JVC InteriArt LT-26C31BC User manual

SERVICE MANUAL
COPYRIGHT © 2004 Victor Company of Japan, Limited No.YA169
2004/8
WIDE LCD PANEL TELEVISION
YA16920048
LT-26C31BC
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46
BASIC CHASSIS
MK

1-2 (No.YA169)
SPECIFICATION
Design and specifications subject to change without notice.
Items Contents
Dimensions (W ×H ×D) 70.3 cm ×56.0 cm ×2.6 cm (Included stand)
70.3 cm ×49.1 cm ×9.4 cm (TV only)
Mass 19.0 kg (Included stand)
18.3 kg (TV only)
TV RF System CCIR B/G, I, D/K, L
Colour System PAL / SECAM / NTSC 3.58 / NTSC 4.43 (NTSC:EXT only).
Stereo System A2 (B/G, D/K), NICAM (B/G, I, D/K, L)
Teletext System FLOF (Fastext), TOP, WST (World Standard System)
Receiving
Frequency
VHF
UHF
CATV
47MHz ~ 470MHz
470MHz ~ 862MHz
116MHz ~ 172MHz / 220MHz ~ 469MHz
Intermediate
Frequency
VIF
SIF
38.9MHz(B/G, D/K, I)
33.4MHz(5.5MHz:B/G) / 32.9MHz(6.0MHz:I) / 32.4MHz(6.5MHz:L,D/K)
Colour Sub
Carrier Frequency
PAL
SECAM
NTSC
4.43MHz
4.40625MHz / 4.25MHz
3.58MHz / 4.43MHz
Power Input AC110V - AC240 V, 50 Hz / 60 Hz
Power Consumption 148 W [Standby: 2.8 W]
Aerial Input 75 Ωunbalanced, coaxial
Screen Size Diagonal: 66 cm (H: 33.9cm ×V: 56.6cm)
Display Resolution Horizonal : 1280 dots ×Vertical : 768 dots (W-XGA)
Speaker 6.6 cm round ×2 (Oblique corn)
Audio Power Output 10 W + 10 W (Rated power output)
EXT-1 (Input/Output) 21 pin Euro connector (SCART socket)
Video input, Audio L/R inputs and RGB inputs are available.
TV broadcast outputs (Video and Audio L/R) are available.
EXT-2 (Input/Output) 21 pin Euro connector (SCART socket)
Video input, S-VIDEO (Y/C) input, Audio L/R inputs and RGB inputs are available.
Video and Audio L/R outputs are available.
T-V LINK functions are available.
EXT-3 (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
EXT-4 (Input) Component video
Audio (L/R)
RCA pin jack ×3
Y : 1V(p-p), 75 Ω
Pb / B-Y: 0.7V(p-p), 75 Ω
Pr / R-Y : 0.7V(p-p), 75 Ω
Component video (Pr, Pb, Y) inputs (625p, 525p, 1125i) and Audio L/R inputs are available.
525p and 625p are progressive scanning signals. Some DVD players can output these signals.
1125i is one of the new high-definition signals.
500mV(rms) (-4dBs), High impedance, RCA pin jack ×2
AUDIO OUT terminal 500mV(rms), Low impedance, RCA pin jack ×2
Headphone jack 3.5 mm stereo mini jack ×1
Remote Control Unit RM-C1808 (AA/R6 dry cell battery ×2)

(No.YA169)1-3
SECTION 1
PRECAUTION
1.1 SAFETY PRECAUTIONS
(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) If any repair has been made to the chassis, it is
recommended that the B1 setting should be checked or
adjusted (See B1 POWER SUPPLY check).
(6) The high voltage applied to the picture tube must conform
with that specified in Service manual. Excessive high
voltage can cause an increase in X-Ray emission, arcing
and possible component damage, therefore operation
under excessive high voltage conditions should be kept to
a minimum, or should be prevented. If severe arcing
occurs, remove the AC power immediately and determine
the cause by visual inspection (incorrect installation,
cracked or melted high voltage harness, poor soldering,
etc.). To maintain the proper minimum level of soft X-Ray
emission, components in the high voltage circuitry
including the picture tube must be the exact replacements
or alternatives approved by the manufacturer of the
complete product.
(7) Do not check high voltage by drawing an arc. Use a high
voltage meter or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground frame
and connecting the other end of the lead through a 10kΩ
2W resistor to the anode button.
(8) 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.
(9) 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.YA169)
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.
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
To ensure safety in an emergency such as an earthquake, and to prevent accidents, ensure that measures are taken to prevent the
TV dropping or falling over.
Use the supplied screws to firmly attach the supplied hooks to the back of the TV, and use commercially available cord to fix the TV
to rigid components such as walls and columns.
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.
Distance recommendations
Avoid improper installation and never position the unit where good
ventilation is impossible.
When installing this TV, distance recommendations must be maintained
between the set and the wall, as well as inside a tightly enclosed area or
piece of furniture.
Keep to the minimum distance guidelines shown for safe operation.
200 mm 200 mm
50 mm
150 mm 150 mm
Supplied hooks

(No.YA169)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.YA169)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
2.1 FEATURES
2.1.1 FUNCTION / CIRCUITS
• DIST (Digital Image Scaling Technology) employs an interpolation
method that doubles the scanning lines to realize 1250-line flicker-
free picture making it especially suitable for reproducing high-
resolution pictures even on large-screen displays.
• New chassis design enable use of an interactive on screen
control.
• The TELETEXT SYSTEM has a built-in FASTEXT (UK
system), TOP (German system) and WST (world standard
system) system.
• Because this TV unit corresponds to multiplex broadcast,
users can enjoy music programs and sporting events with live
realism. In addition, BILINGUAL programs can be heard in
their original language.
• Users can make VCR dubbing of picture and sound by
controlling the AV selector to select an optional source at the
EXT-2 output shown in figure.
2.1.2 21-PIN EURO CONNECTOR (SCART) : EXT-1/EXT-2
(P-P= Peak to Peak, B-W= Blanking to white peak)
TV EXT-1 EXT-3
EXT-2
EXT-4
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.YA169)1-7
2.2 TECHNICAL INFORMATION
2.2.1 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.
2.2.1.1 STRUCTURE
The LCD panel of the unit is constructed with the metal chassis that surrounds the panel unit and supports the LCD panel part and
the backlight part to protect them.
The colour filter glass and the TFT glass (thin film transistor) are inserted between the front polarizing filter and the rear polarizing
filter. Liquid crystals are inserted between the colour filter glass and the TFT glass. Since the gap between the two glasses is only a
few µm, a spacer (bead) is inserted in the gap to retain the gap.
The backlight unit is placed behind the LCD panel. Since liquid crystals themselves do not emit light, the backlight as an external light
source emits light to the LCD panel from behind through the diffuser.
Circuit boards for controlling the LCD panel and the backlight are attached around the back part of the LCD panel 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.
Fig.1 Structure of the LCD panel unit
2.2.1.2 SPECIFICATIONS
The following table shows the specifications of this unit.
2.2.1.3 PIXEL FAULT
There are three pixel faults - bright fault , dark fault and flicker fault - that are respectively defined as follows.
(1) 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.
(2) 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.
(3) 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
Maximum dimensions ( W ×H ×D ) 62.7cm ×38.9cm ×4.9cm
Weight 8.0kg
Effective screen size Diagonal : 66cm (H:33.9cm ×V : 56.6cm) 26V type
Aspect ratio 15:9
Drive device/ system a-Si-TFT, active matrix system
Resolution Horizontally 1280 ×Vertically 768 ×RGB <W-XGA> 2949120 dots in total
Pixel pitch (pixel size) Horizontally:0.4425mm, Vertically:0.4425mm
Displayed colour 16777216 colours 256 colours for R, G, and B
Brightness 450cd/m2500cd/m2at maximum
Contrast ratio 500:1
Response time 16.7ms
View angle Vertically 170°, horizontally 170°
Top chassis
Source board
Panel ASSY
Diffuser (including board)
Upper frame
Lower frame
Lamp supporter
Diffuser supporter
Reflection plate
Inverter board
Sield case
Inverter shield cover

1-8 (No.YA169)
2.2.2 MAIN CPU PIN FUNCTION (IC001)
Pin No. Pin Name I/O Remark
1 TCK I Test purpose
2 TMS I Test purpose
3 TDI I Test purpose
4 TDO O Test purpose
5 P2.8 I Remote control input
6 P2.9 I Mechanical power switch detection [Pushing:L]
7 P2.10 I IP error detection [Detection:L]
8 P2.11 O IP reset
9 P2.12 I TV-LINK communication
10 P2.13 I Power ON/OFF [ON:L]
11 P2.14 I Low B protect detection [Detection:L]
12 P2.15 I Power condition check [ON:L]
13 VSS33 I GND
14 VDD33 I 3.3V
15 P4.5 O TV-LINK communication
16 A20 O Memory (Program ROM) address
17 A19 O Memory (Program ROM) address
18 A18 O Memory (Program ROM) address
19 A17 O Memory (Program ROM) address
20 VSS25 I GND
21 VDD25 I 2.5V
22 A16 O Memory (Program ROM) address
23 A8 O Memory (Program ROM) address
24 A7 O Memory (Program ROM) address
25 A9 O Memory (Program ROM) address
26 A6 O Memory (Program ROM) address
27 A5 O Memory (Program ROM) address
28 A10 O Memory (Program ROM) address
29 A11 O Memory (Program ROM) address
30 A12 O Memory (Program ROM) address
31 VSS33 I GND
32 VDD33 I 3.3V
33 A4 O Memory (Program ROM) address
34 A3 O Memory (Program ROM) address
35 A2 O Memory (Program ROM) address
36 A1 O Memory (Program ROM) address
37 A0 O Memory (Program ROM) address
38 A13 O Memory (Program ROM) address
39 RAS/A14 O Memory (Program ROM) address
40 CAS/A15 O Memory (Program ROM) address
41 VSS33 I GND
42 VDD33 I 3.3V
43 MEMCLK O Clock for memory
44 CSSDRAM O Chip select for memory
45 CLKEN O Clock enable for memory
46 CSROM O Chip select for memory
47 RD O Read for memory
48 UDQM O Control IN/OUT buffer of Memory (IC003)
49 LDQM O Control IN/OUT buffer of Memory (IC003)
50 WR O Write for memory
51 D15 I/O Data (Program ROM)
52 VSS33 I GND
53 VDD33 I 3.3V
54 D7 I/O Data (Program ROM)
55 D0 I/O Data (Program ROM)
56 D14 I/O Data (Program ROM)
57 D8 I/O Data (Program ROM)
58 D6 I/O Data (Program ROM)
59 D1 I/O Data (Program ROM)
60 VSS33 I GND
61 VDD33 I 3.3V
62 D13 I/O Data (Program ROM)
63 D9 I/O Data (Program ROM)
64 D5 I/O Data (Program ROM)
65 D2 I/O Data (Program ROM)
66 D12 I/O Data (Program ROM)
67 D10 I/O Data (Program ROM)
68 VSS33 I GND
69 VDD33 I 3.3V
70 D4 I/O Data (Program ROM)
71 D3 I/O Data (Program ROM)
72 D11 I/O Data (Program ROM)
73 RSTIN I Reset
74 P3.0 O I2C CLOCK 0 (for memory)
75 P3.1 I/O I2C DATA 0 (for memory)
76 P3.2 I Remote control input
77 P3.3 I Clock for OSD
78 P3.4 O Tuner system switch
79 P3.5 O Tuner system switch
80 P3.6 I Teletext mode:H
81 P3.7 I Power START
82 P3.8 I Not used
83 P3.9 I Picture mute
84 VSS33 I GND
85 VDD33 I 3.3V
86 VSS25 I GND
87 VDD25 I 2.5V
88 TXD0 O Sub micro computer communication
89 RXD0 I Sub micro computer communication
90 P3.12 I Not used
91 P3.13 I/O Not used
92 P3.15 I/O Not used
93 P5.14(YS2) I Ys for EXT-2
94 P5.15 I Headphone detection [Detection:L]
95 TRIG_IN I/O Not used
96 TRIG_OUT I/O Not used
97 P6.2 I Not used
98 P6.3 O I2C bus clock for IC control
99 P6.4 I/O I2C bus data for IC control
100 P6.5 O Multi-sound process reset
101 P6.6 I/O I2C bus data for IC control
102 VSYNC O Vertical sync for OSD
103 HSYNC O Horizontal sync for OSD
104 COR/RSTOUT O Not used
105 BLANK O Ys for OSD/Teletext
106 VDD33 I 3.3V
107 VSS33 I GND
108 XTAL1 I 6MHz
109 XTAL2 O 6MHz
110 VSSA I GND
111 VDDA I Not used
112 R O R for OSD Teletext
113 G O G for OSD Teletext
114 B I B for OSD Teletext
115 VSSA I GND
116 VDDA I 2.5V
117 CVBS2 I Video for Teletext
118 VSSA I GND
119 VDDA I 2.5V
120 CVBS1B I Video for Teletext
121 CVBS1A I Video for Teletext
122 VSSA I GND
123 VDDA I 2.5V
124 P5.0 I AFT for tuner
125 P5.1(KEY1) I Key scan data 1 [ON:H]
126 P5.2 I AGC for tuner
127 P5.3(KEY2) I Key scan data 2 [ON:H]
128 TMODE I Test purpose
Pin No. Pin Name I/O Remark

(No.YA169)1-9
2.2.3 SUB CPU PIN FUNCTION (IC7807)
Pin No. Pin name I/O Function
1 (SYSTEM0) I GND
2 (SYSTEM3) I GND
3AVCC -5V
4 X2 - Sub clock
5 X1 - Sub clock
6 VCL - Internal down voltage
7 RES I Reset [Reset : L]
8 TEST I Operation test for SUB CPU
9VSS -GND
10 OSC2 O 10MHz oscillation for system clock
11 OSC1 I 10MHz oscillation for system clock
12 VCC - 5V
13 NC O Not used
14 NC O Not used
15 BL_D2 O Back light 20ms delay for LCD panel [On:L]
16 BL_D1 O Back light 10ms delay for LCD panel [On:L]
17 I2C_STOP O Not used
18 BL_ON O Back light reset for LCD panel [Reset:L]
19 NC O Not used
20 NC O Not used
21 NC O Not used
22 NC O Not used
23 SDA1 I/O I2C bus data (For Sub memory)
24 A.DIM O Not used
25 SCL1 O I2C bus clock (For Sub memory)
26 SDA0 I/O I2C bus data (For general)
27 SCL0 O I2C bus clock (For general)
28 NC O Not used
29 NC O Not used
30 NC O Not used
31 NC O Not used
32 NC O Not used
33 NC O Not used
34 NC O Not used
35 NMI I Port for writing on board [Writning:L]
36 NC O Not used
37 (HD) I Not used
38 NC O Not used
39 (REMO) I Not used
40 NC O Not used
41 P85 -/I Not used
42 P86 - Not used
43 P87 - Not used
44 SCK3 O Port for writing on board
45 RXD I Port for writing on board
46 TXD O Port for writing on board
47 (PROTECTOR0) I Not used
48 NC O Not used
49 RXD2 I Port for communication (Main CPU)
50 TXD2 O Port for communication (Main CPU)
51 NC O Not used
52 (ACTIVE) I Not used
53 VD I Vertical sync
54 (REC_DET) I Not used
55 (PSS) I Not used
56 (ALARM) I Not used
57 (SYSTEM2) I Not used
58 (SYSTEM1) I Not used
59 (PROTECTOR1) I Not used
60 (AMP_PRO2) I Not used
61 (AMP_PRO1) I Not used
62 EE_CDS I Not used
63 (KEY_IN1) I Not used
64 (KEY_IN2) I Not used

1-10 (No.YA169)
SECTION 3
DISASSEMBLY
3.1 DISASSEMBLY PROCEDURE
CAUTION:
Since this model is a laminating structure assembly, please
perform in following order in the case of disassembling.
3.1.1 REMOVING THE STAND ASS'Y (Fig.3-1-1)
(1) Remove the 2 screws [A], and remove the COVER.
(2) Remove the 4 screws [B], and remove the STAND ASS'Y.
Fig.3-1-1
3.1.2 REMOVING THE REAR COVER (Fig.3-1-1, Fig.3-1-2)
• Remove the STAND ASS'Y.
(1) Remove the JACK COVER(R) and JACK COVER(L).
(2) Remove the 7 screws [C], 3 screws [D], 4 screws [E], and
remove the REAR COVER.
Fig.3-1-2
JACK COVER(R)
JACK COVER(L)
STAND
STAND COVER
A
B
REAR COVER
C
E
C
C
E
E
E
C
D
C
CD
DC

(No.YA169)1-11
3.1.3 REMOVING THE FAN BRACKET, REGULATOR PWB AND POWER CORD (Fig.3-1-3)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
(1) Disconnect the wire(CONN. [Y]) of COOLING FAN.
(2) Remove the 5 screws [F], and remove the FAN BRACKET.
(3) Remove the REGULATOR PWB, and disconnect the
POWER CORD.
(4) Remove the 1 screw [G], and remove the POWER CORD
HOLDER.
Fig.3-1-3
3.1.4 REMOVING THE RECEIVER PWB (Fig.3-1-4)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
(1) Remove the 2 screws [H] and 2 screws [J], then remove the
TERMINAL BASE.
(2) Remove the 5 screws [K], and remove the RECEIVER
PWB.
Fig.3-1-4
3.1.5 REMOVING THE FRONT CONTROL PWB AND FRONT SENSOR PWB (Fig.3-1-5)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
(1) Remove the 2 screws [L], and remove the CONTROL
KNOB.
(2) Remove the 3 screws [N], then remove the FRONT
CONTROL PWB and FRONT SENSOR PWB.
Fig.3-1-5
G
G
FAN BRACKET
POWER CORD
POWER CORD HOLDER
REGULATOR
PWB
COOLING FAN
F
F
G
TERMINAL BASE
RECEIVER PWB
K
H
K
J
U
T
F
HARNES( F,U,T),"S" WIRE
CLAMP
T
FRONT CONTROL PWB
EARTH PLATE
FRONT SENSOR PWB
CONTROL KNOB
M
L

1-12 (No.YA169)
3.1.6 REMOVING THE VIDEO PWB (Fig.3-1-6)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
(1) Remove the 2 screws [N] and 1 screws [P], then remove
the JACK BASE.
(2) Remove the 4 screws [Q], and remove the VIDEO PWB.
(3) Remove the 2 screws [R], and remove the TUNER PWB
BASE.
(4) Remove the 4 screws [S], and remove the TUNER PWB
and MSP PWB.
Fig.3-1-6
3.1.7 REMOVING THE MI-COM & DIST PWB (Fig.3-1-7)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
(1) Remove the 7 screws [T], and remove the VIDEO PWB
BRACKET.
(2) Remove the 4 screws [U], and remove the MI-COM & DIST
PWB from VIDEO PWB BRACKET.
Fig.3-1-7
3.1.8 REMOVING THE POWER PWB (Fig.3-1-8)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
• Remove the FUN BRACKET.
• Remove the POWER CORD.
• Remove the VIDEO PWB.
(1) Remove the 4 screws [X], and remove the AV JACK
BRACKET.
(2) Remove the 6 screws [Y], and remove the POWER PWB.
(3) Remove the 6 screws [Z], and remove the POWER PWB
BASE.
Fig.3-1-8
X
VIDEO PWB
JACK BASE
TUNER PWB
MSP PWB
TUNER PWB
BASE
QN
P
S
R
VIDEO PWB BRACKET
MI-COM&DIST PWB
U
T
T
Q
P
YY
Z
Z
X
POWER PWB
POWER PWB
BASE
AV JACK
BRACKET

(No.YA169)1-13
3.1.9 REMOVING THE SPEAKER (Fig.3-1-9A, Fig.3-1-9B)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
• Remove the POWER CORD.
(1) Remove the 5 screws [a], and remove the SPEAKER BOX.
Fig.3-1-9A
(2) Remove the 4 screws [b], and remove the SPEAKER (L/R).
(3) Remove the 4 screws [c], and remove the DUCT COVER/
DUCT BASE.
NOTE:
Since the speaker is attached in a certain direction, attach the
speaker in the same correct direction as it has been attached.
Fig.3-1-9B
SPEAKER BOX
a
a
DUCT BASE/DUCT COVER
SPEAKER
㧔R㧕
SPEAKER
㧔L㧕
c
b
b
c

1-14 (No.YA169)
3.1.10 REMOVING THE LCD PANEL (Fig.3-1-10C, Fig.3-1-10A, Fig.3-1-10B)
• Remove the STAND ASS'Y.
• Remove the REAR COVER.
• Remove the POWER CORD.
• Remove the RECEIVER PWB.
• Remove the FRONT CONTROL PWB.
• Remove the FRONT SENSOR PWB.
• Remove the VIDEO PWB.
• Remove the MI-COM & DIST PWB
• Remove the POWER PWB.
(1) Remove the 2 screws [a], and remove the 2 CENTRE
FRAMES.
Fig.3-1-10A
(2) Remove the 2 screws [b] and 2 screws [c], then remove the
RIGHT FRAME.
(3) Remove the 2 screws [b] and 2 screws [c], then remove the
LEFT FRAME.
(4) Remove the 2 screws [d], and remove the TOP FRAME.
(5) Remove the 3 screws [e] and 2 screws [f], then remove the
BOTTOM FRAME.
Fig.3-1-10B
(6) Remove the 8 screws [g] and 2 screws [h], then remove the
LCD PANEL.
NOTE:
The LCD PANEL is fixed to the FRONT PANEL (at the
back side) by using double-side adhesive tapes. To
remove the LCD PANEL, remove the adhesive tape on
the FRONT PANEL slowly.
Fig.3-1-10C
X
P
Q
CENTRE
FRAME
a
a
RIGHT
FRAME TOP
FRAME
LEFT FRAME
BOTTOM
FRAME
b
b
c
e
f
c
d
g
g
gg
h
h

(No.YA169)1-15
3.1.11 REMOVING THE LCD PANEL
3.1.11.1 REMOVING THE CONTROL PWB
• Place the LCD PANEL with its backside facing upward.
Be careful not to damage the surface of the screen.
(1) Remove the 2 screws [A], and remove the CONTROL
PWB COVER.
(2) Remove the claws in the connectors [FPC RIGHT] and
[FPC LEFT], and pull out to remove the FLEXIBLE PWB.
NOTE:
Be careful not to damage the FLEXIBLE PWB.
Especially during assembly procedure, be careful not to
insert the FLEXIBLE PWB in the Panel.
(3) Remove the 2 screws [B], and remove the CONTROL
PWB.
[Confirmation after replacement]
• Confirm that voltage of 10 pin (B/L On/Off) in the connector
[CNI1] is approx.5.0V.
• Confirm that the voltage in output of the fuses [F1] and [F2]
in the connector [CNI1] is approx.5.0V.
3.1.11.2 REMOVING THE INVERTER PWB
(1) Remove the 5 screws [C], and remove the INVERTER
PWB COVER.
(2) Pull out and remove the wires from connectors [CN4]-
[CN15] (12 connectors in total).
(3) Remove the 4 screws [D], and remove the INVERTER
PWB.
[Confirmation after replacement]
• Confirm that the voltage in output of the fuses [F1] and [F2]
in the connector [CN1] and the fuses [F3] and [F4] in the
connector [CN2] is 16V.
• Confirm that the voltage in input of the TRANSFORMER in
the Inverter Board is 8V.
• Be careful about high voltage (approx. AC900V) in output.
FUSE
OUTPUT
CONTOROL PWB
INVERTER PWB
GND
GND
8V
8V
8V
8V
TRANSFORMER
OUTPUT INPUT
CONNECTOR
A
C
D
B
CONTROL PWB COVER
INVERTER PWB COVER
CONTROL PWB
FRC
LEFT
FLEXIBLE
PWB CNT1
FUSE
(F1, F2)
FUSE
(F1, F2)
FUSE
(F3, F4)
FRC
RIGHT
CNI1
CN1
CN2
INVERTER PWB
[CN4㨪CN15]
TRANSFORMER
FRONT

1-16 (No.YA169)
3.1.11.3 REMOVING THE BACKLIGHT UNIT
NOTE:
Do not carry out the following procedure in a dusty and dirty
place.
If the surface of LCD GLASS, the surface of DIFFUSER
SHEET, and the inside of BACKLIGHT UNIT are dusty or dirty,
they cause unevenness of a displayed screen.
• Remove the CONTROL PWB.
• Remove the INVERTER PWB.
• Place the LCD UNIT with the screen facing upward.
(1) Remove the 8 screws [E], 4screws [F], and 4 screws [G]
(16 screws in total), and remove the MAIN CHASSIS.
NOTE:
Be careful not to damage the SOURCE IC and the GATE
IC on the side of LCD GLASS when removing the MAIN
CHASSIS.
(2) Remove the 6 screws [H] from the top side of the LCD
UNIT.
(3) Remove the 12 screws [I] from the sides of the LCD UNIT.
Then, LCD GLASS, DIFFUSER SHEET, and BACKLIGHT
UNIT are removed.
G
G
E
F
F
I
I
I
I
I
H
SOURCE IC
GATE IC
BACKLIGHT UNIT
DIFFUSER SHEET
LCD GLASS
MAIN CHASSIS
FRONT

(No.YA169)1-17
3.2 REPLACEMENT OF MEMORY IC
This unit uses the nonvolatile memory IC.The memory IC memories data for video and deflection circuits. To replace the memory IC
without the data written, malfunctions might occurred while power is on, and the normal image might not appear. When replacing the
memory IC, be sure to use the IC written with the initial values of data.
3.2.1 PROCEDURE FOR REPLACING THE MEMORY IC
(1) Switch the power off and unplug the power cord from the
wall outlet.
(2) Replacing the memory IC. [Be sure to use the IC written
with the initial values of data]
(3) Plug the power cord into the wall outlet and switch the
power on.
(4) Check and setting of SYSTEM CONSTANT SET
a) Press the [INFORMATION] key and [MUTING] key
on the remote control unit simultaneously.
The SERVICE MENU screen will be displayed. (See
Fig.1)
b) In the SERVICE MENU, press the [INFORMATION]
key and [MUTING] key simultaneously.
Then, the SYSTEM CONSTANT SET screen will be
displayed. (See FIg.2)
c) Check whether the setting value of the SYSTEM
CONSTANT SET is the same as these indicated in
Table 1.
d) Press the [INFORMATION] key twice to return to the
normal screen.
(5) Receive channel setting
Refer to the OPERATING INSTRUCTIONS and set the
receive channels.
(6) User setting
Memories the user setting items.The [USER SETTINGS
OF MENU] setting is as next page.
(7) Setting of SERVICE MENU
Check the setting items in the SERVICE MENU, set if
necessary.For setting method, please refer to the
[ADJUSTMENT PREPARATION] to [ADJUSTMENT
PROCEDURE] of ADJUSTMENT section.
Fig.1
Fig.2
3.2.2 SETTING OF THE SYSTEM CONSTANT SET
Table 1
3.2.3 FACTORY SHIPMENT SETTING
3.2.3.1 USER SETTING OF SWITCHS ON REMOTE CONTROL UNIT
Table 2
SERVICE MENU
1. IF 2. V/C
3. AUDIO 4. DD/CM
5. VSM PRESET 6. STATUS
7. VNR 8. IP
9. SHIPPING (OFF) 0. BUS FREE
1-9 : SELECT i : EXIT
SERVICE MENU SCREEN
SERVICE MENU SCREEN
SYSTEM CONSTANT SET SCREEN
SYSTEM CONSTANT SET SCREEN
SYSTEM CONSTANT SET
1. DESTINATION EURO
-/+ : STORE i : EXIT
OK
Setting item Setting content Setting value
DESTINATION ASIA / EURO EURO
Setting item Setting value
POWER OFF
CHANNEL PR1
PRESET CHANNEL Refer to OPERATION INSTRUCTIONS
VOLUME 10
ZOOM PANORAMIC
3D SOUND OFF

1-18 (No.YA169)
3.2.3.2 USER SETTINGS OF MENU
Table 3
3.2.3.3 VSM PRESET SETTING
Table 4
3.2.3.3.1 SETTING OF VSM PRESET
(1) Enter "5.VSM PRESET" from the SERVICE MENU.
(2) Press the [OK] key to select BRIGHT/STD/SOFT/COOL/NORMAL/WARM mode.
(3) Select the setting item using the [FUNCTION (UP/DOWN)] key.
(4) Set the value using the [FUNCTION (+/-)] key.
(5) Press the [OK] key to memorize the set value.
(6) Press the [INFORMATION] key twice to return to the normal screen.
Setting item Setting value Setting item Setting value
POWER OFF SOUND SETTING
CHANNEL PR1 BASS Centre
TREBLE Centre
PRESET CHANNEL Refer to
OPERATING INSTRUCTIONS
BALANCE Centre
SPEAKER ON
VOLUME 10 BBE ON
PICTURE SETTING 3D SOUND OFF
PICTURE MODE BRIGHT A. H. B ON
COLOUR TEMP. COOL HEADPHONE VOLUME 20
TV SPEAKER OFF
OUTPUT MAIN
PICTURE FEATURES EXT SETTING
DIGITAL VNR AUTO S-IN ---
Super DigiPure AUTO ID LIST ---
COLOUR SYSTEM TV Depends on PR/CH DUBBING EXT-1 →EXT-2
EXT AUTO FEATURES
MOVIE THEATRE AUTO SLEEP TIMER OFF
4:3 AUTO ASPECT PANORAMIC BLUE BACK ON
COLOUR MANAGEMENT ON
CHILD LOCK / CHANNEL GUARD
SET ID NO 0000
PIP POSISION Right below INSTALL
ZOOM PANORAMIC LANGUAGE ENGLISH
AUTO PROGRAM Only for preset channels
EDIT/MANUAL Only for preset channels
Item No. Setting
Item
Variable
range
Setting value
PICTURE MODE COLOUR TEMP.
BRIGHT STD SOFT COOL NORMAL WARM
1 CONT -16~16 6 0 0 - - -
2 BRIGHT -16~16 -6 0 0 - - -
3 SHARP -16~16 3 0 -2 - - -
4 COLOUR -16~16 0 0 0 - - -
5 TINT -16~16 0 0 0 - - -
6 B. LIGHT -16~16 16 16 -8 - - -
1 WDR R -64~63 - - - -8 0 0
2 WDR G -64~63 - - - -3 0 -6
3 WDR B -64~63 - - - 23 0 -3

(No.YA169)1-19
3.2.3.4 SERVICE MENU SETTING ITEMS
Table 5
Setting item Setting value Setting item Setting value
1.IF 1.VCO
2.ATT ON/OFF
6.STATUS (Do not adjust)
2.V/C 1.CUT OF R
2.CUT OF G
3.CUT OF B
4.DRIVE R
5.DRIVE G
6.DRIVE B
7.TWN HI R
8.TWN HI B
9.BRIGHT
10.CONT
11.TWN BRG
12.TWN CNT
13.COLOUR
14.HUE
15.BY GAIN
16.TWN COL
17.TWN TNT
18.B OF MR
19.B OF MB
20.B OF SR
21.B OF SB
22.M BOFST
23.M ROFST
S01 ~ S99
A01 ~ A17
PDA01 ~ PDA12
7.VNR
(Do not adjust)
1.MYLV
2.ONMVF
3.MYCOR
4.MYGA
5.YEGON
6.YEGL
7.YLTL
8.MCLV
9.MCGA
10.MCCOR
11.CLTL
12.YNGA
13.COR_OF
14.LPF_OF
15.YCTL
16.YNCL
17.YNCON
3.AUDIO
(Do not adjust)
1.ERROR LIMIT
2.A2 ID THR
3.Q-PEAK
4.SOUND LEVEL / SOUND SYSTEM B/G
8.IP
(Do not adjust)
PPA001 ~ PPA008
PPB001 ~ PPB036
PPC001 ~ PPC007
ADS001 ~ ADS034
IPA001 ~ IPA120
IPB001 ~ IPB088
IPC001 ~ IPC044
IPD001 ~ IPD058
4.DD/CM DDT01 ~ DDT34
CMT01 ~ CMT57
5.VSM PRESET PICTURE MODE
1.CONT
2.BRIGHT
3.SHARP
4.COLOUR
5.TINT
6.B. LIGHT
COLOUR TEMP.
1.WDR R
2.WDR G
3.WDR B
9.SHIPPING(OFF) (Do not use under the adjustment)

1-20 (No.YA169)
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