SHARP LC-20A2M Service Manual

TENTATIVE
SERVICE MANUAL
S00K2LC-20A2H
LCD COLOUR TELEVISION
LC-20A2M
MODEL
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.
LC-20A2M
CONTENTS
Page Page
»
IMPORTANT SERVICE SAFETY PRECAUTION......
» 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
2
» 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
The component parts of this model are par tially different depending on their suffix symbols. Bef ore servicing the units, be sure to check the suffix symbol on the model label that is applied on the back of the unit.
Example of suffix symbol:
LCD COLOUR TV MODEL LC-20A2M 13V 3.7A, 48W
SERIAL NO.
SHARP CORPORATION MADE IN JAPAN
SHARP CORPORATION
X xxxxxxxxx
N1
Suffix "X" for Australlia
1
LC-20A2M
2
2
IMPORTANT SERVICE SAFETY PRECAUTION
Ë
Service work should be perfomed only b y qualified service technicians who are thoroughl y familiar with all safety checks and the servicing guidelines which follow:
WARNING
1. For continued safety, no modification of any circuit should be attempted.
2. Disconnect AC power before servicing.
CAUTION: FOR CONTINUED PROTECTION AGAINST A RISK OF FIRE REPLACE ONLY WITH SAME TYPE FUSE. F3701 (2.0A, 250V), F3702 (2.5A, 250V), F7751 (5.0A, 250V) FUSE.
BEFORE RETURNING THE RECEIVER (Fire & Shock Hazard)
Before returning the receiver to the user, perform the following safety checks:
1. Inspect all lead dress to make certain that leads are not pinched, and check that hardware is not lodged between the chassis and other metal parts in the receiver.
2. Inspect all protective devices such as non-metallic control knobs, insulation materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor networks, mechanical insulators and etc.
3. To be sure that no shock hazard exists, check for leakage current in the following manner.
Plug the AC cord directly into a 110~240 volt A C outlet, and connect the DC power cable into the receiver's DC jack. (Do not use an isolation transformer for this test).
Using two clip leads, connect a 50k ohm, 10 watt resistor paralleled by a 0.15µF capacitor in series with all exposed metal cabinet parts and a known earth ground, such as electrical conduit or electrical ground connected to an earth ground.
Use an AC voltmeter ha ving with 5000 ohm per volt, or higher, sensitivity or measure the AC voltage drop across the resisor.
Connect the resistor connection to all exposed metal parts having a return to the chassis (antenna, metal cabinet, screw heads, knobs and control shafts, escutcheon and etc.) and measure the AC voltage drop across the resistor. All checks must be repeated with the AC cord plug connection reversed. (If necessary, a nonpolarized adaptor plug must be used only for the purpose of completing these checks.) Any reading of 35V peak (this corresponds to 0.7 milliamp. peak A C .) or more is e xcessive and indicates a potential shock hazard which must be corrected before returning the monitor to the owner .
DVM
AC SCALE
50k ohms.
10W
0.15 µF
TEST PROBE
TO EXPOSED METAL PARTS
CONNECT TO KNOWN EARTH GROUND
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
SAFETY NOTICE
Many electrical and mechanical parts in LCD television have special safety-related characteristics. These characteristics are often not evident from visual inspection, nor can protection afforded by them be necessarily increased by using replacement components rated for higher voltage, wattage and etc. Replacement parts which have these special safety characteristics are identified in this manual; electrical
and shaded areas in the
Schematic Diagrams
For continued protection, replacement parts must be identical to those used in the original circuit. The use of a substitute replacement parts which do not have the same safety characteristics as the factory recommended replacement parts shown in this service manual, may create shock, fire or other hazards.
components having such features are identified by “ å”
234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121
2
Replacement Parts Lists
.
and
Specifications
LC-20A2M
3
LC-20A2M
Operation Manual
Main unit (front view)
Main unit (rear view)
Remote control
4
Dimensions
LC-20A2M
(Unit: mm)
5
LC-20A2M
REMOVING OF MAJOR PARTS
1. Detach the terminal cover.
2. Remove the four lock screws from the table stand.
3. Remove the four lock scre ws 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 6-9
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.
6-1
first and then the hooks
6-2
thru
3
Speaker (Right) Connection Cable
Terminal PWB Holder
Speaker Assembly (Right)
Cabinet B Cabinet A
SC1201
(MAIN Unit)
Tape
7
Tape
Tape
8
SC1202
P755
P754
8
P753
7
7
Tape
P701
P2001
P303
6-7
8
3
6-6
6-8
6-9
SC401
SC3401
SC3405
6-4
6-5
SC7001
(Y/C SEPARATION Unit)
P7102
P7101
P7301
P7305
(TERMINAL Unit)
P3701
5
4
6-3
P7753
(INVERTER Unit)
8
P7755
P7751
P3206
Speaker Assembly (Left)
Terminal Cover
6-2
1
6-1
2
Table Stand (Cover)
Table Stand
8
7
Speaker (Left)
8
Connection Cable
Tape
7
(OPERATION Unit)
P4004
6
Tape
7
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.
Y/C SEPARATION Unit
9
10
11
INVERTER Unit
TERMINAL PWB Assembly
MAIN Unit
LC-20A2M
12
LCD Display Unit
13
12
14
OPERATION Unit
13
Reinforcement Plate
Cabinet A
7
LC-20A2M
» Precautions in handling the LCD panels
1. 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 and the 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 reflection/deflection plate.
15
LCD Display Unit (Front)
Lamp Reflector (PSHEP0223CEZZ)
Photoconductive Plate
ITO Sheet
20
Fluorescent Lamp (Top) (KLMP-0101CEZZ)
17
19
18
15
16
Reflection Sheet (PSHEP0187CEZZ)
Reflection Sheet
17
(PSHEP0186CEZZ)
Fluorescent Lamp (Bottom) (KLMP-0102CEZZ)
15
15
Shielding Plate
LCD Display Unit
21
Diffusion Sheet
Reflection/deflection Plate
8
Lamp Reflector (Bottom)
19
(PSHEP0224CEZZ)
No picture
at all
Yes
No
Are inputs
and outputs
of IC802 as
specified?
Check all the settings on the microprocessor’s adjust process menu.
No picture
Check IC802
and its
peripheral
parts.
Yes
No
Are inputs
and outputs
of IC1201 as
specified?
Check
IC1201 and
its peripheral
parts.
Check LCD
panel voltage
and
waveform.
No TV and
VIDEO 1
output
Yes
No
Are inputs
and outputs
of IC402 as
specified?
Check IC402
and its
peripheral
parts.
No
Is input at pin
(73) of IC802
as specified?
Check IC802,
AV1 line and
their
peripheral
parts.
No TV
output
Yes
No
Are voltages
at pins (6),
(7) and (9) of
tuner as
specified?
Check the
power line.
Yes
No
Is output at
pin (19) of
tuner as
specified?
Check the
tuner and its
peripheral
parts.
No
Is input at pin
(1) of IC402
as specified?
Check the
line in
question.
Yes
Check IC402
and its
peripheral
parts.
Yes
No
Are pins (2)
and (4) of
IC402 at “H”
and “L”
respectively?
Are pins (65)
and (66) of
IC2001 at “H”
and “L”
respectively?
No VIDEO
1 output
Yes
No
Is input at pin
(1) of IC402
as specified?
Check the
line in
question.
Yes
No
Are pins (2)
and (4) of
IC402 both at
“L”?
No VIDEO
2 output
No
Is input at pin
(74) of IC802
as specified?
Check J3403,
AV2 line and
their
peripheral
parts.
No S
VIDEO
output
No
Are inputs at
pins (71) and
(72) of IC802
as specified?
Check
SC3301, SY
line, SC line
and
peripheral
parts.
No
COMPONENT
output
No
Is input at
pins (4), (5),
(6) and (75)
of IC802 as
specified?
Check J3405,
DVD-Y line,
CB line, CR
line and
peripheral
parts.
Are pins (65)
and (66) of
IC2001 both
at “L”?
Check IC402
and its
peripheral
parts.
Yes
Check the
line in
question.
Yes
Check the
line in
question.
TROUBLE SHOOTING TABLE
LC-20A2M
9
LC-20A2M
No picture and sound
No colour
No TV colour
No S-VIDEO colour
Yes
No
Do F3701 and F3702
function?
Check all the settings on the microprocessor
s adjust process menu.
No
Are secondary outputs
(+38V, +16V, +9V, +5V, -8V)
of T701 as specified?
Yes
Are the oscillation waveform
at T701’s primary side as
specified?
Yes
No
Disconnect F3701 and
F3702. Is the load side
short-circuited?
Yes
No
Is any of T701’s primary side,
Q701, Q710 and S4701
short-circuited?
Check J3701, its peripheral
parts and connection cable.
Replace F3701 and F3702.
Check S4701 and
connection cable.
Check the secondary-side
load of T701.
Fluorescent lamp
Yes
No
Does F7751 function?
Yes
No
Is Pin (34) of IC1201 at
H?
Yes
No
Are the oscillation waveforms
at the primary side of T7751-6
as specified?
Yes
Replace F7751.
No
Is input at pin (71) of IC802
as specified?
Check SC3301, SC line and
peripheral parts.
Yes
Check the line, IC1201 and
its peripheral parts.
Check Q7751-5, T7751-6
and their peripheral parts.
Replace the fluorescent lamp
and check the oscillation
waveform again.
No VIDEO colour
Check all the settings on the microprocessor
s adjust process menu.
No COMPONENT colour
No
Is input at pins (4) and (6) of
IC802 as specified?
Check J3405, CB line, CR
line and peripheral parts.
TROUBLE SHOOTING TABLE (Continued)
10
No sound
from
speakers
Yes
No
Is pin (53) of
IC2001 at “L”?
Check all the settings on the microprocessor
s adjust process menu.
No sound
No
Are outputs at
pins (1) and (7)
of IC903 as
specified?
Yes
No
Are inputs and
outputs of
IC303 as
specified?
Yes
No
Are inputs at
pins (11) and
(16) as well as
outputs at pins
(3) and (5), all
of IC7305, as
specified?
Muting effect is
on. Check the
FSMU line.
Check IC901,
IC903 and their
peripheral
parts.
Check IC303
and its
peripheral
parts.
Check the line
in question,
IC7305 and its
peripheral
parts.
Yes
Check the
speakers and
their peripheral
parts.
No sound
from
headphone
Yes
No
Is pin (55) of
IC2001 at L”?
Check the
headphone and
its peripheral
parts.
Check Q306,
J4001 and their
peripheral
parts.
No sound
from output
line
Yes
No
Is pin (52) of
IC2001 at L”?
No
Are outputs at
pins (1) and (7)
of IC902 as
specified?
Yes
Check the line
in question.
Check the
LMUTE line.
Check IC902
and its
peripheral
parts.
TV sound
failure
Yes
No
Is output at pin
(16) of tuner as
specified?
No
Is input at pin
(60) of IC901
as specified?
Check the
tuner and its
peripheral
parts.
Check IC901,
Q3301, Q3204,
Q3205 and
their peripheral
parts.
TROUBLE SHOOTING TABLE (Continued)
LC-20A2M
11
LC-20A2M
ADJUSTMENT PROCEDURES
The product has been factory-adjusted to optimum settings. If by any chance any of the settings gets out of position or when a part has been replaced, take the following procedures.
Preparations
Use the specific AC adaptor or a regulated DC power supply. AC adaptor: UADP-0219CEZZ DC power supply: 13 V, 4.2 A (monitor power 3.6 A, audio amplifier power 1.0 A)
1. Adjustment Procedures
1-1. 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 adjustments
Turning 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 Mode
There 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 turned off with the power switch either on the set or the remote controller.)
3. Key Operation in the Adjustment Process Mode
Selecting 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.
» Adjustments
All the items can be adjusted one by one with the “MENU”, “CH "/'” and “VOL (+)/(–)” keys (on the set and the 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 top line 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 the bottom line on the previous page will be selected.
» Whichever item is selected, pressing the “AUT O 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 the
same 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, the
register selection mode is brought on and the cursor moves to the address 01.
» Using the “CH "/'” and “VOL (+)/(–)” keys, move the cursor v ertically 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 item selected 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 ←→ ...
12
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