LC-20A2M LCD COLOUR TELEVISION CONTENTS Page Page » IMPORTANT SERVICE SAFETY PRECAUTION ...... 2 » SPECIFICATIONS ............................................. 3 » OPERATION MANUAL ...................................... 4 » DIMENSIONS .................................................... 5 » REMOVING OF MAJOR PARTS ....................... 6 » TROUBLE SHOOTING TABLE .......................... 9 » ADJUSTMENT PROCEDURE ......................... 12 » CHASSIS LAYOUT .......................................... 14 » BLOCK DIAGRAM ........................................... 16 » DESCRIPTION OF SCHEMATIC DIAGRAM .. 18 » SCHEMATIC DIAGRAM .................................. 19 » PRINTED WIRING BOARD ASSEMBLIES ..... 29 SHARP CORPORATION SERVICE MANUAL In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used. MODEL LC-20A2M Example of suffix symbol: The component parts of this model are partially different depending on their suffix symbols. Before servicing the units, be sure to check the suffix symbol on the model label that is applied on the back of the unit. LCD COLOUR TV MODEL LC-20A2M 13V 3.7A, 48W SERIAL NO. SHARP CORPORATION MADE IN JAPAN N1 X xxxxxxxxx Suffix "X" for Australlia » PARTS LIST Ë ELECTRICAL PARTS .................................. 34 MAIN UNIT .................................................. 34 Y/C SEPARATION UNIT .............................. 38 TERMINAL UNIT ......................................... 40 INVERTER UNIT ......................................... 41 OPERATION UNIT ....................................... 42 Ë CABINET AND MECHANICAL PARTS ....... 42 Ë SUPPLIED ACCESSORIES ........................ 44 Ë PACKING PARTS ......................................... 44 » PACKING OF THE SET ................................... 45 TENTATIVE
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1
LC-20A2M
LCD COLOUR TELEVISION
CONTENTSPage Page
» IMPORTANT SERVICE SAFETY PRECAUTION ...... 2» SPECIFICATIONS ............................................. 3» OPERATION MANUAL ...................................... 4» DIMENSIONS .................................................... 5» REMOVING OF MAJOR PARTS ....................... 6» TROUBLE SHOOTING TABLE .......................... 9» ADJUSTMENT PROCEDURE......................... 12» CHASSIS LAYOUT .......................................... 14» BLOCK DIAGRAM ........................................... 16» DESCRIPTION OF SCHEMATIC DIAGRAM .. 18» SCHEMATIC DIAGRAM .................................. 19» PRINTED WIRING BOARD ASSEMBLIES ..... 29
SHARP CORPORATION
SERVICE MANUALS00K2LC-20A2H
In the interests of user-safety (Required by safety regulations in some countries) the set should be restoredto its original condition and only parts identical to those specified should be used.
MODEL LC-20A2M
Example of suffix symbol:
The component parts of this model are partially differentdepending on their suffix symbols. Before servicing the units,be sure to check the suffix symbol on the model label that isapplied on the back of the unit.
LCD COLOUR TVMODEL LC-20A2M13V 3.7A, 48W
SERIAL NO.SHARP CORPORATIONMADE IN JAPAN
N1
X x x x x x x x x x
Suffix "X" for Australlia
» PARTS LISTË ELECTRICAL PARTS .................................. 34
MAIN UNIT .................................................. 34Y/C SEPARATION UNIT .............................. 38TERMINAL UNIT ......................................... 40INVERTER UNIT ......................................... 41OPERATION UNIT....................................... 42
Ë CABINET AND MECHANICAL PARTS ....... 42Ë SUPPLIED ACCESSORIES ........................ 44Ë PACKING PARTS ......................................... 44
» PACKING OF THE SET ................................... 45
TENTATIVE
2
LC-20A2M
CAUTION: FOR CONTINUED PROTECTIONAGAINST A RISK OF FIRE REPLACE ONLY WITHSAME TYPE FUSE. F3701 (2.0A, 250V), F3702(2.5A, 250V), F7751 (5.0A, 250V) FUSE.
Many electrical and mechanical parts in LCD televisionhave special safety-related characteristics.These characteristics are often not evident from visualinspection, nor can protection afforded by them benecessarily increased by using replacement componentsrated for higher voltage, wattage and etc.Replacement parts which have these special safetycharacteristics are identified in this manual; electricalcomponents having such features are identified by “ å”
IMPORTANT SERVICE SAFETY PRECAUTIONË Service work should be perfomed only by qualified service technicians who are thoroughly
familiar with all safety checks and the servicing guidelines which follow:
and shaded areas in the Replacement Parts Lists andSchematic Diagrams.For continued protection, replacement parts must beidentical to those used in the original circuit.The use of a substitute replacement parts which do nothave the same safety characteristics as the factoryrecommended replacement parts shown in this servicemanual, may create shock, fire or other hazards.
WARNING
1. For continued safety, no modification of any circuitshould be attempted.
2. Disconnect AC power before servicing.
BEFORE RETURNING THE RECEIVER(Fire & Shock Hazard)
Before returning the receiver to the user, performthe following safety checks:
1. Inspect all lead dress to make certain that leads arenot pinched, and check that hardware is not lodgedbetween the chassis and other metal parts in thereceiver.
2. Inspect all protective devices such as non-metalliccontrol knobs, insulation materials, cabinet backs,adjustment and compartment covers or shields,isolation resistor-capacitor networks, mechanicalinsulators and etc.
3. To be sure that no shock hazard exists, check forleakage current in the following manner.
• Plug the AC cord directly into a 110~240 volt AC outlet,and connect the DC power cable into the receiver'sDC jack. (Do not use an isolation transformer for thistest).
• Using two clip leads, connect a 50k ohm, 10 watt resistorparalleled by a 0.15µF capacitor in series with allexposed metal cabinet parts and a known earth ground,such as electrical conduit or electrical ground connectedto an earth ground.
• Use an AC voltmeter having with 5000 ohm per volt, orhigher, sensitivity or measure the AC voltage dropacross the resisor.
• Connect the resistor connection to all exposed metalparts having a return to the chassis (antenna, metalcabinet, screw heads, knobs and control shafts,escutcheon and etc.) and measure the AC voltage dropacross the resistor.All checks must be repeated with the AC cord plugconnection reversed. (If necessary, a nonpolarizedadaptor plug must be used only for the purpose ofcompleting these checks.)Any reading of 35V peak (this corresponds to 0.7milliamp. peak AC.) or more is excessive and indicatesa potential shock hazard which must be correctedbefore returning the monitor to the owner.
TO EXPOSEDMETAL PARTS
CONNECT TOKNOWN EARTHGROUND
DVMAC SCALE
50k ohms.10W
0.15 µFTEST PROBE
3
LC-20A2M
Specifications
4
LC-20A2M
Operation Manual
Main unit (front view)
Remote control
Main unit (rear view)
5
LC-20A2M
Dimensions
(Unit: mm)
6
LC-20A2M
REMOVING OF MAJOR PARTS1. Detach the terminal cover.2. Remove the four lock screws from the table stand.3. Remove the four lock screws each from the left and right speakers. Disconnect the connectors
and detach the speaker assemblies.4. Remove the ten lock screws from the terminals.5. Remove the five lock screws from the cabinet B.6. Undo the nine hooks off the cabinet B: Press the hook 6-1 first and then the hooks 6-2 thru
6-9 in this order. Detach the cabinet B.7. Undo the six wire holders and peel off the 9 pieces of tape. Disconnect the connection
cables.(Note: Some pieces of tape are located below the PWBs. To access such tape, detach the
PWBs, peel off the tape and disconnect the cables.)8. Disconnect the connectors from the PWBs.
2
Table Stand
Table Stand (Cover)
Cabinet BCabinet A
5
4
1
Terminal Cover
6-7
6-8
6-9
6-6
6-56-4
6-3
6-2
6-1
3
3
Speaker Assembly (Left)Speaker Assembly (Right)
SC1201
SC1202
P753
P701P7305
P303
P754
P755 P2001
P7102P7101
P7301
SC3401
SC3405
SC7001
SC401
P3701
P7751
P7753
P7755
P4004
P3206
(INVERTER Unit)
(TERMINAL Unit)
(OPERATION Unit)
8
8
8
7
8
8
8
7
7
7
Tape
Speaker (Right) Connection Cable
Tape
TapeTape
Tape
Tape (MAIN Unit)
7
7
Terminal PWB Holder
Speaker (Left) Connection Cable
(Y/C SEPARATIONUnit)
7
LC-20A2M
LCD Display Unit
MAIN Unit
TERMINAL PWB Assembly
OPERATION Unit
Cabinet A
INVERTER Unit
Y/C SEPARATION Unit
14
13
12
911
10
12
13
Reinforcement Plate
9. Remove the four lock screws from the MAIN PWB.10. Remove the four lock screws from the Y/C SEPARATION PWB.11. Remove the three lock screws from the INVERTER PWB.12. Remove the lock screw from the TERMINAL PWB and the lock screw from the grounding
terminal. Detach the reinforcement plate too.13. Remove the two lock screws from the LCD display unit.14. Remove the three lock screws from the OPERATION PWB.
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LC-20A2M
» Precautions in handling the LCD panels1. Work in a clean room (with humidities below 50%).2. Be sure to wear an anti-static armband.3. Handle the panels on an electroconductive mat.4. Be careful not to fall, shake and shock the panels.
15. Remove the four lock screws from the front of the LCD display unit andthe three lock screws from its back. Detach the shielding plate.
16. Detach the two reflection sheets.17. Detach the top and bottom fluorescent lamps.18. Remove the photoconductive plate.19. Detach the top and bottom reflection sheets.20. Detach the ITO sheet.21. Detach the diffusion sheet and
ADJUSTMENT PROCEDURESThe product has been factory-adjusted to optimum settings. If by any chance any of the settings gets out of positionor when a part has been replaced, take the following procedures.
PreparationsUse the specific AC adaptor or a regulated DC power supply.AC adaptor: UADP-0219CEZZDC power supply: 13 V, 4.2 A (monitor power 3.6 A, audio amplifier power 1.0 A)
1. Adjustment Procedures1-1. Adjusting the checker
Turning on the power (getting initialized) → Selecting the model number and screen size (inches) → Transferring the model-specified data to the setting EEPROM (I2C) →Calling the adjustment process mode → +B adjustment
1-2. Making finish process adjustmentsTurning on the power → Calling the adjustment process mode (with the remote controller) →Adjusting the counter bias, TV contrast and white balance
2. Calling the Adjustment Process ModeThere are two ways to enter this mode.
» Set the KEY4 (pin (81) of IC2001) and KEY5 (pin (82) of IC2001) to the L level and turn on the power.» Hold down both the “TV/VIDEO” and “MENU” keys at once and turn on the main power. (Make sure “K”
appears at the top left of the screen, which means the set is in the inspection process mode.) Then press the“CH "” and “VOL –” keys at once. To quit this mode, just turn off the main power. (The mode can be turnedoff with the power switch either on the set or the remote controller.)
3. Key Operation in the Adjustment Process ModeSelecting a receiving channel
» Select an actual receiving channel with the “CH "/'” keys.Short push-in : Channels are selected one after another.Long push-in : Channels are skipped up to the next receivable channel.
» AdjustmentsAll the items can be adjusted one by one with the “MENU”, “CH "/'” and “VOL (+)/(–)” keys (on the set andthe remote controller).
» The “MENU” key serves to toggle between adjustment items (the next item is selected).Let’s suppose that the item at the bottom line is now selected. Press the “MENU” key and the item at the topline on the next page will be selected.
» The “TV/VIDEO” key is also used to toggle between adjustment items.Let’s suppose that the item at the top line is now selected. Press the “TV/VIDEO” key and the item at thebottom line on the previous page will be selected.
» Whichever item is selected, pressing the “AUTO PRESET” key selects the item at the top line on the next page.Page 1 → Page 2 → ... → Page 16 → Page 1 ...
» Whichever item is selected, pressing the “MANUAL MEMORY” key selects the item at the top line on thesame page. Using the “VOL (+)/(–)” keys, the setting of a selected item can be modified.
» Let’s suppose that the PAL/NTSC is selected on pages 11 and 12. By pressing the “VOL (+)/(–)” keys, theregister selection mode is brought on and the cursor moves to the address 01.
» Using the “CH "/'” and “VOL (+)/(–)” keys, move the cursor vertically and horizontally, respectively. Use the“12” key to enter the setting.With an item selected, the cursor moves to its setting. Using the “VOL (+)/(–)” keys, the setting of the itemselected can be changed first for the left side. A new setting is now entered with the “12” key. Using the “VOL(+)/(–)” keys again, the right-side setting can also be changed.0 ←→ 1 ←→ ...←→ 9 ←→ A ←→ ... ←→ F ←→ 0 ←→ ...Enter the setting with the “12” key. Go back to the address selection and go to the next item with the “MENU”key. The cursor moves for address selection as follows using the “VOL (+)/(–)” keys.Example : 01←→ 02 ←→ 03 ←→ 01 ←→ ...Similarly the cursor moves as follows with the “CH "/'” keys.Example : 02 ←→ 05 ←→ ... ←→ F6 ←→ 02 ←→ ...
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LC-20A2M
4. Getting Initialized4-1. Connect pins (81) and (82) of IC2001 to GND. Turn on the power.4-2. Select the model number (A2H).4-3. Select the screen size (20 inches).
5. Adjustments5-1. +B adjustment (+B ADJ. on page 1)
1) Receive the colour bar signal.2) Adjust the voltage at pin (8) of P303 to 5.00 ±0.02 V.Note: The 5.00 V level is used as reference to the supply voltage. Make an exact adjustment to 5.00 V.
5-2. Counter bias adjustment ...... “COM BIAS” on page 21) Receive the monoscope pattern signal.2) Adjust the “COM BIAS” setting so that the contrast at the staircase wave is maximum.
5-3. TAMP adjustment1) Receive the colour bar signal.2) See if the “Y” reading on page 2 of the adjustment process is somewhere between BB and CA. If not,
make the “NTSC TAMP” adjustment to get the “Y” reading in the range of BB thru CA.3) Then enter the above setting, if made in the “NTSC TAMP” adjustment, in the following items in the
manual mode.“PAL TAMP”, “SECAM TAMP”, “PAL-M TAMP” and “PAL-N TAMP”.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
0 1
2
2
C
N
P
S
P
P
T
R
G
B
G
G
3
O
T
A
E
A
A
V
C
C
C
3
1
4
M
S
L
C
L
L
U
U
U
5
C
A
-
-
H
T
T
T
6
B
T
M
M
N
-
O
O
O
B
B
7
I
T
A
P
F
F
F
3
4
8
A
A
M
T
T
T
E
F
F
F
9
S
M
P
A
A
A
A
10
P
M
M
M
K
R
11
P
P
P
I
3
Y
12
N
13
G
14 15 16
0
0
17
0
0
18 19 20
0
0
21
0
0
22 23
1
24
1
1
2
2
2
2
0
B
25
7
9
7
7
7
7
4
0
0
0
0
5
26
(Adjustment process menu on-screen display on page 2)
Y data (75% white)
5-4. White balance adjustment1) Receive the monoscope pattern signal.2) Adjust so that the “RCUTOFF” and “BCUTOFF” settings on page 2 of the adjustment process are optimum.
Note: The “RCUTOFF” and “BCUTOFF” settings in the adjustment process should be in the range of -10 thru+10. If without this range, the variable user control range will be reduced.
1514
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
CHASSIS LAYOUT
MAIN Unit (Side A) Y/C SEPARATION Unit (Side A)
MAIN Unit (Side B) Y/C SEPARATION Unit (Side B)
OP
ER
AT
ION
Un
it
INV
ER
TE
R U
nit
TE
RM
INA
L U
nit
1716
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
BLOCK DIAGRAM
18
LC-20A2M
DESCRIPTION OF SCHEMATICDIAGRAM
VOLTAGE MEASUREMENT CONDITION:1. When the exclusive-use AC adapter is used, the colour
bar signal of colour bar generator for service is input toget the normal screen. When the audio is minimized,the voltage value is measured with the 20 kΩ/V tester.
WAVEFORM MEASUREMENT CONDITION:1. When the exclusive-use AC adapter is used, the colour
density, lightness and colour hue are set to the centerposition, and the signal of colour bar generator forservice is observed to get waveform.
INDICATION OF RESISTOR & CAPACITOR:
RESISTOR1. The unit of resistance “Ω” is omitted.
(K=kΩ=1000 Ω, M=MΩ).2. All resistors are ± 5%, unless otherwise noted.
(J= ± 5%, F= ± 1%, D= ± 0.5%)3. All resistors are Carbon type, unless otherwise noted.
C : Solid W : CementS : Oxide Film T : SpecialN : Metal Coating
CAPACITOR1. All capacitors are mF, unless otherwise noted.
(P=pF=mmF).2. All capacitors are Ceramic type, unless otherwise
CAUTION:This circuit diagram is original one, therefore there may be aslight difference from yours.
IMPORTANT SAFETY NOTICE:PARTS MARKED WITH “å” ( )AREIMPORTANT FOR MAINTAINING THE SAFETY OFTHE SET. BE SURE TO REPLACE THESE PARTSWITH SPECIFIED ONES FOR MAINTAINING THESAFETY AND PERFORMANCE OF THE SET.
19
654321
A
B
C
D
E
F
G
H
LC-20A2M
Ë OPERATION Unit
2120
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
Ë MAIN Unit -1/2
2322
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
Ë MAIN Unit -2/2
2524
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
Ë TERMINAL Unit
2726
LC-20A2M
121110987654321
A
B
C
D
E
F
G
H
Ë Y/C SEPARATION Unit
28
654321
A
B
C
D
E
F
G
H
LC-20A2M
Ë INVERTER Unit
Ref. No. Part No. Description Code Ref. No. Part No. Description Code
34
LC-20A2M
PARTS LISTPARTS REPLACEMENT
Replacement parts which have these special safety characteristicsidentified in this manual: electrical components having such featuresare identified by "å" in the Replacement Parts Lists.The use of a substitute replacement part which does not have thesame safety characteristics as the factory recommended replace-ment parts shown in this service manual may create shock, fire orother hazards.
"HOW TO ORDER REPLACEMENT PARTS"To have your order filled promptly and correctly, please furnish thefollowing informations.
DUNTKA177FE05 – MAIN Unit —DUNTKA194DE05 – Y/C SEPARATION Unit —DUNTKA331DE01 – TERMINAL Unit —DUNTKA332DE01 – INVERTER Unit —DUNTKA333DE01 – OPERATION Unit —
PSLDM4647CEFW J Shield ADQEARZ0043CEZZ J Electrostatic Earth AC
CABINET PARTS LOCATION
1 CCABA2380CE07 J Front Cabinet Ass’y BX1-1 Not Available – Cabinet —1-2 GCOVA1808CEZZ J Cover, LED AE1-3 GCOVA1798CESA J Cover, Front (L) AF1-4 GCOVA1917CEKA J Cover, Front (R) AG1-5 GCOVA1932CESA J Cover, IR Filter AC1-6 GDORF2048CEKA J Front Door AF1-7 HDECA0759CESA J Decoration Panel BW1-8 HiNDP5645CESA J Indication Plate AD
(Cabinet Side)1-9 HiNDP5666CESA J Indication Plate AD
(Door Side)1-10 JBTN-2057CEKA J Power Button AF1-11 LX-HZ3111CEFN J Screw, x4 AB1-12 MSPRC0203CEFW J Spring for Power Button AC1-13 MSPRP0204CEFW J Spring, for Door AD1-14 PMLT-0356CEZZ J Light Shielding Plate AB1-15 PSHEP0027CEZZ J Sheet AA1-16 PSPAH0623CEZZ J Spacer, x7 AB1-17 PSPAH0624CEZZ J Spacer, x2 AB1-18 PSPAZ0315CEZZ J Spacer AD1-19 PSPAZ0316CEZZ J Spacer, x2 AD1-20 QEARZ0026CEZZ J Grounding Part AC1-21 XEBSD30P08000 J Screw AA