JVC LT-20DA6SK User manual

SERVICE MANUAL
COPYRIGHT © 2005 Victor Company of Japan, Limited No.YA354
2005/11
WIDE LCD PANEL TELEVISION
YA354200511
LT-20DA6SK
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
P
BACK
TOP MENU
ZOOM
PC
TV
RM-C1896
1
456
9
8
7
0
23
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MENUTV/DTV
AV
DVDVCR TV
OK

1-2 (No.YA354)
SPECIFICATION
Design & specifications are subject to change without notice.
Items Contents
Dimensions ( W ×H ×D ) 53.7cm ×41.1cm ×21.4cm [Included stand]
53.7cm ×37.7cm ×9.7cm [TV only]
Mass 6.5kg [Included stand]
5.5kg [TV only]
Power Input ADAPTOR
TV
AC100 ~ 240V 50Hz
DC24V
Power Consumption 80W (Standby: 3.0W)
TV RF System Analog
Digital
CCIR (I)
DVB-T
Colour System PAL / NTSC 3.58/4.43 [EXT only]
Stereo System NICAM (I)
Receiving Frequency Analog
Digital
UHF: 470 MHz - 862 MHz
UHF: 474 MHz - 850 MHz
Intermediate
Frequency
VIF
SIF
38.9 MHz (I)
32.9 MHz (6.0 MHz :I)
Colour Sub
Carrier Frequency
PAL
NTSC
4.43 MHz
3.58 MHz / 4.43 MHz
Teletext System Analog
Digital
FLOF (Fastext level 2.5), WST(World Standard system)
MHEG 5 UK profile
LCD panel 20V-inch wide aspect (15:9)
Screen Size Diagonal : 50.9cm (H: 44.3cm ×V : 24.9cm)
Display Pixels Horizontal : 1366 dots ×Vertical : 768 dots (W-XGA)
Audio Power Output 5W + 5W(10% THD)
Speaker 3cm ×10cm (×2)
Aerial terminal (VHF/UHF) F-type connector, 75Ωunbalanced, coaxial
EXT-1 / EXT-2 (Input / Output) 21-pin Euro connector (SCART socket ) ×2
EXT-3 (Input) Component
Audio
Y:1V(p-p) Positive (Negative sync provided), 75ΩRCA pin jack ×1
Pb / Pr : 0.7V(p-p), 75ΩRCA pin jack ×2
500mV (rms), Low impedance, RCA pin jack ×2
EXT-4 (Input) S-Video
Video
Audio
Mini-DIN 4 pin ×1
Y: 1V (p-p), Positive (Negative sync provided), 75 Ω
C: 0.286V (p-p) (Burst signal), 75 Ω
1V (p-p), Positive (Negative sync provided), 75 Ω, RCA pin jack ×1
500mV (rms), High impedance, RCA pin jack ×2
PC (RGB) Input D-sub 15pin ×1
R/G/B : 0.7V (p-p), 75Ω
HD / VD : 1V (p-p) to 5V (p-p), high impedance
< Available signal >
VGA : 640 pixels ×480 pixels (Horizontal : 31.5kHz / Vertical : 60Hz)
XGA : 1024 pixels ×768 pixels (Horizontal : 48.4kHz / Vertical : 60Hz)
PC AUDIO input 3.5mm stereo mini jack ×1
Audio output 500mV (rms), Low impedance, RCA pin jack ×2
Sub Woofer out 500mV (rms), Low impedance, RCA pin jack ×1
Headphone 3.5mm stereo mini jack ×1
Remote Control Unit RM-C1895 (AA/R6 dry cell battery ×2)

(No.YA354)1-3
SECTION 1
PRECAUTION
1.1 SAFETY PRECAUTIONS
(1) The design of this product contains special hardware and many circuits and components specially for safety purposes. For
continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer.
Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel
only.
(2) Alterations of the design or circuitry of the product should not be made. Any design alterations or additions will void the
manufacturer's warranty and will further relieve the manufacturer of responsibility for personal injury or property damage
resulting therefrom.
(3) Many electrical and mechanical parts in the product have special safety-related characteristics. These characteristics are often
not evident from visual inspection nor can the protection afforded by them necessary be obtained by using replacement
components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are
identified in the Parts List of Service Manual. Electrical components having such features are identified by shading on the
schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the
same safety characteristics as the recommended replacement part shown in the Parts List of Service Manual may cause shock,
fire, or other hazards.
(4) The leads in the products are routed and dressed with ties, clamps, tubing’s, barriers and the like to be separated from live parts,
high temperature parts, moving parts and / or sharp edges for the prevention of electric shock and fire hazard. When service is
required, the original lead routing and dress should be observed, and it should be confirmed that they have been returned to
normal, after re-assembling.
WARNING
(1) The equipment has been designed and manufactured to meet international safety standards.
(2) It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
(3) Repairs must be made in accordance with the relevant safety standards.
(4) It is essential that safety critical components are replaced by approved parts.
(5) If mains voltage selector is provided, check setting for local voltage.

1-4 (No.YA354)
1.2 INSTALLATION
1.2.1 HEAT DISSIPATION
If the heat dissipation vent behind this unit is blocked, cooling
efficiency may deteriorate and temperature inside the unit will
rise. The temperature sensor that protects the unit will be
activated when internal temperature exceeds the pre-determined
level and power will be turned off automatically.Therefore,
please make sure pay attention not to block the heat dissipation
vent as well as the ventilation outlet behind the unit and ensure
that there is room for ventilation around it.
1.2.2 INSTALLATION REQUIREMENTS
Ensure that the minimal distance is maintained, as specified
below, between the unit with and the surrounding walls, as well
as the floor etc.Install the unit on stable flooring or stands.Take
precautionary measures to prevent the unit from tipping in order
to protect against accidents and earthquakes.
1.2.3 NOTES ON HANDLING
(1) WHEN TAKING UNIT OUT OF A PACKING CASE
When taking the unit out of a packing case, do not grasp
the upper part of the unit. If you take the unit out while
grasping the upper part, the LCD PANEL may be damaged
because of a pressure. Instead of grasping the upper part,
put your hands on the lower backside or sides of the unit.
(2) AS FOR PRESSING OR TOUCHING A SPEAKER
Be careful not to press the opening of the speaker in the
lower part of the unit and around them since the decorative
sheet on the surface of the openings may be deformed.
Ventilation
hole
*Diagram differs from actual appearance.
100 mm
100 mm
100 mm
100 mm
50 mm

(No.YA354)1-5
1.3 HANDLING LCD PANEL
1.3.1 PRECAUTIONS FOR TRANSPORTATION
When transporting the unit, pressure exerted on the internal LCD
panel due to improper handling (such as tossing and dropping)
may cause damages even when the unit is carefully packed. To
prevent accidents from occurring during transportation, pay
careful attention before delivery, such as through explaining the
handling instructions to transporters.
Ensure that the following requirements are met during
transportation, as the LCD panel of this unit is made of glass and
therefore fragile:
(1) USE A SPECIAL PACKING CASE FOR THE LCD PANEL
When transporting the LCD panel of the unit, use a special
packing case (packing materials). A special packing case
is used when a LCD panel is supplied as a service spare
part.
(2) ATTACH PROTECTION SHEET TO THE FRONT
Since the front (display part) of the panel is vulnerable,
attach the protection sheet to the front of the LCD panel
before transportation. Protection sheet is used when a LCD
panel is supplied as a service spare part.
(3) AVOID VIBRATIONS AND IMPACTS
The unit may be broken if it is toppled sideways even when
properly packed. Continuous vibration may shift the gap of
the panel, and the unit may not be able to display images
properly. Ensure that the unit is carried by at least 2
persons and pay careful attention not to exert any vibration
or impact on it.
(4) DO NOT PLACE EQUIPMENT HORIZONTALLY
Ensure that it is placed upright and not horizontally during
transportation and storage as the LCD panel is very
vulnerable to lateral impacts and may break. During
transportation, ensure that the unit is loaded along the
traveling direction of the vehicle, and avoid stacking them
on one another. For storage, ensure that they are stacked
in 2 layers or less even when placed upright.
1.3.2 OPTICAL FILTER (ON THE FRONT OF THE LCD PANEL)
(1) Avoid placing the unit under direct sunlight over a
prolonged period of time. This may cause the optical filter
to deteriorate in quality and COLOUR.
(2) Clean the filter surface by wiping it softly and lightly with a
soft and lightly fuzz cloth (such as outing flannel).
(3) Do not use solvents such as benzene or thinner to wipe the
filter surface. This may cause the filter to deteriorate in
quality or the coating on the surface to come off. When
cleaning the filter, usually use the neutral detergent diluted
with water. When cleaning the dirty filter, use water-diluted
ethanol.
(4) Since the filter surface is fragile, do not scratch or hit it with
hard materials. Be careful enough not to touch the front
surface, especially when taking the unit out of the packing
case or during transportation.
1.3.3 PRECAUTIONS FOR REPLACEMENT OF EXTERIOR
PARTS
Take note of the following when replacing exterior parts (REAR
COVER, FRONT PANEL, etc.):
(1) Do not exert pressure on the front of the LCD panel (filter
surface). It may cause irregular COLOUR.
(2) Pay careful attention not to scratch or stain the front of the
LCD panel (filter surface) with hands.
(3) When replacing exterior parts, the front (LCD panel) should
be placed facing downward. Place a mat, etc. underneath
to avoid causing scratches to the front (filter surface).

1-6 (No.YA354)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 FEATURES
T-V LINK
When you have a T-V LINK compatible VCR connected to the
EXT-2 Terminal on the TV,it is easier to set up the VCR and to
view videos.
ZOOM
This function can change the screen size according to the
picture aspect ratio.
OFF TIMER
This function can set the TV to automatically turn off after a set
time.
COLOUR SYSTEM
If the picture is not clear or no colour appears, change the
current colour system to another colour system.
2.2 21-PIN EURO CONNECTOR (SCART) : EXT-1 / EXT-2
(P-P= Peak to Peak, B-W= Blanking to white peak)
Pin No. Signal designation Matching value EXT-1 EXT-2
1 AUDIO R output 500mV(rms) (Nominal),, Low impedance Used (TV OUT) Used (LINE OUT)
2 AUDIO R input 500mV(rms) (Nominal),, High impedance Used (R1) Used (R2)
3 AUDIO L output 500mV(rms) (Nominal),, Low impedance Used (TV OUT) Used (LINE OUT)
4 AUDIO GND Used Used
5 GND (B) Used Used
6 AUDIO L input 500mV(rms) (Nominal),, High impedance Used (L1) Used (L2)
7 B input 700mV(B-W), 75ΩUsed Used
8 FUNCTION SW
(SLOW SW)
Low : 0V-3V
High : 8V-12V, High impedance
Used Used
9 GND (G) Used Used
10 SCL / T-V LINK Not used Used
(SCL2 / TV-LINK)
11 G input 700mV(B-W), 75ΩUsed Used
12 SDA Not used Used (SDA2)
13 GND (R) Used Used
14 GND (YS) Used Not used
15 R / C input R : 700mV(B-W), 75Ω
C : 300mV(P-P), 75ΩUsed (R) Used (C2/R)
16 Ys input (FAST SW) Low : 0V-0.4V, High : 1V-3V, 75ΩUsed Used
17 GND (VIDEO output) Used Used
18 GND (VIDEO input) Used Used
19 VIDEO output 1V(P-P) (Negative sync), 75ΩUsed (TV OUT) Used (LINE OUT)
20 VIDEO / Y input 1V(P-P) (Negative sync), 75ΩUsed Used
21 COMMON GND Used Used
20 18 16 14 12 10 8 6 4 2
21 19 17 15 13 11 9 7 5 3 1
[Pin assignment]

(No.YA354)1-7
2.3 TECHNICAL INFORMATION
2.3.1 LCD PANEL
This unit uses the flat type panel LCD (Liquid Crystal Display) panel that occupies as little space as possible, instead of the
conventional CRT (Cathode Ray Tube), as a display unit.
Since the unit has the two polarizing filter that are at right angles to each other, the unit adopts "normally black" mode, where light
does not pass through the polarizing filter and the screen is black when no voltage is applied to the liquid crystals.
2.3.1.1 SPECIFICATIONS
The following table shows the specifications of this unit.
2.3.1.2 PIXEL FAULT
There are three pixel faults - bright fault , dark fault and flicker fault - that are respectively defined as follows.
BRIGHT FAULT
In this pixel fault, a cell that should not light originally is lighting on and off.
For checking this pixel fault, input ALL BLACK SCREEN and find out the cell that is lighting on and off.
DARK FAULT
In this pixel fault, a cell that should light originally is not lighting or lighting with the brightness twice as brighter as originally lighting.
For checking this pixel fault, input 100% of each R/G/B colour and find out the cell that is not lighting.
FLICKER FAULT
In the pixel fault, a cell that should light originally or not light originally is flashing on and off.
For checking this pixel fault, input ALL BLACK SCREEN signal or 100% of each RGB colour and find out the cell that is flashing on
and off.
Item Specifications Remarks
Displayed colour 16777216 colours 256 colours for R, G, and B
Brightness 450cd/m2
Contrast ratio 400: 1
Response time 25ms
View angle Horizontally: 176°, Vertically: 176°

1-8 (No.YA354)
2.4 BASIC OPERATION OF SERVICE MODE
2.4.1 HOW TO ENTER THE SERVICE MODE
(1) Press [INFORMATION] key and [MUTING] key on the
remote control unit simultaneously to enter the SERVICE
MODE SCREEN.
2.4.2 HOW TO EXIT THE SERVICE MODE
Press the [MENU] key to exit the Service mode.
2.4.3 CHANGE AND MEMORY OF SETTING VALUE
SELECTION OF SETTING MENU & ITEM
•[FUNCTION /]key : Select the SETTING MENU & ITEM
•[OK] key : Decision the SETTING MENU & ITEM
CHANGE OF SETTING VALUE (DATA)
• [FUNCTION /] key.
MEMORY OF SETTING VALUE (DATA)
The setting value will be stored automatically when release the
REMOTE CONTROL UNIT keys
2.4.4 SERVICE MODE SELECT KEY LOCATION
2.4.5 SERVICE MODE SETTING ITEMS
Service
Adjust ...
Options...
Aps Wss Test ...
JVC20w IDTV 0. 0. 236
AUG 23 2005 16:28:58
SERVICE MODE SCREEN
P
BACK
TOP MENU
ZOOM
PC
TV
RM-C1896
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MENUTV/DTV
AV
DVDVCR TV
OK
[MUTING]
[FUNCTION ޓ/ ]
[FUNCTIONޓ/ ]
[INFORMAITION]
[OK]
[BACK]
[MENU]
Setting
menu Setting items Contents
Adjust Group ----
Mode ----
Col. Temp. ----
Contrast ----
Brightness ----
Colour ----
Sharpness ----
Red ----
Green ----
Blue ----
Aps Volume ----
Option 1 First APS If ON, TV starts with APS
menu at Start-up
FM Prs Avl On Adjusts the FM Prescaler
value, when Automatic
Volume Levelling is On
Nicam Prs Avl On Adjusts the Nicam Prescal-
er value, when Automatic
Volume Levelling is On
Scart Prs Avl On Adjusts the Scart Volume
value, when Automatic
Volume Levelling is On
Scart Volume Avl On Adjusts the Scart Volume
value, when Automatic
Volume Levelling is On
FM Prs Avl Off Adjusts the FM Prescaler
value, when Automatic
Volume Levelling is Off
Nicam Prs Avl Off Adjusts the Nicam Prescal-
er value, when Automatic
Volume Levelling is Off
Scart Prs Avl Off Adjusts the Scart Prescal-
er value, when Automatic
Volume Levelling is Off
Scart Volume Avl Off Adjusts the Scart Volume
value, when Automatic
Volume Levelling is On
Avl Enable/disable Automatic
Volume Levelling System
Sound ----
Option 2 Carrier ----
LDLY ----
AGC ----
Other MAD ----
Aps Wss Test Programme ----
VPS ----
Pdc Format 1 ----
Pdc Format 2 ----
Name ----
WSS ----

(No.YA354)1-9
SECTION 3
DISASSEMBLY
3.1 DISASSEMBLY PROCEDURE
NOTE:
• Make sure that the power cord is disconnected from the outlet.
• Pay special attention not to break or damage the parts.
• When removing each board, remove the connectors as required.
• Taking notes of the connecting points (connector numbers) makes service procedure manageable.
• Make sure that there is no bent or stain on the connectors before inserting, and firmly insert the connectors.
3.1.1 REMOVING THE HINGE COVER
(1) Remove the 2 screws [A].
(2) Remove the HINGE COVER.
3.1.2 REMOVING THE FOOT TOP COVER
• Remove the HINGE COVER.
(1) Remove the 2 screws [B].
(2) Pull out the FOOT TOP COVER.
3.1.3 REMOVING THE FOOT ASSEMBLY
(1) Remove the 4 screws [C].
(2) Remove the FOOT ASSEMBLY.
3.1.4 REMOVING THE THE HANDLE
• Remove the HINGE COVER.
• Remove the FOOT TOP COVER.
(1) Remove the 4 screws [D].
(2) Remove the THE HANDLE.
3.1.5 REMOVING THE BACK COVER
• Remove the FOOT ASSEMBLY.
(1) Remove the 5 screws [E].
(2) Remove the BACK COVER toward you.
NOTE:
If necessary, remove the HANDLE, SIDE AV COVER, CARD
SLOT COVER and BACK DOOR.
3.1.6 REMOVING THE SIDE CONTROL PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [F].
(2) Remove the BUTTON FUNCTION with SIDE CONTROL
PWB.
(3) Remove the 4 craws which is fixing the SIDE CONTROL
PWB.
(4) Remove the SIDE CONTROL PWB
3.1.7 REMOVING THE METAL HANG
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 1 screw [G].
(2) Remove the METAL HANG.
(3) Remove the opposite METAL HANG same steps.
3.1.8 REMOVING THE TERMINAL BOARD
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [H].
(2) Remove the TERMINAL BOARD.
3.1.9 REMOVING THE MAIN PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
• Remove the TERMINAL BRACKET.
(1) Remove the 7 screws [J].
(2) Remove the MAIN PWB.
3.1.10 REMOVING THE AV JACK BRACKET
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [K].
(2) Remove the AV JACK BRACKET.
3.1.11 REMOVING THE AV JACK PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
• Remove the AV JACK BRACKET.
(1) Remove the 2 screws [L].
(2) Remove the AV JACK PWB.
3.1.12 REMOVING THE LED PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [M].
(2) Remove the LED PWB.
3.1.13 REMOVING THE SPEAKER
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the speaker wire from speaker terminal.
(2) Remove the 2 screws [N].
(3) Remove the SPEAKER PWB.
(4) Remove the opposite speaker same steps.
3.1.14 REMOVING THE LCD PANEL UNIT
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
• Remove the MAIN PWB and AV JACK PWB.
(1) Remove the 4 screws [O].
(2) Remove the 5 screw [P] fixing the DISPLAY SUPPORT
and LCD PANEL UNIT.
(3) Sightly raise the both sides of the LCD PANEL UNIT by
hand from the FRONT COVER.
NOTE:
• Pay special attention not to break or damage on the FRONT
PANEL.
• The LCD PANEL UNIT is fixed to the FRONT COVER (at the
back side)by using double-side adhesive tapes. To remove
the LCD PANEL UNIT, remove the adhesive tape on the
FRONT COVER slowly.

1-10 (No.YA354)
D
E
F
G
J
K
O
N
M
L
H
A
C
B
N
O
P
HANDLE
LED LENS
CABLE
HOLDER
HINGE COVER
FOOT TOP COVER
FOOT ASSEMBLY
SPEAKER
FRONT COVER
LCD PANEL UNIT
SIDE AV COVER
CARD SLOT
COVER
BUTTON FUNCTION
SIDE CONTROL PWB
AV JACK PWB
AV JACK
BRACKET
MAIN PWB
METAL HANG
BACK DOOR
TERMINAL BOARD
BACK COVER
LED PWB
SPEAKER

(No.YA354)1-11
3.2 MEMORY IC REPLACEMENT
• This model uses the memory IC.
• This memory IC stores data for proper operation of the video and drive circuits.
• When replacing, be sure to use an IC containing this (initial value) data.
3.2.1 SETTINGS OF FACTORY SHIPMENT
3.2.1.1 BUTTON OPERATION 3.2.1.2 REMOTE CONTROL DIRECT OPERATION
3.2.1.3 REMOTE CONTROL MENU OPERATION
(1) PICTURE
(2) SOUND
(3) FEATURES
(4) Install [TV MODE]
(5) Install [EXT MODE]
Setting item Setting position
POWER Off
TV/AV TV
Setting item Setting position
ZOOM AUTO
Setting item Setting position
MODE Bright
Contrast 33 Step
Bright-1 26 Step
Sharpness 11 Step
Colour 36 Step
Bright-2 7 Step
Colour Temp. Cool
Nolse Red. Min
Setting item Setting position
Volume 10 Step
Bass 16 Step
Treble 15 Step
Balance 16 Step
Hyper Sound Off
Sound Mode Mono
Setting item Setting position
Sleep Timer Off
Child Lock Off
Language English
EXT-2 Output TV
Blue Back Off
Setting item Setting position
Colour System Auto
Decorder(EXT-2) On
VCR Off
Setting item Setting position
Colour System Auto
VCR Off

1-12 (No.YA354)
3.3 REPLACEMENT OF CHIP COMPONENT
3.3.1 CAUTIONS
(1) Avoid heating for more than 3 seconds.
(2) Do not rub the electrodes and the resist parts of the pattern.
(3) When removing a chip part, melt the solder adequately.
(4) Do not reuse a chip part after removing it.
3.3.2 SOLDERING IRON
(1) Use a high insulation soldering iron with a thin pointed end of it.
(2) A 30w soldering iron is recommended for easily removing parts.
3.3.3 REPLACEMENT STEPS
1. How to remove Chip parts
[Resistors, capacitors, etc.]
(1) As shown in the figure, push the part with tweezers and
alternately melt the solder at each end.
(2) Shift with the tweezers and remove the chip part.
[Transistors, diodes, variable resistors, etc.]
(1) Apply extra solder to each lead.
(2) As shown in the figure, push the part with tweezers and
alternately melt the solder at each lead. Shift and remove
the chip part.
NOTE :
After removing the part, remove remaining solder from the
pattern.
2. How to install Chip parts
[Resistors, capacitors, etc.]
(1) Apply solder to the pattern as indicated in the figure.
(2) Grasp the chip part with tweezers and place it on the
solder. Then heat and melt the solder at both ends of the
chip part.
[Transistors, diodes, variable resistors, etc.]
(1) Apply solder to the pattern as indicated in the figure.
(2) Grasp the chip part with tweezers and place it on the
solder.
(3) First solder lead Aas indicated in the figure.
(4) Then solder leads Band C.
SOLDER SOLDER
A
B
C
A
B
C

(No.YA354)1-13
SECTION 4
ADJUSTMENT
This service manual does not describe ADJUSTMENT.
SECTION 5
TROUBLESHOOTING
This service manual does not describe TROUBLESHOOTING.

(No.YA354)
AV & MULTIMEDIA COMPANY DISPLAY CATEGORY 12, 3-chome, Moriya-cho, Kanagawa-ku, Yokohama-city, Kanagawa-prefecture, 221-8528, Japan
Victor Company of Japan, Limited
VPT
Printed in Japan

COPYRIGHT © 2005 Victor Company of Japan, Limited No.YA354
2005/11
WIDE LCD PANEL TELEVISION
YA354200511
LT-20DA6SK
P
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PC
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RM-C1896
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AV
DVDVCR TV
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SCHEMATIC DIAGRAMS
CD-ROM No.SML200511

(No.YA354)2-1
5.NOTE FOR REPAIRING SERVICE
This model's power circuit is partly different in the GND. The
difference of the GND is shown by the LIVE : ( ) side GND and the
ISOLATED(NEUTRAL): ( ) side GND. Therefore, care must be
taken for the following points.
(1)Do not touch the LIVE side GND or the LIVE side GND and the
ISOLATED(NEUTRAL)side GND simultaneously. if the above
caution is not respected, an electric shock may be caused.
Therefore, make sure that the power cord is surely removed from
the receptacle when, for example, the chassis is pulled out.
(2)Do not short between the LIVE side GND and ISOLATED(NEUTRAL)
side GND or never measure with a measuring apparatus measure
with a measuring apparatus ( oscilloscope, etc.) the LIVE side GND
and ISOLATED(NEUTRAL)side GND at the same time.
If the above precaution is not respected, a fuse or any parts will be broken.
Since the circuit diagram is a standard one, the circuit and
circuit constants may be subject to change for improvement
without any notice.
NOTE
Due improvement in performance, some part numbers show
in the circuit diagram may not agree with those indicated in
the part list.
When ordering parts, please use the numbers that appear
in the Parts List.
STANDARD CIRCUIT DIAGRAM
NOTE ON USING CIRCUIT DIAGRAMS
(7)Ground symbol
: LIVE side ground
: ISOLATED(NEUTRAL)side ground
: EARTH ground
: DIGITAL ground
(6)Connecting method
: Connector : Wrapping or soldering
: Receptacle
(5)Test point
: Test point : Only test point display
Respective voltage values are indicated
: B1
: 9V : 5V
: B2 (12V)
(4)Power Supply
Type
MM : Metalized mylar capacitor
PP : Polypropylene capacitor
MPP : Metalized polypropylene capacitor
MF : Metalized film capacitor
TF : Thin film capacitor
BP : Bipolar electrolytic capacitor
TAN : Tantalum capacitor
(3)Coils
No unit
Others
: [µH]
: As specified
No indication : Ceramic capacitor
(2)Capacitors
Capacitance value
1 or higher : [pF]
less than 1 : [µF]
Withstand voltage
No indication : DC50[V]
Others : DC withstand voltage [V]
AC indicated : AC withstand voltage [V]
Electrolytic Capacitors
47/50[Example]: Capacitance value [µF]/withstand voltage[V]
Composition resistor 1/2 [W] is specified as 1/2S or Comp.
Type
No indication : Carbon resistor
OMR : Oxide metal film resistor
MFR : Metal film resistor
MPR : Metal plate resistor
UNFR : Uninflammable resistor
FR : Fusible resistor
4.INDICATIONS ON THE CIRCUIT DIAGRAM
(1)Resistors
Resistance value
No unit : [Ω]
K: [kΩ]
M
Rated allowable power
No indication : 1/16 [W]
Others : As specified
: [MΩ]
3.INDICATION OF PARTS SYMBOL [EXAMPLE]
In the PW board : R209 R209
1.SAFETY
The components identified by the symbol and shading are
critical for safety. For continued safety replace safety ciritical
components only with manufactures recommended parts.
Since the voltage values of signal circuit vary to some extent
according to adjustments, use them as reference values.
2.SPECIFIED VOLTAGE AND WAVEFORM VALUES
The voltage and waveform values have been measured under the
following conditions.
(1)Input signal : Colour bar signal
(2)Setting positions of
each knob/button and
variable resistor
(3)Internal resistance of tester : DC 20kΩ/V
(4)Oscilloscope sweeping time : H 20µs / div
: V 5ms / div
: Othters Sweeping time is
specified
(5)Voltage values : All DC voltage values
: Original setting position
when shipped
LT-20DA6SK

SEMICONDUCTOR SHAPES
CONTENTS
SEMICONDUCTOR SHAPES ......................................................................2-2
BLOCK DIAGRAM [TV PARTS] ..................................................................2-3
BLOCK DIAGRAM [IDTV PARTS]...............................................................2-5
CIRCUIT DIAGRAMS
MAIN PWB CIRCUIT DIAGRAM ................................................................................................................ 2-7
SIDE CONTROL PWB CIRCUIT DIAGRAM ............................................................................................. 2-31
LED PWB CIRCUIT DIAGRAM ................................................................................................................. 2-31
AV JACK PWB CIRCUIT DIAGRAM ......................................................................................................... 2-32
PATTERN DIAGRAMS
MAIN PWB PATTERN .............................................................................................................................. 2-33
SIDE CONTROL PWB PATTERN ............................................................................................................. 2-37
LED PWB PATTERN ................................................................................................................................ 2-37
AV JACK PWB PATTERN ........................................................................................................................ 2-37
USING P.W. BOARD
P.W.B ASS’Y name
MAIN P.W. BOARD
SIDE CONTROL P.W. BOARD
LED P.W. BOARD
AV JACK P.W. BOARD
VE-20228287
VE-20224821
VE-20220627
VE-20224823
LT-20DA6SK
IC
BOTTOM VIEW FRONT VIEW TOP VIEW
1 N
N
1
OUT
E
IN
IN OUTE
1 N
TOP VIEW
1
N
1
N
CHIP IC
TRANSISTOR
BOTTOM VIEW FRONT VIEW TOP VIEW
CHIP TR
E
C
B
ECB
C
BE
B
(G)
E
(S)
C
(D)
ECB
ECB
2-2(No.YA354)

2-4(No.YA354)(No.YA354)2-3
L
8 ohm
6W
R
8 ohm
6W
CONTROLLER
SDA5550M
Audio
Processor
MSP34x0
LVDS
VIDEO
DECODER
VPC3230
SCALER
DEINTERLACER
GM6015
Power Supply
PLL
TUNER IF FRONTEND
TDA9886T
LED
CARD
KEYPAD
CARD
INVERTER
20"W
TFT-LCD
PANEL
PL301
IR_IN
LED
PL302
MENU
P+
P-
V+
V-
SOURCE
POWER
R(0-7)
B(0-7)
G(0-7)
DCLK
D_VSYNC
D_HSYNC
DE
PL702 PL703
+12V
+5V
3.3V
2.5V
1.8V
S+5V
S3.3V
S2.5V
S1.8V
+12V
SCART 2 AV AUDIO IN/OUT
RCA_CVBS
RCA AUDIO IN/OUT
ADC
AD9883
FLASH
V G AA V
I
2
C
I
2
C
I
2
C
I
2
C
I
2
C
Audio
Amplifier
2x3W
SCART 2
EE
PROM
SDRAM
PORTB
PORTA
I
2
C
BT656
RGB
SWITCH 1
RGB
SWITCH 2
SCART 2
CVBS IN/OUT
SCART1
RGB IN
OSD
GENERATOR
MC14
SCART 1
CVBS IN/OUT
SCART 2
RGB IN
I
2
C
SVHS / Y
I
2
C
HEADPHONE OUT
SCART 1 AV
AUDIO IN/OUT
I
2
C
24Bit RGB
AUDIO
SCART 1 SVHS
VIDEO
MATRIX
SWITCH
SVHS / C
I
2
C
CVBS IF
CVBS IF
SCART 2 C
CVBS / Y
C
TV LINK
AUDIO
MUX
AUDIO
MUX
DDC
EE
PROM
FROM STi5518
BT-601 8-bit, HS,VS
Serial Interface
RX,TX,IRQ
To STi5518
AUDIO
L/R
CVBS IF
FROM
STi5518
CVBS
FROM
PCM
DAC
AUDIO
L/R
AUDIO
L/R
BLOCK DIAGRAM [TV PARTS]

(No.YA354)2-5 2-6(No.YA354)
CONTROLLER
&
MPEG DECODER
STi5518
DIGITAL
TUNER
DIGITAL
FRONTEND
ST0360
+12V
+5V
3.3V
2.5V
1.8V
S+5V
S3.3V
S2.5V
S1.8V
IF
FC_DATA(0-7)
FC_CLK
FC_SYNC
FC_VALID
CMD(0-7)
CMD_CLK
CMD_SYNC
CMD_VALID BT-601 8-bit, HS,VS
PCM/I2S
AUDIO
L/R
CI CONNECTOR
EMI DRAM
SMI DRAM
FLASH
I2C
I2C
EE
PROM
ADR&DATA
LATCH
ADR
(0-14)
CPU_
DATA
(0-7)
MDIA_D(0-7)
MDOA_D(0-7)
MA_A(0-14)
CI
CARD
INTERFACE
STV0700
I
2C
I2C
PCM
DAC
I
2C
CVBS
TO VIDEO
MATRIX
TO
AUDIO
SWITCH
TO GM6015 PORT B
FROM
POWER
SUPPLY
Serial Interface RX,TX,IRQ
TO SDA 5550 CONTROLLER
BLOCK DIAGRAM [IDTV PARTS]

2-8(No.YA354)(No.YA354)2-7
MAIN PWB ASS'Y (1/12)
VE-20228287
CIRCUIT DIAGRAMS
MAIN PWB CIRCUIT DIAGRAM (1/12)