JVC LT-20DJ5SGE User manual

SERVICE MANUAL
COPYRIGHT © 2006 Victor Company of Japan, Limited No.YA437
2006/6
LCD PANEL TELEVISION
YA43720066
LT-20DJ5SGE,
LT-20DJ5SFR,
LT-20DJ5SSP
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Preliminary

1-2 (No.YA437)
SPECIFICATION
Design & specifications are subject to change without notice.
Items Contents
Dimensions ( W ×H ×D ) 53.0cm ×47.7cm ×21.3cm [Included stand]
53.0cm ×44.0cm ×12.5cm [TV only]
Mass 8.2kg [Included stand]
7.2kg [TV only]
Power Input ADAPTER
TV
AC100 - 240V, 50Hz
DC12V
Power Consumption 60W (Standby: 3.0W)
TV RF System Analog
Digital
CCIR (B/G, I, D/K, L)
DVB-T 2k&8k
Colour System PAL, SECAM, NTSC 3.58/4.43 [EXT only]
Stereo System NICAM (B/G, I, D/K, L), A2 (B/G, D/K)
Receiving Frequency Analog
Digital
CATV
VHF: 47 MHz - 470 MHz
UHF: 470 MHz - 862 MHz
UHF: 474 MHz - 858 MHz
68 MHz - 174 MHz, 230 MHz - 470 MHz
Intermediate
Frequency
VIF
SIF
38.9 MHz (B/G, I, D/K, L)
33.4 MHz (5.5 MHz: B/G)
32.9 MHz (6.0 MHz: I)
32.4 MHz (6.5 MHz: D/K, L)
Colour Sub
Carrier Frequency
PAL
SECAM
NTSC
4.43 MHz
4.40625 MHz / 4.25MHz
3.58 MHz / 4.43 MHz
Teletext System Analog
Digital
TOP, FLOF (Fastext level 2.5), WST(World Standard system)
Digital Teletext (VBI insertion)
LCD panel 20V-inch (4:3)
Screen Size Diagonal : 50.9cm (H:40.8cm ×V : 30.6cm)
Display Pixels Horizontal : 800 dots ×Vertical : 600 dots (SVGA)
Audio Power Output 5W + 5W(10% THD)
Speaker 3.0cm ×10.0cm oval type ×2
Aerial terminal (VHF/UHF) EU-type connector, 75Ωunbalanced, coaxial
EXT-1 / EXT-2 (Input / Output) 21-pin Euro connector (SCART socket ) ×2
EXT-3(Input) Component Video
625p / 525p / 625i / 525i
Audio
RCA pin jack ×3
Y : 1V (p-p), Positive (Negative sync provided), 75 Ω
Cb/Cr : 0.7V(p-p), 75 Ω
500mV(rms) (-4dBs), high 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 >
Horizontal : 30kHz - 69kHz
Vertical : 50Hz - 75Hz
[Resolution : 640 pixels × 480 pixels(VGA), 720 pixels × 400 pixels, 800 pixels × 600 pixels(SVGA)]
PC AUDIO input 3.5mm stereo mini jack ×1
Audio output Analog
Digital
500mV (rms), Low impedance, RCA pin jack ×2
AC3 compatible, RCA pin jack ×1
Headphone 3.5mm stereo mini jack ×1
Card Slot CAM(Conditional Access Module) ×1
Remote Control Unit RM-C1897S (AA/R6 dry cell battery ×2)

(No.YA437)1-3
SECTION 1
PRECAUTION
1.1 SAFETY PRECAUTIONS [EXCEPT FOR UK]
(1) The design of this product contains special hardware,
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 products 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 products have
special safety-related characteristics. These
characteristics are often not evident from visual inspection
nor can the protection afforded by them necessarily 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 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) Don't short between the LIVE side ground and
ISOLATED (NEUTRAL) side ground or EARTH side
ground when repairing.
Some model's power circuit is partly different in the GND.
The difference of the GND is shown by the LIVE : ( ) side
GND, the ISOLATED (NEUTRAL) : ( ) side GND and
EARTH : ( ) side GND.
Don't short between the LIVE side GND and ISOLATED
(NEUTRAL) side GND or EARTH side GND and never
measure the LIVE side GND and ISOLATED (NEUTRAL)
side GND or EARTH side GND at the same time with a
measuring apparatus (oscilloscope etc.). If above note will
not be kept, a fuse or any parts will be broken.
(5) When service is required, observe the original lead dress.
Extra precaution should be given to assure correct lead
dress in the high voltage circuit area. Where a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the
manufacturer's replacement components.
(6) Isolation Check (Safety for Electrical Shock Hazard)
After re-assembling the product, always perform an
isolation check on the exposed metal parts of the cabinet
(antenna terminals, video/audio input and output terminals,
Control knobs, metal cabinet, screw heads, earphone jack,
control shafts, etc.) to be sure the product is safe to operate
without danger of electrical shock.
a) Dielectric Strength Test
The isolation between the AC primary circuit and all metal
parts exposed to the user, particularly any exposed metal
part having a return path to the chassis should withstand a
voltage of 3000V AC (r.m.s.) for a period of one second. (.
. . . Withstand a voltage of 1100V AC (r.m.s.) to an
appliance rated up to 120V, and 3000V AC (r.m.s.) to an
appliance rated 200V or more, for a period of one second.)
This method of test requires a test equipment not generally
found in the service trade.
b) Leakage Current Check
Plug the AC line cord directly into the AC outlet (do not use
a line isolation transformer during this check.). Using a
"Leakage Current Tester", measure the leakage current
from each exposed metal part of the cabinet, particularly
any exposed metal part having a return path to the chassis,
to a known good earth ground (water pipe, etc.). Any
leakage current must not exceed 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).
Alternate Check Method
Plug the AC line cord directly into the AC outlet (do not
use a line isolation transformer during this check.). Use
an AC voltmeter having 1000Ωper volt or more
sensitivity in the following manner. Connect a 1500Ω
10W resistor paralleled by a 0.15µF AC-type capacitor
between an exposed metal part and a known good earth
ground (water pipe, etc.). Measure the AC voltage
across the resistor with the AC voltmeter. Move the
resistor connection to each exposed metal part,
particularly any exposed metal part having a return path
to the chassis, and measure the AC voltage across the
resistor. Now, reverse the plug in the AC outlet and
repeat each measurement. Any voltage measured must
not exceed 0.75V AC (r.m.s.). This corresponds to
0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.3V AC
(r.m.s.). This corresponds to 0.2mA AC (r.m.s.).
AC VOLTMETER
(HAVING 1000 /V,
OR MORE SENSITIVITY)
PLACE THIS PROBE
ON EACH EXPOSED
METAL PART
1500 10W
0.15 F AC-TYPE
GOOD EARTH GROUND

1-4 (No.YA437)
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.YA437)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.YA437)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 FEATURES
DVB-T (DIGITAL TERRESTRIAL BROADCASTING)
This TV can receive both Digital terrestrial broadcasting (DVB-
T) and Analogue terrestrial broadcasting.
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
(TV-LINK)
11 G input 700mV(B-W), 75ΩUsed Used
12 SDA Not used Not used
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 (C/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 (V1) Used (Y/V2)
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.YA437)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 500 : 1
Response time 16ms
View angle Horizontally: 160°, Vertically: 120°

1-8 (No.YA437)
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 HANDLE
• Remove the HINGE COVER.
• Remove the FOOT TOP COVER.
(1) Remove the 4 screws [D].
(2) Remove the THE HANDLE.
3.1.5 REMOVIE BACK COVER
• Remove the FOOT ASSEMBLY.
(1) Remove the 7 screws [E].
(2) Remove the BACK COVER toward you.
NOTE:
If necessary, remove the HANDLE 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 FUNCTION BUTTON with SIDE CONTROL
PWB.
(3) Remove the 4 claws which is fixing the SIDE CONTROL
PWB.
(4) Remove the SIDE CONTROL PWB.
3.1.7 REMOVING THE AV JACK PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 4 screws [G].
(2) Remove the AV JACK PWB.
3.1.8 REMOVING THE METAL HANG
• Remove the FOOT ASSEMBLY.
• Remove the HANDLE.
• Remove the BACK COVER.
(1) Remove the 1 screw [H].
(2) Remove the METAL HANG.
(3) Remove the opposite METAL HANG same steps.
3.1.9 REMOVING THE BRACKET SOCKET COVER
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [J].
(2) Remove the BRACKET SOCKET COVER.
3.1.10 REMOVING THE MAIN PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
• Remove the BRACKET SOCKET COVER.
(1) Remove the 9 screws [K].
(2) Remove the MAIN PWB.
3.1.11 REMOVING THE LED PWB
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the 2 screws [L].
(2) Remove the LED PWB.
3.1.12 REMOVING THE SPEAKER
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
(1) Remove the speaker wire from speaker terminal.
(2) Remove the 2 screws [M].
(3) Remove the SPEAKER.
(4) Remove the opposite speaker same steps.
3.1.13 REMOVING THE LCD PANEL UNIT
• Remove the FOOT ASSEMBLY.
• Remove the BACK COVER.
• Remove the MAIN PWB.
(1) Remove the 2 screws [N].
(2) Remove the INVERTER UNIT.
(3) Remove the 4 screws [P].
(4) Remove the 5 screws [Q] fixing the DISPLAY SUPPORT
and LCD PANEL UNIT.
(5) Sightly raise the both sides of the LCD PANEL by hand
from the FRONT COVER.
NOTE:
• Pay special attention not to break or damage on the front of
the LCD 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.

(No.YA437)1-9
D
E
HANDLE
BACK COVER
F
K
P
J
C
METAL HANG
FOOT ASSEMBLY
FOOT TOP
COVER
HINGE
COVER
CABLE
HOLDER
BACK DOOR
SPEAKER
LED PWB
LED LENS
SIDE CONTROL PWB
FUNCTION BUTTON
H
L
M
AV JACK PWB
BRACKET SOCKET
COVER
MAIN PWB
LCD PANEL UNIT
DISPLAY SUPPORT
FRONT COVER
G
A
P
Q
B
INVERTER
UNIT
N
CARD
SLOT
DOOR

1-10 (No.YA437)
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) FEATURE
(4) INSTALLATION
Setting item Setting position
POWER Off
TV/AV TV
Setting item Setting position
ZOOM Auto
Hyper Sound Off
Setting item Setting position
Mode Bright
Colour Temp. Cool
Noise Red. Minimum
Setting item Setting position
Hyper Sound Off
Sound Mode Mono
Setting item Setting position
Sleep Timer Off
Child Lock Off
Language English
EXT-2 Output TV
Blue Back On
Setting item Setting position
Colour System AUTO
Decoder(EXT-2) Off
VCR Off

(No.YA437)1-11
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

1-12 (No.YA437)
SECTION 4
ADJUSTMENT
4.1 ADJUSTMENT PREPARATION
(1) There are 2 ways of adjusting this TV : One is with the REMOTE
CONTROL UNIT and the other is the conventional method using
adjustment parts and components.
(2) The adjustment using the REMOTE CONTROL UNIT is
made on the basis of the initial setting values. The setting
values which adjust the screen to the optimum condition
can be different from the initial setting values.
(3) Make sure that connection is correctly made AC to AC
power source.
(4) Turn on the power of the TV and measuring instruments for
warming up for at least 30 minutes before starting adjustments.
(5) If the receive or input signal is not specified, use the most
appropriate signal for adjustment.
(6) Never touch the parts (such as variable resistors,
transformers and condensers) not shown in the
adjustment items of this service adjustment.
4.2 BASIC OPERATION OF SERVICE MODE
4.2.1 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.
4.2.2 HOW TO EXIT THE SERVICE MODE
Press the [MENU] key to exit the Service mode.
4.2.3 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
4.2.4 SERVICE MODE SELECT KEY LOCATION
SERVICE MODE SCREEN
Service
Adjust ...
Option ...
Aps Wss Test ...
JVC20 AU EUIDTV 0.289P2
May 25 2006 17:52:36
[OK]
[FUNCTION ] [FUNCTION ]
[INFORMATION]
[MUTING]
[MENU]

(No.YA437)1-13
4.2.5 SERVICE MODE SETTING ITEMS
SECTION 5
TROUBLESHOOTING
This service manual does not describe TROUBLESHOOTING.
Setting menu Setting items Setting menu Setting items
Adjust Group Option 2 Carrier
Mode LDLY
Col Temp AGC
Contrast Other
Brightness PC
Colour Osdclk_Dly
Sharpness Osdclk_pinDly
Red MAD
Green Aps Wss Test Programme
Blue VPS
Aps Volume Scart Volume Avl Off
Option 1 First APS Pdc Format 1
FM Prs Avl On Pdc Format 2
Nicam Prs Avl On Name
Scart Prs Avl On WSS
Scart Volume Avl On
FM Prs Avl Off
Nicam Prs Avl Off
Scart Prs Avl Off
Scart Volume Avl Off
Avl
Sound

(No.YA437)
Flat Panel 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

(No.YA437)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-20DJ5SGE, LT-20DJ5SFR, LT-20DJ5SSP
Preliminary

SEMICONDUCTOR SHAPES
CONTENTS
SEMICONDUCTOR SHAPES ......................................................................2-2
WIRING DIAGRAM ........................................................................................2-3
BLOCK DIAGRAM [TV PART].....................................................................2-5
BLOCK DIAGRAM [IDTV PART] .................................................................2-7
CIRCUIT DIAGRAMS
MAIN PWB CIRCUIT DIAGRAM ................................................................................................................ 2-9
SIDE CONTROL PWB CIRCUIT DIAGRAM ............................................................................................. 2-33
AV & HEADPHONE PWB CIRCUIT DIAGRAM ......................................................................................... 2-34
PATTERN DIAGRAMS
MAIN PWB PATTERN .............................................................................................................................. 2-35
SIDE CONTROL PWB PATTERN ............................................................................................................. 2-39
AV & HEADPHONE PWB PATTERN ......................................................................................................... 2-39
USING P.W. BOARD
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
P.W.B ASS’Y name
MAIN P.W. BOARD
SIDE CONTROL P.W. BOARD
AV & HEADPHONE P.W. BOARD
VE-20267685
VE-20224821
VE-20242334
LT-20DJ5SGE LT-20DJ5SFR LT-20DJ5SSP
2-2(No.YA437)

2-4(No.YA437)(No.YA437)2-3
WIRING DIAGRAM

(No.YA437)2-5 2-6(No.YA437)
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
17"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 PART]

2-8(No.YA437)(No.YA437)2-7
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
I2C
I2C
PCM
DAC
I2C
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 PART]

(No.YA437)2-9 2-10(No.YA437)
c17mb16p-2_0602_1/12_0.0
MAIN PWB ASS'Y(1/12)
VE-20267685
CIRCUIT DIAGRAMS
MAIN PWB CIRCUIT DIAGRAM (1/12) SHEET1