SRM
MECHA.
SRM
DRIVER
MOTOR
(BACK LIGHT V-ILL)
LCD
ED1
CH
QUAL
SERVO+B
MUTE R
STOP
SW2
LO/EJ
MUTE L
RST
SW3
SW1
SDA
SCL
A8V
BU5V
SW5V
RST
REQ C
CLK
CH-CON
DATA H
REQ H
CD
AM
FM
P MUTE
MUTE
SW5V
PANEL5V
L
D
ATA
L
L
C
E
L
CLK
L
D
ATA
S
DA
SDA
DA
SCL
REMO
RESET
ILL+B
SRM
SW1
SRM
DET
SRM
SW2
SRM
SW3
SRM
SUB-
SRM
SUB+
RDCK
RDDA
QUAL
SDA
SCL
AFS
AFS
A8V
PLL DATA
PLL CLK
IFC OUT
S-METER
SW5V
SW5V
DATA C
BACK UP
BU5V
PANEL 5V
CHANGER
AM
FM
230mV
1200mV
1200mV
251mV
AUDIO OUT
NOISE
CD
3600mV
3600mV
855mV
1372mV
DRIVER
MUTE
MO SW
LCD
AVR
(X16- )
V-ILL
DAC
IC15
3
Ref.No.
Component name
Application/Function
Operation/Condition/Compatibility
IC1
LC75808W
LCD driver with key matrix
IC2
RS-171
Remote sensor IC
IC3
M62333FP
D/A converter
The brightness control of red, green and blue colour
Q1
DTA114EUA or KRA302
Key permission SW
For the key scanning start and the key detection SW
Q3
2SC4081
Red LED SW
When a base goes Hi, RED LEDs are turned on.
Q4
2SC4081
Green LED SW
When a base goes Hi, GREEN LEDs are turned on.
Q5
2SC4081
VLCD AVR
For LCD driver IC
Q6
DTA114EUA or KRA302
REMO SW
While a base goes Lo, PAN 5V is supplied to the
Remote sensor IC.
Q50-55
UMX2N
Constant current driver
The current control of red, green and blue LEDs
for the variable illumination
Q62
2SC4081
Buffer
The control voltage of the constant current driver
for red colour
Q63
2SC4081
Buffer
The control voltage of the constant current driver
for green colour
Q64
2SC4081
Buffer
The control voltage of the constant current driver
for blue colour
q ELECTRIC UNIT (X25-9392-7X, X25-8762-72)
Ref.No.
Component name
Application/Function
Operation/Condition/Compatibility
IC1
UPD703033GC139
System MI-COM.
IC2
TDA7407D
E. VOL & N.C. MPX IC
IC3
M5237ML
AVR IC
IC is combined with Q4, and it works as the error
detection, the driver.
IC4
TA8273H
Power IC
HD74HC02FP
IC8
or TC74HC02AF
Mute logic
2-input NOR x 4
or 74VHC02SJ
IC14
TDA7479D
RDS decoder
IC15
LB1930M
Motor driver IC
For SRM mechanism drive
IC16
S-80837ANNP
Reset IC
When BU 5V voltage is less than 3.7V, IC outputs Lo.
Q1
2SB1548 (P)
BU 5V AVR
While BACKUP is applied, AVR outputs +5V.
Q2
2SC4081 or 2SD1819A
Q1 and Q2 are inverted Darlington connection.
Q3
2SA1576A or 2SB1218A
SW 5V
While a base goes Lo, SW 5V is supplied to the
microprocessor peripheral circuits.
Q4
2SB1548 (P)
A8V AVR
Q4 is combined with IC3, and it outputs +8.3V.
Q5
DTC144EUA or UN5213
A8V AVR ON/OFF control
Q6
DTA124EUA or KRA303
A8V AVR SW
While Q5's base goes Hi, Q6 is turned on, and
A8V AVR is working.
Q7
DTA124EUA or KRA303
A8V AVR and SERVO +B AVR ON/OFF control
SW14V SW
While Q8's base goes Hi, Q7 is turned on, A8V
Q8
DTC144EUA or UN5213
AVR and SERVO +B AVR are working.
KDC-V7521/Y
COMPONENT DESCRIPTION
q SWITCH UNIT (X16-154X-XX, X16-1892-70)
4
KDC-V7521/Y
Ref.No.
Component name
Application/Function
Operation/Condition/Compatibility
Q9
2SD2375
SERVO +B AVR
When Q9's base goes Hi, SERVO +B AVR
outputs +7.6V.
Q10
2SB1184
While Q11's base goes Hi, AVR outputs +10.7V.
Q11
2SC4081 or 2SD1819A
ILL +B AVR
Works during POWER ON mode with a panel
attached to the set.
Q12
DTC144EUA or UN5213
ILL +B AVR ON/OFF control
Q13
DTA124EUA or KRA303
ILL +B SW
While Q12's base goes Hi, Q13 is turned on, and
ILL +B AVR is working.
Q14
DTA123JK or KRA105S
EXT. AMP CON. SW
When a base goes Lo, Q14 is turned on, and
control pulse waveform shape is outputted.
Q15
DTC144EUA or UN5213
Small lamp detection SW
When vehicle small lamps turn on, Q15 is turned
on .
Q26
2SB1277 (Q, R)
P-CON SW
When Q29's base goes Hi, Q26 is turned on .
Q29
DTC114YUA or UN5214
Works during POWER ON mode.
Q27
2SA1576A or 2SB1218A
P-CON. protection SW
Protect Q26 by turning ON when P-CON output
is grounded.
Q28
DTA124EUA or KRA303
P-CON. protection inhibit SW
Prevents Q27 tuning ON during start-up after
power ON.
While BACKUP is applied, a base goes Hi, and
Q30
2SC4081 or 2SD1819A
BU detection SW
Q30 is turned on.
When momentary power down has detected, a
base goes Lo, and Q30 is turned off.
Q31
2SC4081 or 2SD1819A
ACC detection SW
While ACC is applied, a base goes Hi, and Q31
is turned on.
Q32
DTA124EUA or KRA303
Mute driver for L Ch.
When BU detection SW or System RESET or MI-
Q33
DTA124EUA or KRA303
Mute driver for R Ch.
COM.'s Pre-mute is working, a base goes Lo,
and Q32 and Q33 are turned on.
Q35
DTC124EUA or UN5212
E. VOL mute SW
When BU detection SW or MI-COM.'s mute is
working, a base goes Hi, and Q35 is turned on.
Q36
2SC4081 or 2SD1819A
Noise buffer
Q37
DTC143TUA or KRC410
Audio mute SW (Front L)
When Q37's base goes Hi, Pre-output is muted.
Q38
DTC143TUA or KRC410
Audio mute SW (Front R)
When Q38's base goes Hi, Pre-output is muted.
Q39
DTC143TUA or KRC410
Audio mute SW (Rear L)
When Q39's base goes Hi, Pre-output is muted.
Q40
DTC143TUA or KRC410
Audio mute SW (Rear R)
When Q40's base goes Hi, Pre-output is muted.
Q43
DTC124EUA or UN5212
When Q43's base goes Hi, Q44 is turned on, and
Q44
2SB1277 (Q, R)
FM +B SW
A8V is supplied to the F/E.
Works during FM reception mode.
Q45
DTC124EUA or UN5212
When Q45's base goes Hi, Q46 is turned on, and
Q46
2SB1277 (Q, R)
AM +B SW
A8V is supplied to the F/E.
Works during AM reception mode.
Q50
DTC144EUA or UN5213
PAN 5V SW
While a panel is attached to the set, Q50 and Q51
Q51
2SA1576A or 2SB1218A
are turned on, and BU 5V is supplied to the panel.
Q52
2SC4081 or 2SD1819A
Composite signal output buffer
Q53
DTC144EUA or UN5213
IFC buffer
Waveform shaping
COMPONENT DESCRIPTION
5
KDC-V7521/Y
MICROCOMPUTER'S TERMINAL DESCRIPTION
Pin No.
Pin Name
I/O
Description
Processing Operation
1
AM+B
O
AM+B control
Hi : During AM reception
2
FM+B
O
FM+B control
Hi : During FM reception, Hi : During FM reception
if with RDS, RDBS
3
AFS
O
Noise detection time constant switching terminal
Hi : During FM reception, Lo : During FM seek or
AF search
4
PLL-DATA
I/O
Data input/output with F/E
5
PLL-CLK
I/O
Clock output to F/E
6
EVDD
-
Positive power supply connection terminal
Connected to BU 5V lines.
7
EVSS
-
Ground connection terminal
Connected to GND lines.
8
N.C.
O
Not used (N.C.)
9
BEEP
O
BEEP sound output
10
REMO
I
Data input from the remote control light sensor
11
PRE-MUTE L
O
Pre-out mute control (L)
When M MUTE L input is Lo during CD source
selected, PRE MUTE L outputs Lo.
12
PRE-MUTE R
O
Pre-out mute control (R)
When M MUTE R input is Lo during CD source
selected, PRE MUTE R outputs Lo.
13
IC2-SDA
I/O
Data line with IC2,CD mechanism MI-COM.
14
IC2-CLK
O
Clock line with IC2,CD mechanism MI-COM.
15,16
N.C.
O
Not used (N.C.)
17
DA-SDA / DIM-CON
O
Data output to D/A converter (V-LED model)
Data line with D/A converter
/ Dimmer control output
/ Hi : Dimmer OFF, Pulse wave shape : Dimmer ON
18
TEST
-
Test terminal
Not used (Connected to GND lines)
19
P-MUTE
O
Power IC mute control output
Lo : Mute (during POWER OFF, ALL OFF, TEL
MUTE)
20
P-STBY
O
Power IC standby control output
Lo : Power IC OFF, Hi : Power IC ON, ALL OFF
mode
21
MUTE
O
IC2 mute control output
OPEN (Hi) : Mute ON, Lo : Mute OFF
22,23
N.C.
O
Not used (N.C.)
24
ACC-DET
I
ACC detection terminal
Lo : ACC ON, Hi : ACC OFF
25
DIMMER
I
Small lights detection input
Lo : During vehicle small lamps turn on.
26
SW5V
O
SW 5V control output
Lo : POWER ON mode
Bass boost OFF__Hi : 160msec, Lo : 40msec
27
EXT-AMP-CONT
O
External amp. control output
Bass boost LOW__Hi : 130msec, Lo : 70msec
Bass boost HI__ Hi : 100msec, Lo : 100msec
28
P-CON
O
Power control output
Lo : POWER OFF mode, Hi : POWER ON mode
29
ANT-CON
O
Antenna control output
Hi : During TUNER mode or TI reception
30
P-ON
O
SW 14V control output
Hi : POWER ON mode
31
RESET
I
Reset input terminal
Lo : System reset
32
XT1
I
Sub clock resonator connection terminal
Clock count during POWER OFF mode
q IC1 (ELECTRIC UNIT : X25-9392-7X, X25-8762-72)