Sharp LC-20A2E User manual

LC-20A2E
S11O1LC-20A2E
LCD COLOURTELEVISION
SERVICE MANUAL
MODEL LC-20A2E
In the interests of user-safety (Required by safety regula-
tions in some countries) the set should be restored to its
original condition and only parts identical to those specified
be used.
Page
»IMPORTANT SERVICE SAFETY PRECAUTION................................................................................. 2
»ELECTRICAL SPECIFICATIONS......................................................................................................... 3
»OPERATION MANUAL ......................................................................................................................... 4
»OUTLINE DIMENSION FIGURE .......................................................................................................... 5
»REMOVING OF MAJOR PARTS .......................................................................................................... 6
»ADJUSTING PROCEDURE OF EACH SECTION ............................................................................... 9
»TROUBLE SHOOTING TABLE ........................................................................................................... 11
»CHASSIS LAYOUT ............................................................................................................................. 17
»BLOCK DIAGRAMS............................................................................................................................ 20
»DESCRIPTION OF SCHEMATIC DIAGRAM ..................................................................................... 24
»SCHEMATIC DIAGRAMS ................................................................................................................... 25
»PRINTED WIRING BOARD ASSEMBLIES ........................................................................................ 42
»PARTS LIST
ËELECTRICAL PARTS..................................................................................................................... 47
MAIN UNIT ..................................................................................................................................... 47
SUB UNIT....................................................................................................................................... 50
INVERTER UNIT............................................................................................................................ 52
SWITCH UNIT................................................................................................................................ 52
ËSUPPLIED ACCESSORIES PARTS.............................................................................................. 53
ËPACKING PARTS ........................................................................................................................... 53
ËCABINET PARTS LIST................................................................................................................... 53
ËCABINET AND MECHANICAL PARTS.......................................................................................... 54
»PACKING OF THE SET ...................................................................................................................... 55
CONTENTS
SERVICE MANUAL LCD COLOUR TELEVISION MODEL LC-20A2E
SHARP CORPORATION

LC-20A2E
9
ADJUSTING PROCEDURE OF EACH SECTION
[1] Entering the MAIN side adjustment process mode
There are three methods below.
1) Press the “Adjustment process key” on the remote control after turning on the power.
2) Pressing both the MENU key and the TV/VIDEO key on the main body, turn on the power.Then, press the volume
DOWN key and the tuning UP key at the same time.
3) Turn on the power with falling either KEY4 (pin 81 of microcomputer) or KEY5 (pin 82 of microcomputer) to “L”.
[Note] For the method 3), the ROM is initialized at the same time.Therefore, 3) must be executed if IC2004 or IC2001
is changed. For 1) or 2), the main body only enters the MAIN side adjustment process.
[2] Entering theTUNER side adjustment process mode
4) Entering the TUNER side adjustment process
MENU key on the main body →Tuning UP key (remote control) →Select the position shown in the figure below and
press the M key (remote control) within 1 second. →Enters the adjustment process.
[3] Adjustment
MAIN side adjustment (Press the “M” key to move the cursor and press the volume UP/DOWN key to make an
adjustment.)
• Power supply voltage adjustment (+B 5V)
• Model setting
• Inch size setting
• COMMON BIAS adjustment of LCD module
• CUTOFF adjustment
TUNER side adjustment (Press the tuning UP/DOWN key to move the cursor and press the volume UP/DOWN key to
make an adjustment.)
• Horizontal size adjustment (LCD adjustments)
• Video adjustment (other adjustments)
Y delay
Subcontrast
Subcolour
Subbrightness
Tint offset
AGC gain start
The TUNER side adjustment is possible.However, it is recommended to replace EAROM (I2).
Brightness
Contrast
Colour
: select M: Back
E: End
Direct control at TV

LC-20A2E
10
PAL/PAL60 SECAM NTSC
y delay 7 6 0
RF tint offset 0 0 0
sub contrast 2 2 0
sub colour 25 25 0
y delay 7 5 4
AV1/ tint offset 1 1 1
AV2 sub contrast 0 2 0
sub colour 30 30 20
y delay 7 5 1
AVS tint offset 1 1 1
sub contrast 0 0 0
sub colour 30 30 30
AGC gain start 27
3-1. +B adjustment
Page 9 of MAIN side adjustment process +B-ADJ
Adjust the voltage of the pin 12 of SC901 the SUB PWB to 5.0V±0.05V.
3-2. Model setting
Page 9 of MAIN side adjustment process MODEL
Set to A2E.
3-3. Inch size setting
Page 9 of MAIN side adjustment process INCH SIZE
Set to 20.
3-4. COMMON BIAS adjustment of LCD module
Page 9 of MAIN side adjustment process COM BIAS
Input the picture of gray scale and adjust it so as to obtain the best contrast.
3-5. CUTOFF adjustment
Page 9 of MAIN side adjustment process R CUTOFF, B CUTOFF
Adjust it so as to obtain the optimal colour balance.

LC-20A2E
11
TROUBLE SHOOTINGTABLE
No picture, No sound
Check all the settings microprocessor's adjust process menu.
Do F2, F3 and F4 function?
Are T701's secondary outputs, +38V, +16V, +9V, +5V and -8V normal?
Remove F2, F3 and F4 and check the load side. Is there short-circuiting?
Is there short-circuiting of T701 primary side periphery, Q751, Q753 and S4701.
Replace F2, F3 and F4.
Check S4701 and connection cable.
Is T701's primary oscillator waveform normal?
Check T701's secondary load.
Yes Yes
No
No No
No
Yes
Fluorecent lamp failure to light up
Does F1 function?
Is the pin 34 of IC1201 in the "H" state?
Is the Q3603 short-circuiting?
Is there short-circuiting of T7751~7756 primary side periphery, Q7751~Q7755.
Yes
Yes
No
No
No
Yes
Replace the fluorecent lamp with new one and check again.
Yes
Check the OFL1 line, IC1201 and their peripheral parts.
Check Q3603 and their peripheral parts.
Check T7751~T7756, Q7751~Q7755 and connection cable.

LC-20A2E
12
TROUBLE SHOOTINGTABLE (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is in/output of IC801 normal?
Is in/output of IC1201 normal?
Check IC801 and its peripheral parts.
Check IC1201 and its peripheral parts.
Check IC402 and its peripheral parts.
Check IC801, AV1 line and its peripheral parts.
Check LCD panel voltages and waveform.
Yes
Yes
No
No
No picture at all
Is in/output of IC402 normal?
Is input at pin 73 of IC801 normal?
Yes
No
No
No TV and VIDEO 1 output
Is voltages at pin 3 of W7 and pins 3, 4, 5 of W14 tuner normal?
Is output at pin 2 of W7 tuner normal?
Check the power line.
Check tuner and its peripheral parts.
Is input at pin 3 of IC402 normal?
Is the pins 2 and 4 of IC402 at "H" and "L" state?
Yes
Yes
No
No
No
No
No
Yes
No TV output
Is the pins 65 and 66 of IC2001 at "H" and "L" state?
Yes
Check the its line. Check the its line.
Check IC402 and its peripheral parts.
Is input at pin 1 of IC402 normal?
Is the pins 2 and 4 of IC402 at "L" state?
Check the its line. Check the its line.
Check IC402 and its peripheral parts.
Is the pins 65 and 66 of IC2001 at "L" state?
Yes
Yes
No
No No
No VIDEO 1 output

LC-20A2E
13
TROUBLE SHOOTINGTABLE (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is input at pin 74 of IC801 normal?
Check the AV2 line and their peripheral parts.
Check the SC2001, SY-line, SC-line and their peripheral parts.
No
No VIDEO 2 output
Is input at pins 71 and 72 of IC801 normal?
No
No S-VIDEO output
Is input at pin 70 of IC801 normal?
Check the V2VO line and their peripheral parts.
No
No line output
Is input at pins 1, 2, 3, 56, 57 and 79 of IC801 normal?
Is output at pins 11, 13 and 16 of I4 normal?
Check IC801 and their peripheral parts. Check I13 and their peripheral parts. Check I9 and their peripheral parts.
Check I4 and their peripheral parts.
Is output at pins 11, 13 and 16 of I13 normal?
Yes
Yes
No
No No
No TELETEX output
Is output at pins 44~49 of I9 normal?
Yes
No

LC-20A2E
14
TROUBLE SHOOTINGTABLE (Continued)
No picture
Check all the settings microprocessor's adjust process menu.
Is source GND normal?
Is CSCOM waveform normal?
Check R1212, FB1201 and their peripheral parts.
Check IC1109, Q1101, Q1102, D1101, R1120, R1130 and their peripheral parts.
Check R1231 and their peripheral parts.
Yes
No
No
Becomes dark
No
Time passes, becomes dark
Is gate GND normal?
Is gate clock (GCK) normal? Is output at pin
3 of IC1205 normal?
Yes
No
Check D1201 and their peripheral parts.
No
Is B-5.5V being outputted?
Is VCC being outputted?
Check T701's secondary +5V outputs line?
Yes
No
Is GSP waveform normal?
Check R1223 and gate aray peripheral parts.
Yes Yes
No
Check R1223 and their peripheral parts.
Becomes white.
Is 3.3V VHS being outputted?
Is source clock (CK) normal?
Check +3.3V outputs line of IC752.
Check R1210, R1211 and their peripheral parts.
Check FB1203 and gate aray peripheral parts.
Is output of LBR and HG normal?
Yes
Yes
No
No
No
Vertical line output
No picture
Check all the settings microprocessor's adjust process menu.
Is output of R0~R5 normal? Is output of G0~G5 normal? Is output of B0~B5 normal?
Check R1202, R1203 and their peripheral parts.
Check R1204, R1205 and their peripheral parts. Check R1206, R1207 and their peripheral parts.
Check T701's secondary +5V outputs line.
Yes
Yes
No
No
Colour is unusual
Is VLS 5V being outputted?
No
Picture image is gloomy
Is in/output of SPIO and SPOI normal?
Check R1209 and their peripheral parts.
No
No picture image inversion
Is output V0, V16, V32, V48 and V63 normal?
Check IC1106, IC1107, IC1108 and their peripheral parts.
No
Gradation defect
Is output of U/D normal? Check Q1201
and their peripheral parts.
Yes
No

LC-20A2E
15
TROUBLE SHOOTINGTABLE (Continued)
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 3 and 5 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 their peripheral parts. Check IC903 and their peripheral parts.
Check IC303 and their peripheral parts.
Check IC3305 and their peripheral parts.
Check front speaker and connection cable.
Yes
Is the pin 53 of IC2001 in the "L" state?
Is output at pins 24 and 25 of IC901 normal? Is output at pins 1 and 7 of IC304 normal?
Yes
Yes
No
No
No
No
No
Is output at pins 42 and 43 of SC402 normal?
Yes
Is output at pins 6 and 7 of P4004 normal?
Yes
Muting effect is on. Check the FSMUTE line.
Check IC901 and their peripheral parts. Check IC304 and their peripheral parts.
Check SC402, SC901 and their peripheral parts and connection.
Check P4004 and their peripheral parts and connection cable.
Yes
Check the J4001 line.
No sound from headphone
Is output at pins 36 and 37 of IC901 normal?
Is output at pins 1 and 7 of IC902 normal?
Check IC901 and their peripheral parts. Check IC902 and their peripheral parts.
Yes
Yes
No
No
No sound from output line
TV sound failure
Is output at pins 15 and 16 of SC402 normal?
Is output at pins 17 and 18 of W9 normal?
Check SC402, SC901 and their peripheral parts and connection. Check W9 and their peripheral parts and connection.
Yes
No
No
Check the U1 line.
Yes
Is output at pin 1 of W7 tuner normal?
Is input at pin 67 of IC901 normal?
Check the tuner and their peripheral parts. Check IC901, MONOS/SIF line and their peripheral parts.
Yes
No
No

1234567891011 12 13 14 15 16 17 18 19 20
A
B
C
D
E
F
G
H
I
J
LC-20A2E
LC-20A2E
BLOCK DIAGRAMS
LAMP
T7751~T7756
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 DC13V
ANALOG MULTIPLEXER
IC1205
L/R
REVERSE
IC303
FIFO
IC1202
LPF
IC903
AUDIO
AMPLIFER
IC304
LCD
CONTROLLER
IC1201
OFL1
DC/AC
INVERTER
DRIVE
Q3603
Q7751~Q7755
INV VCC
INV
DC13V
KEY
REMOTE CONTROL
RECEIVER
RESET
IC2002
CS
E2PROM
IC2004
I2C
I2C
I2C
I2C
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
I2C bus
S INPUT
AV2 INPUT
AV1
INPUT/
OUTPUT
TUNER
INPUT
HEAD PHONE
OUTPUT
AV
OUTPUT
P901
OSDHD
SCL, SDA
V1 SC
V1 V
DY
V1 L/R
V2 VO
V2 LO/RO
V2 V
V2 L/R
TV V
SIF
SC2 OUT L/R
DACA_L/R
P2003
SC2001
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
I2C
ËMAIN BLOCK DIAGRAM
20~21

1234567891011 12 13 14 15 16 17 18 19 20
A
B
C
D
E
F
G
H
I
J
LC-20A2E
LC-20A2E
ËTUNER BLOCK DIAGRAM
I2C bus
S INPUT
AV2 INPUT
AV1
INPUT/
OUTPUT
TUNER
INPUT
HEAD PHONE
OUTPUT
AV
OUTPUT
S INPUT
AV2 INPUT
AV1
INPUT/
OUTPUT
ANT
INPUT
HEAD PHONE
JACK
AV
OUTPUT
SCL, SDA
C IN VPC
H
V
R_VPC, G_ VPC, B_VPC
SUBCLK
SUBIN
SUBOUT
M/S IN
M/S OUT
V IN2 VPC
DY
SC1 IN L/R MSP
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
DACA_L/R
W9
I2C
I2C
I2C
OSD
W1
DC 13V
W13
ANALOG SWITCH
I4
MICON
I9
ANALOG SWITCH
I13
R_OSD, G_OSD, B_OSD
H
V
HEAD PHONE AMP
Q18~Q23
TUNER
W7, W14
HEAD PHONE SOUND(L/R)
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
AV2 SOUND(L/R)
AV2 PICTURE
S PICTUTE(Y)
S PICTURE(C)
I2C
I2CE2PROM
I2
ROM
I3
MEMORY
I6
W4
DC JACK
W17
W5
W11
W6
U1
W10
W3
W16
22~23