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LG_DU-30LZ30_[SM]


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                                                  website:http://biz.LGservice.com
                                  e-mail:http://www.LGEservice.com/techsup.html




LCD TV
SERVICE MANUAL
CHASSIS : AL-03HA

MODEL : DU-30LZ30
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
                                          CONTENTS




CONTENTS .............................................................................................. 2

PRODUCT SAFETY ..................................................................................3

SPECIFICATION ........................................................................................6

TIMING CHART .........................................................................................9

ADJUSTMENT INSTRUCTION ...............................................................10

SVC REMOCON ......................................................................................13

TROUBLE SHOOTING ............................................................................14

BLOCK DIAGRAM...................................................................................17

WIRING DIAGRAM ..................................................................................19

EXPLODED VIEW .................................................................................. 21

EXPLODED VIEW PARTS LIST ..............................................................22

REPLACEMENT PARTS LIST ............................................................... 23

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
 X-RADIATION, Shock, Fire, or other Hazards.
 Do not modify the original design without permission of manufacturer.


General Guidance                                                      Before returning the receiver to the customer,

An isolation Transformer should always be used during the             always perform an AC leakage current check on the exposed
servicing of a receiver whose chassis is not isolated from the AC     metallic parts of the cabinet, such as antennas, terminals, etc., to
power line. Use a transformer of adequate power rating as this        be sure the set is safe to operate without damage of electrical
protects the technician from accidents resulting in personal injury   shock.
from electrical shocks.
                                                                      Leakage Current Cold Check(Antenna Cold Check)
It will also protect the receiver and it's components from being      With the instrument AC plug removed from AC source, connect an
damaged by accidental shorts of the circuitry that may be             electrical jumper across the two AC plug prongs. Place the AC
inadvertently introduced during the service operation.                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
If any fuse (or Fusible Resistor) in this TV receiver is blown,       each exposed metallic parts such as antenna terminals, phone
replace it with the specified.                                        jacks, etc.
                                                                      If the exposed metallic part has a return path to the chassis, the
When replacing a high wattage resistor (Oxide Metal Film Resistor,    measured resistance should be between 1M and 5.2M.
over 1W), keep the resistor 10mm away from PCB.                       When the exposed metal has no return path to the chassis the
                                                                      reading must be infinite.
Keep wires away from high voltage or high temperature parts.          An other abnormality exists that must be corrected before the
                                                                      receiver is returned to the customer.
Due to high vacuum and large surface area of picture tube,
extreme care should be used in handling the Picture Tube. Do          Leakage Current Hot Check (See below Figure)
not lift the Picture tube by it's Neck.                               Plug the AC cord directly into the AC outlet.
                                                                      Do not use a line Isolation Transformer during this check.
X-RAY Radiation                                                       Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
                                                                      between a known good earth ground (Water Pipe, Conduit, etc.)
Warning:                                                              and the exposed metallic parts.
                                                                      Measure the AC voltage across the resistor using AC voltmeter
                                                                      with 1000 ohms/volt or more sensitivity.
 The source of X-RAY RADIATION in this TV receiver is the High        Reverse plug the AC cord into the AC outlet and repeat AC voltage
 Voltage Section and the Picture Tube.                                measurements for each exposed metallic part. Any voltage
 For continued X-RAY RADIATION protection, the replacement            measured must not exceed 0.75 volt RMS which is corresponds to
 tube must be the same type tube as specified in the                  0.5mA.
 Replacement Parts List.                                              In case any measurement is out of the limits specified, there is
                                                                      possibility of shock hazard and the set must be checked and
To determine the presence of high voltage, use an accurate high       repaired before it is returned to the customer.
impedance HV meter.
                                                                      Leakage Current Hot Check circuit
Adjust brightness, color, contrast controls to minimum.
Measure the high voltage.
The meter reading should indicate                                                           AC Volt-meter
23.5    1.5KV: 14-19 inch, 26      1.5KV: 19-21 inch,
29.0    1.5KV: 25-29 inch, 30.0      1.5KV: 32 inch
If the meter indication is out of tolerance, immediate service and
correction is required to prevent the possibility of premature
                                                                                                                Good Earth Ground
component failure.
                                                                                                                such as WATER PIPE,
                                                                      To Instrument's                           CONDUIT etc.
                                                                                                 0.15uF
                                                                      exposed
                                                                      METALLIC PARTS


                                                                                              1.5 Kohm/10W
                                          SERVICING PRECAUTIONS
CAUTION: Before servicing receivers covered by this service             should be used to help reduce the incidence of component
manual and its supplements and addenda, read and follow the             damage caused by static by static electricity.
SAFETY PRECAUTIONS on page 3 of this publication.                       1. Immediately before handling any semiconductor component or
NOTE: If unforeseen circumstances create conflict between the              semiconductor-equipped assembly, drain off any electrostatic
following servicing precautions and any of the safety precautions on       charge on your body by touching a known earth ground.
page 3 of this publication, always follow the safety precautions.          Alternatively, obtain and wear a commercially available
Remember: Safety First.                                                    discharging wrist strap device, which should be removed to
                                                                           prevent potential shock reasons prior to applying power to the
General Servicing Precautions                                              unit under test.
1. Always unplug the receiver AC power cord from the AC power           2. After removing an electrical assembly equipped with ES
   source before;                                                          devices, place the assembly on a conductive surface such as
   a. Removing or reinstalling any component, circuit board                aluminum foil, to prevent electrostatic charge buildup or
      module or any other receiver assembly.                               exposure of the assembly.
   b. Disconnecting or reconnecting any receiver electrical plug or     3. Use only a grounded-tip soldering iron to solder or unsolder ES
      other electrical connection.                                         devices.
   c. Connecting a test substitute in parallel with an electrolytic     4. Use only an anti-static type solder removal device. Some solder
      capacitor in the receiver.                                           removal devices not classified as "anti-static" can generate
      CAUTION: A wrong part substitution or incorrect polarity             electrical charges sufficient to damage ES devices.
      installation of electrolytic capacitors may result in an          5. Do not use freon-propelled chemicals. These can generate
      explosion hazard.                                                    electrical charges sufficient to damage ES devices.
   d. Discharging the picture tube anode.                               6. Do not remove a replacement ES device from its protective
2. Test high voltage only by measuring it with an appropriate high         package until immediately before you are ready to install it.
   voltage meter or other voltage measuring device (DVM,                   (Most replacement ES devices are packaged with leads
   FETVOM, etc) equipped with a suitable high voltage probe.               electrically shorted together by conductive foam, aluminum foil
   Do not test high voltage by "drawing an arc".                           or comparable conductive material).
3. Discharge the picture tube anode only by (a) first connecting        7. Immediately before removing the protective material from the
   one end of an insulated clip lead to the degaussing or kine             leads of a replacement ES device, touch the protective material
   aquadag grounding system shield at the point where the picture          to the chassis or circuit assembly into which the device will be
   tube socket ground lead is connected, and then (b) touch the            installed.
   other end of the insulated clip lead to the picture tube anode          CAUTION: Be sure no power is applied to the chassis or circuit,
   button, using an insulating handle to avoid personal contact with       and observe all other safety precautions.
   high voltage.                                                        8. Minimize bodily motions when handling unpackaged
4. Do not spray chemicals on or near this receiver or any of its           replacement ES devices. (Otherwise harmless motion such as
   assemblies.                                                             the brushing together of your clothes fabric or the lifting of your
5. Unless specified otherwise in this service manual, clean                foot from a carpeted floor can generate static electricity
   electrical contacts only by applying the following mixture to the       sufficient to damage an ES device.)
   contacts with a pipe cleaner, cotton-tipped stick or comparable
   non-abrasive applicator; 10% (by volume) Acetone and 90% (by         General Soldering Guidelines
   volume) isopropyl alcohol (90%-99% strength)                         1. Use a grounded-tip, low-wattage soldering iron and appropriate
   CAUTION: This is a flammable mixture.                                   tip size and shape that will maintain tip temperature within the
   Unless specified otherwise in this service manual, lubrication of       range or 500 F to 600 F.
   contacts in not required.                                            2. Use an appropriate gauge of RMA resin-core solder composed
6. Do not defeat any plug/socket B+ voltage interlocks with which          of 60 parts tin/40 parts lead.
   receivers covered by this service manual might be equipped.          3. Keep the soldering iron tip clean and well tinned.
7. Do not apply AC power to this instrument and/or any of its           4. Thoroughly clean the surfaces to be soldered. Use a mall wire-
   electrical assemblies unless all solid-state device heat sinks are      bristle (0.5 inch, or 1.25cm) brush with a metal handle.
   correctly installed.                                                    Do not use freon-propelled spray-on cleaners.
8. Always connect the test receiver ground lead to the receiver         5. Use the following unsoldering technique
   chassis ground before connecting the test receiver positive             a. Allow the soldering iron tip to reach normal temperature.
   lead.                                                                       (500 F to 600 F)
   Always remove the test receiver ground lead last.                       b. Heat the component lead until the solder melts.
9. Use with this receiver only the test fixtures specified in this         c. Quickly draw the melted solder with an anti-static, suction-
   service manual.                                                             type solder removal device or with solder braid.
   CAUTION: Do not connect the test fixture ground strap to any                CAUTION: Work quickly to avoid overheating the
   heat sink in this receiver.                                                 circuitboard printed foil.
                                                                        6. Use the following soldering technique.
Electrostatically Sensitive (ES) Devices                                   a. Allow the soldering iron tip to reach a normal temperature
Some semiconductor (solid-state) devices can be damaged easily                 (500 F to 600 F)
by static electricity. Such components commonly are called                 b. First, hold the soldering iron tip and solder the strand against
Electrostatically Sensitive (ES) Devices. Examples of typical ES               the component lead until the solder melts.
devices are integrated circuits and some field-effect transistors and
semiconductor "chip" components. The following techniques



                                                                    -4-
   c.  Quickly move the soldering iron tip to the junction of the        Fuse and Conventional Resistor
      component lead and the printed circuit foil, and hold it there     Removal/Replacement
      only until the solder flows onto and around both the               1. Clip each fuse or resistor lead at top of the circuit board hollow
      component lead and the foil.                                          stake.
      CAUTION: Work quickly to avoid overheating the circuit             2. Securely crimp the leads of replacement component around
      board printed foil.                                                   notch at stake top.
   d. Closely inspect the solder area and remove any excess or           3. Solder the connections.
      splashed solder with a small wire-bristle brush.                      CAUTION: Maintain original spacing between the replaced
                                                                            component and adjacent components and the circuit board to
IC Remove/Replacement                                                       prevent excessive component temperatures.
Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent flat against the           Circuit Board Foil Repair
circuit foil. When holes are the slotted type, the following technique   Excessive heat applied to the copper foil of any printed circuit
should be used to remove and replace the IC. When working with           board will weaken the adhesive that bonds the foil to the circuit
boards using the familiar round hole, use the standard technique         board causing the foil to separate from or "lift-off" the board. The
as outlined in paragraphs 5 and 6 above.                                 following guidelines and procedures should be followed whenever
                                                                         this condition is encountered.
Removal
1. Desolder and straighten each IC lead in one operation by gently       At IC Connections
   prying up on the lead with the soldering iron tip as the solder       To repair a defective copper pattern at IC connections use the
   melts.                                                                following procedure to install a jumper wire on the copper pattern
2. Draw away the melted solder with an anti-static suction-type          side of the circuit board. (Use this technique only on IC
   solder removal device (or with solder braid) before removing the      connections).
   IC.
Replacement                                                              1. Carefully remove the damaged copper pattern with a sharp
1. Carefully insert the replacement IC in the circuit board.                knife. (Remove only as much copper as absolutely necessary).
2. Carefully bend each IC lead against the circuit foil pad and          2. carefully scratch away the solder resist and acrylic coating (if
   solder it.                                                               used) from the end of the remaining copper pattern.
3. Clean the soldered areas with a small wire-bristle brush.             3. Bend a small "U" in one end of a small gauge jumper wire and
   (It is not necessary to reapply acrylic coating to the areas).           carefully crimp it around the IC pin. Solder the IC connection.
                                                                         4. Route the jumper wire along the path of the out-away copper
"Small-Signal" Discrete Transistor                                          pattern and let it overlap the previously scraped end of the good
Removal/Replacement                                                         copper pattern. Solder the overlapped area and clip off any
1. Remove the defective transistor by clipping its leads as close as        excess jumper wire.
   possible to the component body.
2. Bend into a "U" shape the end of each of three leads remaining        At Other Connections
   on the circuit board.                                                 Use the following technique to repair the defective copper pattern
3. Bend into a "U" shape the replacement transistor leads.               at connections other than IC Pins. This technique involves the
4. Connect the replacement transistor leads to the corresponding         installation of a jumper wire on the component side of the circuit
   leads extending from the circuit board and crimp the "U" with         board.
   long nose pliers to insure metal to metal contact then solder
   each connection.                                                      1. Remove the defective copper pattern with a sharp knife.
                                                                            Remove at least 1/4 inch of copper, to ensure that a hazardous
Power Output, Transistor Device                                             condition will not exist if the jumper wire opens.
Removal/Replacement                                                      2. Trace along the copper pattern from both sides of the pattern
1. Heat and remove all solder from around the transistor leads.             break and locate the nearest component that is directly
2. Remove the heat sink mounting screw (if so equipped).                    connected to the affected copper pattern.
3. Carefully remove the transistor from the heat sink of the circuit     3. Connect insulated 20-gauge jumper wire from the lead of the
   board.                                                                   nearest component on one side of the pattern break to the lead
4. Insert new transistor in the circuit board.                              of the nearest component on the other side.
5. Solder each transistor lead, and clip off excess lead.                   Carefully crimp and solder the connections.
6. Replace heat sink.                                                       CAUTION: Be sure the insulated jumper wire is dressed so the
                                                                            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.


                                                                     -5-
                                                    SPECIFICATION
NOTE : Specifications and others are subject to change without notice for improvement.

1. Application range                                                    3. Test and Inspection method
This specification is applied to ML-027C chassis.                          (1) Capacity: Follow LG electronics TV Testing Standard.
                                                                           (2) Another Required Standard
2. Requirement for Test                                                    EMI: Following CE Standard(EN55020,EN55013)
Testing for standard of each part must be followed in below                SAFETY: Following CB Standard(EN60065)
condition.

    (1) Temperature: 25



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