© 1999-12 PRINTED IN JAPAN
B51-7576-00 (N) 1789
CASSETTE RECEIVER
SERVICE MANUAL
KRC-108S/188
KRC-108S
KRC-188
Knob (EJECT)
(K27-3554-03)
Escutcheon
(B07-2181-02)
LCD
(B38-1024-05)
Panel
(A64-1932-02)
Cassette lid
(A53-1675-03)
Knob (REW)
(K27-3556-04)
Knob (FF)
(K27-3555-04)
Knob (EJECT)
(K27-3554-03)
Lever
(D10-3031-04)x2
Mounting hardware
(J21-9491-03)
DC cord
(E30-4783-05) : KRC-108S
(E30-4784-05) : KRC-188
Stay
(J54-0606-04)
Screw set
(N99-1632-05)
Escutcheon
(B07-2181-02)
LCD
(B38-1024-05)
Panel
(A64-1933-02)
Cassette lid
(A53-1677-03)
Knob (REW)
(K27-3556-04)
Knob (FF)
(K27-3555-04)
KRC-108S
KRC-188
2
BLOCK DIAGRAM ........................................................................................ 3
MICROCOMPUTER'S TERMINAL DECRIPTION ........................................ 4
ADJUSTMENT ............................................................................................. 6
PC BOARD .................................................................................................... 7
SCHEMATIC DIAGRAM ............................................................................. 11
EXPLODED VIEW ....................................................................................... 15
PARTS LIST ................................................................................................ 17
SPECIFICATIONS .................................................................... BACK COVER
CONTENTS
KRC-108S/188
KRC-108S/188
3
BLOCK DIAGRAM
IC1
KEY
MUTE
B
.U
DET
.
B.
U
AC
C
P-CONT
.
MUTE
PRE
PO
WER
IC
EQ.
AMP
AMP
NC/MPX
E-V
OL.
FR
ONT
Lch
FR
ONT
Rch
REAR
Lch
REAR
Rch
J2
LED
T
APE
MECHA
MAIN
IC5
1
Lch
2
Rch
PRE
OUT
IC2
IC4
IC3
SP
OUT
REAR
RST
SW
RST
IC
PST9130NR
IC6
A
CC
DET
.
P-CONT
.
ANT
-CONT
J2
J5
HD74HC27FP
40W
TD
A7384A
FM+B
Q201
AM+B
Q203
5V
AM
BPF
FM
BPF
Q450,451
Q62
Q50
Q350
Q53
SW5V
Q56
8V
Q60
ILLUMI
B
U5V
Q51
SYSTEM
u-COM
TD
A7400D
RST
Q370
ANT
-CONT
LA3161
M38258MCD
FP
7SEG
LCD
ED1
FM
ANT
AM
ANT
RF
GND
FM+B
AM+B
OSC
GND
OSC
GND
OSC
GND
VT
PLL
+B
IFC
OUT
SD
A
SCL
DIG
GND
IF1+B
IF1
GND
S-METER
IF2
GND
SD
FM+B
PON
A
CC
DET
B
.U
DET
SCL
MUTE
SD
A
P
CON
RESET
FWD/REV
MOTO
R
Rch
COM
Lch
T
APE
MP
IN
AM
MPX
OUT
RR
OUT
LR
OUT
RF
LEVEL
SCL
SD
A
OUT
LF
STBY
MUTE
Rch
Lch
T
-MUTE
FWD
REV
B.
U
SMUTE
9
(FF/REW)
B
U5V
AM+B
VDD
5V
P A
CKIN
ANT
CON
BEEP
SVR
AMP
.STBY
SVR
A
C
GND(BEEP)
Rch
Lch
T
APE
:1681mV
AM
:546mV
FM
:1781mV
8V
RF
GND
OSC
GND
IF2
+B
A
UDIO
OUT
8V
S-METER
SD
PLL-SCL
PLL-SD
A
HEAD
R
55.6mV
B
U5V
B.
U
.5
V
8V
B
U5V
AM:
170mV
FM:
400mV
L
PA
C
K
IN
PLA
Y
FF/REW
ILL
9
KS0-KS4
KI0-KI3
25
25
SEG1-SEG22
COM1-COM3
AMP
.MUTE
8V
B
U5V
(X13)
M
F/E
KRC-188
ONL
Y
KRC-108S/188
MICROCOMPUTER'S TERMINAL DESCRIPTION
4
Microcomputer (M38258MCD066FP : IC1 : X14)
·Terminal description
Pin No.
Pin Name
I/O
Signal
Description
Logic
1
C1
I
(NC)
Not used.
2
VL1
I
VL1
LCD power input.
3-5
P67-65
I
KI0-2
Key return input.
6-9
P64-61
O
KS0-3
Key scan output.
10
ANO
I
SMETER
Signal meter.
11
P57
O
KS4
Key scan output.
12
TOUT
O
BEEP
Beep output.
13
P55
O
(NC)
Not used.
14
P54
O
MOTOR
Mechanism motor ON/OFF.
H: ON
15
P53
I
FF/REW
Mechanism FF/RWD detection.
L: Detected.
16
P52
I
PACK_IN
Mechanism cassette pack-in detection.
H: Detected.
17
P51/INT3
I
KI3
Key return input.
18
P50
I
FWD/REV
Mechanism play direction detection.
H: FWD
19-25 P47-41
O
(NC)
Not used.
26
P40
I
SD
Station detection.
H: Station detected.
27
P77
O
PLL_CLK
IC3 clock output.
28
P76
I/O
PLL_DATA
IC3 data input/output.
29
P75
I
IFC
AM bandwidth.
H: Station detected.
30
P74
O
AM+B
AM power output.
H: ON
31
P73
O
FM+B
FM power output.
H: ON
32
P72
O
SCK
IC2 clock output.
33
P71
I/O
SDA
IC2 data input/output.
34
P70
O
(NC)
Not used.
35
RESET
I
RESET
Reset input.
36,37 P81,80
O
(NC)
Not used.
38
XIN
-
X_IN
Clock input.
39
XOUT
-
X_OUT
Clock output.
40
Vss
-
Vss
Power input (0 V).
41
P27
I
IC2_TYPE1
IC2 constant switching.
42
P26
I
IC2_TYPE2
IC3 constant switching.
43
P25
O
(NC)
Not used.
44
P24
I
SEL1
Destination type switching.
45
P23
I
SEL2
Destination type switching.
46
P22
O
MUTE
Muting ON/OFF.
H: MUTE
47
P21
O
STBY
Power IC standby control.
H: ON
48
P20
O
SVR
Power IC SVR control.
H: OFF
49
P17
I
ACC_DET
Acc detection.
H: ACC OFF
50
P16
I
BU_DET
Momentary power down detection.
H: Power down.
KRC-108S/188
5
Pin No.
Pin Name
I/O
Signal
Description
Logic
51
P15
O
P_MUTE
Power IC muting control.
H: Power down.
52
P14
O
ANT_CON
External antenna control.
H: ON
53
P13
O
P_CON
Power control output.
H: ON
54
P12
O
ILLUM_ON
Illumination control.
H: ON
55
P11
O
(NC)
Not used.
56
P10
O
SW5
5V power control.
L: ON
57
P07
O
EQ_MUTE
Equalizer muting.
H: MUTE
58-64 P06-00
O
(NC)
Not used.
65,66 P37,36
O
(NC)
Not used.
67,68 SEG23,22
O
(NC)
Not used.
69-90 SEG21-0
O
SEG22-1
LCD segment output.
91
Vcc
-
Vcc
Power input (5 V).
92
VREF
-
VREF
A/D reference voltage input.
93
Avss
-
Avss
Analog power input (Vss).
94
COM3
O
(NC)
Not used.
95
COM2
O
COM3
LCD common output.
96
COM1
O
COM2
LCD common output.
97
COM0
O
COM1
LCD common output.
98
VL3
I
VL3
LCD power input.
99
VL2
I
VL2
LCD power input.
100
C2
I
(NC)
Not used.
MICROCOMPUTER'S TERMINAL DESCRIPTION
How to Read the Destination Type
The destination type is set by reading the following microcomputer ports at
the time of reset-start of the microcomputer.
Once the destination type is read and set during the microcomputer
resetting, any change in the ports during the microcomputer operation will
be ignored.
Destination Type
SEL1
SEL2
KL
L
ML
H
JH
X
X: don't care