Sharp LC-20B2E (serv.man9) Service Manual ▷ View online
17
LC-20B2E
No sound
Check all the settins microprocessor's adjust process menu.
Is the pin (53) of
IC2001 in the
"L" state?
Is output at pins
(26) and (27) of
IC901 normal?
Is output at pins
(1) and (7) of
IC903 normal?
Yes
Yes
No
No
No
No
No
No sound
from front
speakers
Is output at pins
(1) and (7) of
IC303 normal?
Yes
Is output at pins
(8) and (12) of
IC3305 normal?
Yes
Muting effect is
on. Check the
FSMUTE line.
Check IC901
and its
peripheral parts.
Check IC903
and its
peripheral parts.
Check IC303
and its
peripheral parts.
Check IC3305
and its
peripheral parts.
Check front
speaker and
connection
cable.
Yes
Is the pin (53) of
IC2001 in the
"L" state?
Is output at pins
(26) and (27) of
IC901 normal?
Is output at pins
(1) and (7) of
IC903 normal?
Yes
Yes
No
No
No
No
No
No
Is output at pins
(1) and (7) of
IC303 normal?
Yes
Is output at pins
(8) and (12) of
IC3305 normal?
Yes
Muting effect is
on. Check the
FSMUTE line.
Check IC901
and its
peripheral parts.
Check IC903
and its
peripheral parts.
Check IC303
and its
peripheral parts.
Check IC3305
and its
peripheral parts.
Yes
Is output at
Q301 normal?
Check Q301
and connection
cable.
No sound
from
headphone
TV sound
failure
Is output at pins
(37) and (38) of
IC901 normal?
Is output at pins
(1) and (7) of
IC902 normal?
Check IC901
and its
peripheral parts.
Check IC902
and its
peripheral parts.
Yes
No
No
No
No sound
from output
line
Is output at pin
(1) of W7 tuner
normal?
Is input at pin
(67) of IC901
normal?
Check the tuner
and its
peripheral parts.
Check IC901,
MONOS/SIF
line and their
peripheral parts.
Yes
No
TROUBLE SHOOTING TABLE
(Continued)
19
LC-20B2E
18
12
11
10
9
8
7
6
5
4
3
2
1
A
B
C
D
E
F
G
H
JACK Unit
INVERTER-A Unit
INVERTER-B Unit
OPERATION Unit
R/C RECEIVER Unit
TUNER Unit
CHASSIS LAYOUT
MAIN Unit (Side A)
MAIN Unit (Side B)
21
LC-20B2E
20
12
11
10
9
8
7
6
5
4
3
2
1
A
B
C
D
E
F
G
H
BLOCK DIAGRAM
Ë
TUNER Block Diagram
I
2
C bus
AV1
INPUT/
OUTPUT
TUNER
INPUT
AV
OUTPUT
AV1
INPUT/
OUTPUT
ANT
INPUT
AV
OUTPUT
SCL, SDA
H
V
R_VPC, G_ VPC, B_VPC
SUBCLK
SUBIN
SUBOUT
M/S IN
M/S OUT
V OUT VPC
SC1 OUT L/R MSP
V IN3 VPC
SC2 IN L/R MSP
V IN2 VPC
AN IN1 MSP
SC2 OUT L/R MSP
SC902
I
2
C
I
2
C
I
2
C
OSD
SC802
DC 13V
SIG Vcc
INV Vcc
PA Vcc
HR
HL
P904
ANALOG SWITCH
I4
MICON
I9
ANALOG SWITCH
I13
R_OSD, G_OSD, B_OSD
H
V
TUNER
W7, W14
SOUND(L/R)
RF
AV1 SOUND(L/R)
AV1 PICTURE
R_SCART, G_SCART, B_SCART
AV1 SOUND OUTPUT(L/R)
AV1 PICTURE OUTPUT
SCL, SDA
I
2
C
I
2
C
E
2
PROM
I2
ROM
I3
MEMORY
I6
DC JACK
HEADPHONE
JACK
J3702
SC903
J902
J903
23
LC-20B2E
22
12
11
10
9
8
7
6
5
4
3
2
1
A
B
C
D
E
F
G
H
Ë
MAIN Block Diagram
LAMP
T5701~T5702
DC/AC
TRANCE
LAMP ERROR
DET
L_ERR
COMMON DRIVE
IC1109
CSCOM
LCD
PANEL
V0,V16,V32
V48,V64
DAC
IC1101
MP_CLK, MPDA, DAC1CS
CS
GRADUATION
POWER FOR
LCD
IC1102~IC1108, IC1110
R0~R5, G0~G5, B0~B5, CK
FRONT SPEAKER
L/R
FLSP
FRSP
GCK
PA VCC
AUDIO
AMPLIFER
IC3305
PA DC12V
ANALOG MULTIPLEXER
IC1205
L/R
REVERSE
IC303
FIFO
IC1202
LPF
IC903
AUDIO
AMPLIFER
IC304
LCD
CONTROLLER
IC1201
OFL1
DC/AC
INVERTER
DRIVE
Q3603
Q5701~Q5703
INV VCC
INV
DC12V
KEY
REMOTE CONTROL
RECEIVER
RESET
IC2002
CS
E
2
PROM
IC2004
I
2
C
I
2
C
I
2
C
I
2
C
MICON
IC2001
MP_CLK, MPDA, DAC1CS
CONTROL SIGNAL
LLC1, LLC2, FIELD
VSY
HSY
UV0~UV7, VP_Y0~VP_Y7
DACM_L/R
DACA_L/R
MSP
IC901
VPC
IC801
HSY
ANALOG
SWITCH
IC2007
HSY2
HD
CSYNC
+5V
+31V
+14V
+8V
+38V
+16V
+9V
+5V
-8V
+3.3V
+3.3V REG
IC752
IC201
Q204
Q202
Q203
+5V REG IC751
DC/DC
T701
PWM
IC702
INV DC 13V
PA DC 13V
PA VCC
INV VCC
SIG VCC
DC 13V
OSD
S INPUT
AV2 INPUT
AV1
INPUT/
OUTPUT
TUNER
INPUT
HR
HL
AV
OUTPUT
P901
OSDHD
V1 SC
V1 SY
V1 IN
V1 L/R
V2 VO
V2 LO/RO
V2 V
V2 L/R
TV V
SIF
SC2 OUT L/R
SC902
J5001
SC5001
OSDVD
OSDR, OSDG, OSDB
SUBCLK, SUBIN, SUBOUT, M/S IN, M/S OUT
SC801
CSYNC
SYNC SEPARATE
IC401
SC
AV3
VO
AV2
AV1
BUFFER
IC902
TV/AV
SELECTION
IC402
I
2
C bus
SCL, SDA
I
2
C
P2004
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