JVC LT-26X575/KA User manual

SERVICE MANUAL
COPYRIGHT © 2004 Victor Company of Japan, Limited No.YA179
2004/8
LCD FLAT TELEVISION
YA17920048
LT-26X575/KA,
LT-26X585/KA
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
BASIC CHASSIS
FL
[LT-26X585]

1-2 (No.YA179)
SPECIFICATION
Design & specifications are subject to change without notice.
Items Contents
Dimensions ( W ×H ×D ) 70.3cm ×55.5 cm ×30.0 cm (27-3/4 ×21-7/8 ×11-7/8) [Included stand]
70.3cm ×49.1 cm ×10.7 cm (27-3/4 ×19-3/8 ×4-1/4) [TV only]
Mass 19 kg (41.8lbs) [Included stand]
15.8kg (34.8lbs) [TV only]
Power Input AC120V , 60Hz
Power Consumption 152W (Max)
TV RF System CCIR (M)
Color System NTSC
Sound System BTSC (Multi Channel Sound)
Teletext System Closed caption (T1-T4 / CC1-CC4)
TV Receiving Channels
and Frequency
VHF Low
VHF High
UHF
CATV
02ch to 06ch : 54MHz to 88MHz
07ch to 13ch : 174MHz to 216MHz
14ch to 69ch : 470MHz to 806MHz
54MHz to 804MHz
Low Band : 02 to 06, A-8 by 02 to 06&01
High Band : 07 to 13 by 07 to 13
Mid Band : A to I by 14 to 22
Super Band : J to W by 23 to 36
Hyper Band : W+1 to W+28 by 37 to 64
Ultra Band : W+29 to W+84 by 65 to 94, 100 to 125
Sub Mid Band : A4 to A1 by 96 to 99
TV / CATV Total Channel 181 Channels
[Reception of channel A-5 (“95” of the TV set’s on-screen CABLE channel) is
recommended for your TV set.]
Intermediate Frequency Video IF
Sound IF
45.75 MHz
41.25 MHz (4.5MHz)
Color Sub Carrier 3.58 MHz
LCD panel 26V-inch wide aspect (16:9)
Screen Size Diagonal : 64.8cm (H:56.5cm ×V : 31.8cm)
Display Pixels Horizontal : 1280 dots ×Vertical : 768 dots (W-XGA)
Audio Power Output 10W + 10W
Speaker 6.6cm, round type ×2 (Oblique corn)
Antenna terminal (VHF/UHF) F-type connector, 75Ωunbalanced, coaxial
Video / Audio input
[INPUT-1/2/3]
Component Video
[INPUT-1]
1125i / 750p
525p / 525i
S-Video
[INPUT-1/2]
Video
Audio
RCA pin jack ×3
Y : 1V (p-p) (Sync signal: 0.35V(p-p), 3-value sync.), 75 Ω
Pb/Pr : ±0.35V(p-p), 75 Ω
Y : 1V (p-p), Positive (Negative sync provided), 75 Ω
Cb/Cr : 0.7V(p-p), 75 Ω
Mini-DIN 4 pin ×2
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 ×3
500mV (rms), High impedance, RCA pin jack ×6
Digital input Video
Audio
HDMI connector ×1
(Digital-input terminal is not compatible with picture signals of computer signal)
Digital: HDMI connector ×1
Anarog: 500mV(rms) (-4dBs), high impedance, RCA pin jack ×2
Audio output 500mV (rms), Low impedance, RCA pin jack ×2
Headphone 3.5mm stereo mini jack ×1
Remote Control Unit RM-C1257G (AA/R6 / UM-3 battery ×2)

(No.YA179)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) 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.YA179)
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 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
(OPTION) to the back of the TV, and use commercially available
cord to fix the TV to rigid components such as walls and columns.
1.2.4 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
Ventilation hole
150 mm
200 mm
150 mm
200 mm
50 mm
The hook for fall
prevention(option)
Hook
Wall
It fixes in a band.
TV Stand
*Diagram differs from actual appearance.

(No.YA179)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 color.
(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 color.
(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).