LG L23W36 Service Manual

SERVICE MANUAL

Product Type: LCD TV
Chassis: ML-027C
Manual Part #: 3828VD0140J
Model Line:
Product Year: 2003

L23W36

Model Series:

CONTENTS

Specifications ..............................................................4

Description of Controls .................................................5

Adjustment Instructions ................................................7

Diagrams ...................................................................11

Parts List ...................................................................17

Schematics ....................................................................

Published June 2003

by Technical Publications

Zenith Electronics Corporation

201 James Record Road

Huntsville, Alabama 35824-1513

Copyright © 2003 by Zenith Electronics Corporation

Printed in Korea

- 2 -

PRODUCT SAFETY

IMPORTANT SAFETY NOTICE

This manual was prepared for use only by properly trained audiovisual service
technicians. When servicing this product, under no circumstances should the
original design be modified or altered without permission from Zenith
Electronics Corporation. All components should be replaced only with types
identical to those in the original circuit and their physical location, wiring, and
lead dress must conform to original layout upon completion of repairs. If any
fuse (or Fusible Resistor) in this TV receiver is blown, replace it only with the
factory specified fuse type and rating. When replacing a high wattage resistor
(Oxide Metal Film Resistor, over 1W), keep the resistor 10mm away from PCB.
Always keep wires away from high voltage or high temperature parts.

Special components are also used to prevent shock and fire hazard.
These components are indicated by the letter “x” included in their component
designators and are required to maintain safe performance. No deviations are
allowed without prior approval by Zenith Electronics Corporation. Service work
should be performed only after you are thoroughly familiar with these safety
checks and servicing guidelines.

Circuit diagrams may occasionally differ from the actual circuit used.
This way, implementation of the latest safety and performance improvement
changes into the set is not delayed until the new service literature is printed.

CAUTION: Do not attempt to modify this product in any way.

Never perform customized installations without manufacturer’s
approval.
Unauthorized modifications will not only void the warranty, but may
lead to property damage or user injury.

GENERAL GUIDANCE

An lsolation Transformer should always be used during the servicing
of a receiver whose chassis is not isolated from the AC power line. Use a
transformer of adequate power rating to protect against personal injury from
electrical shocks. It will also protect the receiver and its components from being
damaged by accidental shorts of the circuitry that may be inadvertently
introduced during the service operation.

Before returning the receiver to the customer, always perform an AC leakage
current check on the exposed metallic parts of the cabinet, such as antennas,
terminals, etc., to be sure the set is safe to operate
without damage of electrical shock.

LEAKAGE CURRENT COLD CHECK
(ANTENNA COLD CHECK)

With the instrument’s AC plug removed from AC source, connect an electrical
jumper across the two AC plug prongs. Place the AC 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 1MΩ and 5.2MΩ. When
the exposed metal has no return path to the chassis the reading must be
infinite. Any other abnormality that exists must be corrected before
the receiver is returned to the customer.

ELECTROSTATICALLY SENSITIVE DEVICES

Some semiconductor (solid-state) devices can be damaged easily by static
electricity. Such components commonly are called Electrostatically Sensitive
(ES) Devices. Examples of typical ES devices are integrated circuits and some
field-effect transistors and semiconductor “chip” components. The following
techniques should be used to help reduce the incidence of component damage
caused by static electricity.

1. Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any electrostatic charge on the
body by touching a known earth ground. Alternatively, obtain and wear a
commercially available discharging wrist strap device, which should be
removed for potential shock reasons prior to applying power to the unit under
test.

2. After removing an electrical assembly equipped with ES devices, place the
assembly on a conductive surface such as an ESD mat, to prevent
electrostatic charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.

4. Use only an anti-static solder removal device. Some solder removal devices
not classified as “anti-static” can generate electrical charges sufficient to
damage ES devices.

5. Do not use freon-propelled chemicals. These can generate electrical charge
sufficient to damage ES devices.

6. Do not remove a replacement ES device from its protective package until
immediately before you are ready to install it. (Most replacement ES devices
are packaged with leads electrically shorted together by conductive foam,
aluminum foil, or comparable conductive material.)

7. Immediately before removing the protective material from the leads of a
replacement ES device, touch the protective material to the chassis or circuit
assembly into which the device will be installed.

Caution: Be sure no power is applied to the chassis or circuit, and observe

all other safety precautions.

8. Minimize bodily motions when handling unpackaged replacement ES
devices. (Otherwise, seemingly harmless motion, such as the brushing
together of your clothing or the lifting of your foot from a carpeted floor, can
generate static electricity sufficient to damage an ES device.)

REGULATORY INFORMATION

This equipment has been tested and found to comply with the limits for a Class
B digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction manual, may cause
harmful interference to radio communications. However, there is no guarantee
that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try
to correct the interference by one or more of the following measures: Reorient
or relocate the receiving antenna; Increase the separation between the
equipment and receiver; Connect the equipment into an outlet on a circuit
different from that to which the receiver is connected; Consult the dealer or an
experienced radio/TV technician for help.

The responsible party for this device’s compliance is:

Zenith Electronics Corporation
201 James Record Road
Huntsville, AL 35824, USA
Digital TV Hotline: [phone]

- 3 -

SPECIFICATIONS.................................................................4

DESCRIPTION OF CONTROLS...........................................5

ADJUSTMENT INSTRUCTIONS ..........................................7

TROUBLESHOOTING ........................................................10

PRINTED CIRCUIT BOARD ...............................................11

BLOCK DIAGRAM...............................................................15

EXPLODED VIEW...............................................................16

EXPLODED VIEW PARTS LIST.........................................17

REPLACEMENT PARTS LIST............................................18

SCHEMATIC DIAGRAM..........................................................

TABLE OF CONTENTS

- 4 -

SPECIFICATIONS

MODEL

Width (inches)

Height (inches)

Depth (inches)

Weight (pounds)

Power Requirement

Television System

Television Channel

Television Screen

Power Consumption

External Antenna Impedance

Audio Output

L23W36

23.6

20.6

8.1
22

AC100-240V ~ 60Hz

NTSC

VHF : 2 ~ 13, UHF : 14 ~ 69, Cable : 01 ~ 125

LCD Panel

See the back of the set

75 Ω

7 W + 7 W

- 5 -

DESCRIPTION OF CONTROLS

Controls & Connection Options

Controls & Connection Options

ANT IN

+75 Ω

COMPONENT(480i/480p/720p/1080i)

PC

SOUND

VIDEO IN

DVD/DTV IN

AUDIO

VIDEO

P

R

P

B

Y

AUDIO(MONO)

LR

L

R

PC INPUT

AC INPUT

S-VIDEO VIDEO

AUDIO

R

IN2

L / MONO

MONO DPM

SAP

STEREO

ST

Remote Control Sensor

DPM Indicator

SAP Indicator

Mono Indicator

Power/Standby Indicator

Glows red in Standby mode,
Glows green when the TV is turned on.

Stereo Indicator

Headphone Jack
S-Video Input

Video Input
Audio Input

AC Input

DVD/DTV Input

(Component (480i/480p/720p/1080p), Audio)

Audio / Video Input

PC Sound Input

PC Input

Antenna Input

Channel Buttons

Volume Buttons

ch

vol

menu

enter

on/off

tv

video

/ I

Enter Button

Menu Button

TV·Video Button

On/Off Button

* Kensington Security

System Connector

- 6 -

- When using the remote control, aim it at the remote control sensor on the TV.

powermute

tv/video

multimedia

mts

fcr

ch

ch

vol

enter

1 2 3

4 5 6

7 8 9

0

vol

exit

menu

audio

piparc cc

video

pip input flashbkposition

pip swap sleepsize

still

scan

ch

MUTE

Switches the sound on or off.

PIP

POSITION

PIP INPUT

SIZE

PIP SWAP

STILL
SCAN

CH (

DD/ EE

)

ENTER

CH

DD / EE

(Channel button)

VOL

FF / GG

(Volume button)

POWER

MTS

EXIT

MENU

MULTIMEDIA

Selects:

TV, Component, or RGB-

PC

mode.

VIDEO

CC

FLASHBK

Press the FLASHBK button to
return to the last channel you were
watching.

SLEEP

AUDIO

ARC

TV/VIDEO

Selects: TV, Video 1, Video 2, S-

Video

, Component, or RGB-PC

mode.

FCR

NUMBER buttons

Remote Control Key Functions

Remote Control Key Functions

DESCRIPTION OF CONTROLS

- 7 -

1. Application Object

This instruction is for the application to the LCD TV.

2. Notes

(1) This set uses an adapter, so connect the adapter and the

set correctly before adjustment.
(2) Adjustments must be performed in the correct sequence.
(3) Adjustments must be performed in an enviorment of

25

!5cC (68-85 degrees F) of temperature and 65!10% of

relative humidity.
(4) The input voltage of the receiver must keep 100~240V,

50/60Hz in adjusting.
(5) The set must be operated for 15 minutes prior to adjustment.

[ ‘Heat Run’ must be performed with the full white signal or TV

noise signal.

3. PC Input Mode Adjustment

3-1. Required Test Equipment

(1) A pattern generator; Gray pattern of 16 tones with angle

outline in the quadrilateral (MSPG-925LTH)
(2) An adjustment Remote.

3-2. Preparation for Adjustment

(1) Perform ‘Heat Run’ for more than 15 minutes in white

pattern.
(2) Connect the signal of pattern generator with LCD TV.

3-3. Auto Gray Adjustment

(1) Apply the gray signal XGA(1024X768) 16 tones from a

signal generatror.
(2) In Service menu mode, adjust the Auto gray from 0 to 1 by

using Vol(+) button.

ADJUSTMENT INSTRUCTIONS

- 8 -

ADJUSTMENT INSTRUCTIONS

4. Position Adjustment

Mode
H_Display
V_Display

V_Frequency

H_Total

H_Blanking

H_Sync

H_Polarity

H_Vp

H_Fp

H-Freq[KHz]

/Clk[MHz]

V_Total

V_Blanking

V_Sync

V_Polarity

V_Bp

V_Fp

VGA-60

640
480

60
800
160

96

NEG.

48

16

31.469

25.175
525

45

2

NEG

33
10

VGA-67

640
480

67
864
224

64

NEG.

96

64

35.0

30.24
525

45

3

NEG

39

3

VGA-75

640
480

75
840
200

64

NEG

120

16

37.5

31.5
500

20

3

NEG

16

1

VGA-85

640
480

82
832
192

56

NEG

80

56

43.269

36.0
509

29

3

NEG

25

1

SVGA-56

800
600

56

1024

224

72

POS

128

24

35.156

36.0

62.5
25

2

POS

22

1

SVGA-60

800
600

60

1056

256
128

POS

88
40

37.879

40.0
628

28

4

POS

23

1

SVGA-72

800
600

72

1040

240
120

POS

64
56

48.077

50.0
666

66

6

POS

23
37

Mode
H_Display
V_Display

V_Frequency

H_Total

H_Blanking

H_Sync

H_Polarity

H_Vp

H_Fp

H-Freq[KHz]

/Clk[MHz]

V_Total

V_Blanking

V_Sync

V_Polarity

V_Bp

V_Fp

SVGA-75

800
600

75

1056

256

80

POS

160

16

46.875

49.5
625

25

3

POS

21

1

SVGA-

85800

600

85

1048

248

64

POS

152

32

53.674

56.25
631

31

3

POS

27

1

XGA-60

1024

768

60

1344

320
136

NEG

136
160

48.363

65.0
806

38

6

NEG

29

3

XGA-70

1024

768

70

1328

304
136

NEG

144

24

56.476

75.0
806

38

6

NEG

29

3

XGA-75

1024

768

75

1312

288

96

POS

176

16

60.023

78.75
800

32

3

POS

28

1

XGA-85

1024

768

82

1376

352

96

POS

208

48

68.677

84.997
808

40

3

POS

36

1

WXGA-50

1280

768

50

1648

368
128

NEG

184

56

39.518

65.125
791

23

7

POS

15

1

WXGA-60

1280

768

60

1680

400
136

NEG

200

64

47.693

80.125
795

27

7

POS

19

1