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LCD TV
SERVICE MANUAL
CHASSIS : ML-041D
MODEL : 23LX1RV-MC
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
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DVD / CD PLAYER
CONTENTS
CONTENTS .............................................................................................. 2
PRODUCT SAFETY ..................................................................................3
SPECIFICATION ........................................................................................6
ADJUSTMENT INSTRUCTION ...............................................................10
TROUBLE SHOOTING ............................................................................13
BLOCK DIAGRAM...................................................................................19
WIRING DIAGRAM ..................................................................................21
EXPLODED VIEW .................................................................................. 22
EXPLODED VIEW PARTS LIST ..............................................................23
REPLACEMENT PARTS LIST ............................................................... 24
SVC. SHEET ...............................................................................................
-2-
SAFETY PRECAUTIONS
IMPORTANT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the
Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance Leakage Current Hot Check (See below Figure)
Plug the AC cord directly into the AC outlet.
An isolation Transformer should always be used during the Do not use a line Isolation Transformer during this check.
servicing of a receiver whose chassis is not isolated from the AC Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
power line. Use a transformer of adequate power rating as this between a known good earth ground (Water Pipe, Conduit, etc.)
protects the technician from accidents resulting in personal injury and the exposed metallic parts.
from electrical shocks. Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or more sensitivity.
It will also protect the receiver and it's components from being Reverse plug the AC cord into the AC outlet and repeat AC voltage
damaged by accidental shorts of the circuitry that may be measurements for each exposed metallic part. Any voltage
inadvertently introduced during the service operation. measured must not exceed 0.75 volt RMS which is corresponds to
0.5mA.
If any fuse (or Fusible Resistor) in this TV receiver is blown, In case any measurement is out of the limits specified, there is
replace it with the specified. possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1W), keep the resistor 10mm away from PCB. Leakage Current Hot Check circuit
Keep wires away from high voltage or high temperature parts. AC Volt-meter
Before returning the receiver to the customer,
always perform an AC leakage current check on the exposed
Good Earth Ground
metallic parts of the cabinet, such as antennas, terminals, etc., to such as WATER PIPE,
be sure the set is safe to operate without damage of electrical CONDUIT etc.
To Instrument's 0.15uF
shock. exposed
METALLIC PARTS
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC 1.5 Kohm/10W
switch in the on position, connect one lead of ohm-meter to the AC
plug prongs tied together and touch other ohm-meter lead in turn to
each exposed metallic parts such as antenna terminals, phone
jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1M and 5.2M.
When the exposed metal has no return path to the chassis the
reading must be infinite.
An other abnormality exists that must be corrected before the
receiver is returned to the customer.
-3-
SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service 2. After removing an electrical assembly equipped with ES
manual and its supplements and addenda, read and follow the devices, place the assembly on a conductive surface such as
SAFETY PRECAUTIONS on page 3 of this publication. aluminum foil, to prevent electrostatic charge buildup or
NOTE: If unforeseen circumstances create conflict between the exposure of the assembly.
following servicing precautions and any of the safety precautions on 3. Use only a grounded-tip soldering iron to solder or unsolder ES
page 3 of this publication, always follow the safety precautions. devices.
Remember: Safety First. 4. Use only an anti-static type solder removal device. Some solder
removal devices not classified as "anti-static" can generate
General Servicing Precautions electrical charges sufficient to damage ES devices.
1. Always unplug the receiver AC power cord from the AC power 5. Do not use freon-propelled chemicals. These can generate
source before; electrical charges sufficient to damage ES devices.
a. Removing or reinstalling any component, circuit board 6. Do not remove a replacement ES device from its protective
module or any other receiver assembly. package until immediately before you are ready to install it.
b. Disconnecting or reconnecting any receiver electrical plug or (Most replacement ES devices are packaged with leads
other electrical connection. electrically shorted together by conductive foam, aluminum foil
c. Connecting a test substitute in parallel with an electrolytic or comparable conductive material).
capacitor in the receiver. 7. Immediately before removing the protective material from the
CAUTION: A wrong part substitution or incorrect polarity leads of a replacement ES device, touch the protective material
installation of electrolytic capacitors may result in an to the chassis or circuit assembly into which the device will be
explosion hazard. installed.
CAUTION: Be sure no power is applied to the chassis or circuit,
2. Test high voltage only by measuring it with an appropriate high and observe all other safety precautions.
voltage meter or other voltage measuring device (DVM, 8. Minimize bodily motions when handling unpackaged
FETVOM, etc) equipped with a suitable high voltage probe. replacement ES devices. (Otherwise harmless motion such as
Do not test high voltage by "drawing an arc". the brushing together of your clothes fabric or the lifting of your
3. Do not spray chemicals on or near this receiver or any of its foot from a carpeted floor can generate static electricity
assemblies. sufficient to damage an ES device.)
4. Unless specified otherwise in this service manual, clean
electrical contacts only by applying the following mixture to the General Soldering Guidelines
contacts with a pipe cleaner, cotton-tipped stick or comparable 1. Use a grounded-tip, low-wattage soldering iron and appropriate
non-abrasive applicator; 10% (by volume) Acetone and 90% (by tip size and shape that will maintain tip temperature within the
volume) isopropyl alcohol (90%-99% strength) range or 500 F to 600 F.
CAUTION: This is a flammable mixture. 2. Use an appropriate gauge of RMA resin-core solder composed
Unless specified otherwise in this service manual, lubrication of of 60 parts tin/40 parts lead.
contacts in not required. 3. Keep the soldering iron tip clean and well tinned.
5. Do not defeat any plug/socket B+ voltage interlocks with which 4. Thoroughly clean the surfaces to be soldered. Use a mall wire-
receivers covered by this service manual might be equipped. bristle (0.5 inch, or 1.25cm) brush with a metal handle.
6. Do not apply AC power to this instrument and/or any of its Do not use freon-propelled spray-on cleaners.
electrical assemblies unless all solid-state device heat sinks are 5. Use the following unsoldering technique
correctly installed. a. Allow the soldering iron tip to reach normal temperature.
7. Always connect the test receiver ground lead to the receiver (500 F to 600 F)
chassis ground before connecting the test receiver positive b. Heat the component lead until the solder melts.
lead. c. Quickly draw the melted solder with an anti-static, suction-
Always remove the test receiver ground lead last. type solder removal device or with solder braid.
8. Use with this receiver only the test fixtures specified in this CAUTION: Work quickly to avoid overheating the
service manual. circuitboard printed foil.
CAUTION: Do not connect the test fixture ground strap to any 6. Use the following soldering technique.
heat sink in this receiver. a. Allow the soldering iron tip to reach a normal temperature
(500 F to 600 F)
Electrostatically Sensitive (ES) Devices
b. First, hold the soldering iron tip and solder the strand against
Some semiconductor (solid-state) devices can be damaged easily
the component lead until the solder melts.
by static electricity. Such components commonly are called
c. Quickly move the soldering iron tip to the junction of the
Electrostatically Sensitive (ES) Devices. Examples of typical ES
component lead and the printed circuit foil, and hold it there
devices are integrated circuits and some field-effect transistors and
only until the solder flows onto and around both the
semiconductor "chip" components. The following techniques
component lead and the foil.
should be used to help reduce the incidence of component
CAUTION: Work quickly to avoid overheating the circuit
damage caused by static by static electricity.
board printed foil.
1. Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any electrostatic d. Closely inspect the solder area and remove any excess or
charge on your body by touching a known earth ground. splashed solder with a small wire-bristle brush.
Alternatively, obtain and wear a commercially available
discharging wrist strap device, which should be removed to
prevent potential shock reasons prior to applying power to the
unit under test.
-4-
IC Remove/Replacement
Some chassis circuit boards have slotted holes (oblong) through Circuit Board Foil Repair
which the IC leads are inserted and then bent flat against the Excessive heat applied to the copper foil of any printed circuit
circuit foil. When holes are the slotted type, the following technique board will weaken the adhesive that bonds the foil to the circuit
should be used to remove and replace the IC. When working with board causing the foil to separate from or "lift-off" the board. The
boards using the familiar round hole, use the standard technique following guidelines and procedures should be followed whenever
as outlined in paragraphs 5 and 6 above. this condition is encountered.
Removal At IC Connections
1. Desolder and straighten each IC lead in one operation by gently To repair a defective copper pattern at IC connections use the
prying up on the lead with the soldering iron tip as the solder following procedure to install a jumper wire on the copper pattern
melts. side of the circuit board. (Use this technique only on IC
2. Draw away the melted solder with an anti-static suction-type connections).
solder removal device (or with solder braid) before removing the
IC. 1. Carefully remove the damaged copper pattern with a sharp
Replacement knife. (Remove only as much copper as absolutely necessary).
1. Carefully insert the replacement IC in the circuit board. 2. carefully scratch away the solder resist and acrylic coating (if
2. Carefully bend each IC lead against the circuit foil pad and used) from the end of the remaining copper pattern.
solder it. 3. Bend a small "U" in one end of a small gauge jumper wire and
3. Clean the soldered areas with a small wire-bristle brush. carefully crimp it around the IC pin. Solder the IC connection.
(It is not necessary to reapply acrylic coating to the areas). 4. Route the jumper wire along the path of the out-away copper
pattern and let it overlap the previously scraped end of the good
"Small-Signal" Discrete Transistor copper pattern. Solder the overlapped area and clip off any
Removal/Replacement excess jumper wire.
1. Remove the defective transistor by clipping its leads as close as
possible to the component body. At Other Connections
2. Bend into a "U" shape the end of each of three leads remaining Use the following technique to repair the defective copper pattern
on the circuit board. at connections other than IC Pins. This technique involves the
3. Bend into a "U" shape the replacement transistor leads. installation of a jumper wire on the component side of the circuit
4. Connect the replacement transistor leads to the corresponding board.
leads extending from the circuit board and crimp the "U" with
long nose pliers to insure metal to metal contact then solder 1. Remove the defective copper pattern with a sharp knife.
each connection. Remove at least 1/4 inch of copper, to ensure that a hazardous
condition will not exist if the jumper wire opens.
Power Output, Transistor Device 2. Trace along the copper pattern from both sides of the pattern
Removal/Replacement break and locate the nearest component that is directly
1. Heat and remove all solder from around the transistor leads. connected to the affected copper pattern.
2. Remove the heat sink mounting screw (if so equipped). 3. Connect insulated 20-gauge jumper wire from the lead of the
3. Carefully remove the transistor from the heat sink of the circuit nearest component on one side of the pattern break to the lead
board. of the nearest component on the other side.
4. Insert new transistor in the circuit board. Carefully crimp and solder the connections.
5. Solder each transistor lead, and clip off excess lead. CAUTION: Be sure the insulated jumper wire is dressed so the
6. Replace heat sink. it does not touch components or sharp edges.
Diode Removal/Replacement
1. Remove defective diode by clipping its leads as close as
possible to diode body.
2. Bend the two remaining leads perpendicular y to the circuit
board.
3. Observing diode polarity, wrap each lead of the new diode
around the corresponding lead on the circuit board.
4. Securely crimp each connection and solder it.
5. Inspect (on the circuit board copper side) the solder joints of
the two "original" leads. If they are not shiny, reheat them and if
necessary, apply additional solder.
Fuse and Conventional Resistor
Removal/Replacement
1. Clip each fuse or resistor lead at top of the circuit board hollow
stake.
2. Securely crimp the leads of replacement component around
notch at stake top.
3. Solder the connections.
CAUTION: Maintain original spacing between the replaced
component and adjacent components and the circuit board to
prevent excessive component temperatures.
-5-
SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.
1. Application range
This specification is applied to ML-041D chassis.
2. Requirement for Test
Testing for standard of each part must be followed in below
condition.
(1) Temperature: 25