LG 24MB35DM Service Manual

Internal Use Only

North/Latin America http://aic.lgservice.com
Europe/Africa http://eic.lgservice.com
Asia/Oceania http://biz.lgservice.com

COLOR MONITOR

SERVICE MANUAL

CHASSIS NO. : LM14F

MODEL:

CAUTION

BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

P/NO : MFL67715243 (1312-REV00) Print

24MB35DM

ed in China

CONTENTS

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

PRECAUTION............................................................................................3

SERVICING PRECAUTIONS.....................................................................4

SPECIFICATIONS......................................................................................6

TIMING CHART .......................................................................................11

ADJUSTMENT .........................................................................................14

BLOCK DIAGRAM...................................................................................18

TROUBLE SHOOTING ............................................................................19

EXPLODED VIEW .................................................................................. 22

SVC. SHEET ...............................................................................................

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

- 2 -

LGE Internal Use Only

PRECAUTION

WARNING FOR THE SAFETY-RELATED COMPONENT.

• There are some special components used in LCD monitor that

are important for safety. These parts are marked on the
schematic diagram and the Exploded View. It is essential
that these critical parts should be replaced with the
manufacturer’s specified parts to prevent electric shock, fire or
other hazard.

• Do not modify original design without obtaining written
permission from manufacturer or you will void the original parts
and labor guarantee.

TAKE CARE DURING HANDLING THE LCD MODULE WITH
BACKLIGHT UNIT.

• Must mount the module using mounting holes arranged in four
corners.

• Do not press on the panel, edge of the frame strongly or electric
shock as this will result in damage to the screen.

• Do not scratch or press on the panel with any sharp objects,
such as pencil or pen as this may result in damage to the panel.

• Protect the module from the ESD as it may damage the
electronic circuit (C-MOS).

WARNING

BE CAREFUL ELECTRIC SHOCK !

• If you want to replace with the new backlight (CCFL) or LIPS
part, must disconnect the AC power because high voltage
appears at inverter circuit about 650Vrms.

• Handle with care wires or connectors of the inverter circuit. If
the wires are pressed cause short and may burn or take fire.

Leakage Current Hot Check Circuit

AC Volt-meter

Good Earth Ground
such as WATER PIPE,

To Instrument's
exposed
METALLIC PARTS

When 25A is impressed between Earth and 2nd Ground
for 1 second, Resistance must be less than 0.1

*Base on Adjustment standard

0.15uF

1.5 Kohm/10W

CONDUIT etc.

Ω

• Make certain that treatment person’s body are grounded
through wrist band.

• Do not leave the module in high temperature and in areas of
high humidity for a long time.

• The module not be exposed to the direct sunlight.

• Avoid contact with water as it may a short circuit within the
module.

• If the surface of panel become dirty, please wipe it off with a
softmaterial. (Cleaning with a dirty or rough cloth may damage
the panel.)

CAUTION

Please use only a plastic screwdriver to protect yourself
from shock hazard during service operation.

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

- 3 -

LGE Internal Use Only

SERVICING PRECAUTIONS

CAUTION: Before servicing receivers covered by this service

manual and its supplements and addenda, read and follow the

SAFETY PRECAUTIONS on page 3 of this publication.

NOTE: If unforeseen circumstances create conflict between the

following servicing precautions and any of the safety precautions on
page 3 of this publication, always follow the safety precautions.
Remember: Safety First.

General Servicing Precautions

1. Always unplug the receiver AC power cord from the AC power
source before;
a. Removing or reinstalling any component, circuit board

module or any other receiver assembly.

b. Disconnecting or re-connecting any receiver electrical plug or

other electrical connection.

c. Connecting a test substitute in parallel with an electrolytic

capacitor in the receiver.
CAUTION: A wrong part substitution or incorrect polarity
installation of electrolytic capacitors may result in an
explosion hazard.

2. Test high voltage only by measuring it with an appropriate high
voltage meter or other voltage measuring device (DVM,
FETVOM, etc) equipped with a suitable high voltage probe.
Do not test high voltage by "drawing an arc".

3. Do not spray chemicals on or near this receiver or any of its
assemblies.

4. Unless specified otherwise in this service manual, clean
electrical contacts only by applying the following mixture to the
contacts with a pipe cleaner, cotton-tipped stick or comparable
non-abrasive applicator; 10% (by volume) Acetone and 90% (by
volume) is opropyl alcohol (90%-99% strength)
CAUTION: This is a flammable mixture.
Unless specified otherwise in this service manual, lubrication of
contacts in not required.

5. Do not defeat any plug/socket B+ voltage interlocks with which
receivers covered by this service manual might be equipped.

6. Do not apply AC power to this instrument and/or any of its
electrical assemblies unless all solid-state device heat sinks are
correctly installed.

7. Always connect the test receiver ground lead to the receiver
chassis ground before connecting the test receiver positive
lead.
Always remove the test receiver ground lead last.

8. Use with this receiver only the test fixtures specified in this

service manual.

CAUTION: Do not connect the test fixture ground strap to any
heat sink in this receiver.

Electrostatically Sensitive (ES) 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 by static electricity.

1. Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any electrostatic
charge on your body by touching a known earth ground.
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.

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

2. After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such as
aluminum foil, 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 type 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 charges 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 harmless motion such as
the brushing together of your clothes fabric or the lifting of your
foot from a carpeted floor can generate static electricity
sufficient to damage an ES device.)

General Soldering Guidelines

1. Use a grounded-tip, low-wattage soldering iron and appropriate
tip size and shape that will maintain tip temperature within the
range or 500ºF to 600ºF.

2. Use an appropriate gauge of RMA resin-core solder composed
of 60 parts tin/40 parts lead.

3. Keep the soldering iron tip clean and well tinned.

4. Thoroughly clean the surfaces to be soldered. Use a mall wire­bristle (0.5 inch, or 1.25cm) brush with a metal handle.
Do not use freon-propelled spray-on cleaners.

5. Use the following unsoldering technique
a. Allow the soldering iron tip to reach normal temperature.

(500ºF to 600ºF)
b. Heat the component lead until the solder melts.
c. Quickly draw the melted solder with an anti-static, suction-

type solder removal device or with solder braid.

CAUTION: Work quickly to avoid overheating the circuit

board printed foil.

6. Use the following soldering technique.
a. Allow the soldering iron tip to reach a normal temperature

(500ºF to 600ºF)

b. First, hold the soldering iron tip and solder the strand against

the component lead until the solder melts.

c. Quickly move the soldering iron tip to the junction of the

component lead and the printed circuit foil, and hold it there
only until the solder flows onto and around both the
component lead and the foil.
CAUTION: Work quickly to avoid overheating the circuit
board printed foil.

d. Closely inspect the solder area and remove any excess or

splashed solder with a small wire-bristle brush.

- 4 -

LGE Internal Use Only

IC Remove/Replacement

Some chassis circuit boards have slotted holes (oblong) through
which the IC leads are inserted and then bent flat against the
circuit foil. When holes are the slotted type, the following technique
should be used to remove and replace the IC. When working with
boards using the familiar round hole, use the standard technique
as outlined in paragraphs 5 and 6 above.

Removal

1. Desolder and straighten each IC lead in one operation by gently
prying up on the lead with the soldering iron tip as the solder
melts.

2. Draw away the melted solder with an anti-static suction-type
solder removal device (or with solder braid) before removing the
IC.

Replacement

1. Carefully insert the replacement IC in the circuit board.

2. Carefully bend each IC lead against the circuit foil pad and
solder it.

3. Clean the soldered areas with a small wire-bristle brush.
(It is not necessary to reapply acrylic coating to the areas).

"Small-Signal" Discrete TransistorRemoval/Replacement

1. Remove the defective transistor by clipping its leads as close as
possible to the component body.

2. Bend into a "U" shape the end of each of three leads remaining
on the circuit board.

3. Bend into a "U" shape the replacement transistor leads.

4. Connect the replacement transistor leads to the corresponding
leads extending from the circuit board and crimp the "U" with
long nose pliers to insure metal to metal contact then solder
each connection.

Power Output, Transistor Device
Removal/Replacement

1. Heat and remove all solder from around the transistor leads.

2. Remove the heat sink mounting screw (if so equipped).

3. Carefully remove the transistor from the heat sink of the circuit
board.

4. Insert new transistor in the circuit board.

5. Solder each transistor lead, and clip off excess lead.

6. Replace heat sink.

Circuit Board Foil Repair

Excessive heat applied to the copper foil of any printed circuit
board will weaken the adhesive that bonds the foil to the circuit
board causing the foil to separate from or "lift-off" the board. The
following guidelines and procedures should be followed whenever
this condition is encountered.

At IC Connections

To repair a defective copper pattern at IC connections use the
following procedure to install a jumper wire on the copper pattern
side of the circuit board. (Use this technique only on IC
connections).

1. Carefully remove the damaged copper pattern with a sharp
knife. (Remove only as much copper as absolutely necessary).

2. carefully scratch away the solder resist and acrylic coating (if
used) from the end of the remaining copper pattern.

3. Bend a small "U" in one end of a small gauge jumper wire and
carefully crimp it around the IC pin. Solder the IC connection.

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
copper pattern. Solder the overlapped area and clip off any
excess jumper wire.

At Other Connections

Use the following technique to repair the defective copper pattern
at connections other than IC Pins. This technique involves the
installation of a jumper wire on the component side of the circuit
board.

1. Remove the defective copper pattern with a sharp knife.
Remove at least 1/4 inch of copper, to ensure that a hazardous
condition will not exist if the jumper wire opens.

2. Trace along the copper pattern from both sides of the pattern
break and locate the nearest component that is directly
connected to the affected copper pattern.

3. Connect insulated 20-gauge jumper wire from the lead of the
nearest component on one side of the pattern break to the lead
of the nearest component on the other side.
Carefully crimp and solder the connections.
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.

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.

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

- 5 -

LGE Internal Use Only

1. General Specification

SPECIFICATIONS

No Item

1 Customer
2 User Model Name
3 Sale region
4 Feature 23.8” Wide L
5 Chassis Nam

General
Scope

6

7

8 Cable

Power Cord

Signal Cable

e LM14F

External SW

&Adj.

Function

(D

-SUB)

DVI

BRAND
24MB35DM
Refer to Suffix standard

Menu, reader

OSD, Control lock, 1 Analog/1 DVI/1 Audio Input, HDCP,
, Super Energy Saving, Picture Mode, Six Color, Factory
Gamma Calibration

Length : 1.87
Shape : Wall-out
Color : Black

Length : 1.8m
Shape : Detachable Type
Color : Black
Pin : Triple Row, 15 Pin D-Sub

Length : 2.0m
Shape : Detacha
Color : Black
Pin : Triple Row, 18-Position DVI-D

Content

CD MONITOR

, SES, auto, input, power

M

ble Type

Remark

Refer to Suffix

standard and power

cord table

Refer to Suffix

standard

Refer to Suffix

standard

Audio

TV Length : ,Shape

9

LIPS Input:

10

Applying mod

le list

u

Length : 1.5M

lor: Black ,

Co
Pin：2P

AC100

P/No Specification

EAJ62509701

: ,Color: ,Pin Do not Support

0V 50~60Hz,1.2A Max

~24

(IPS) LM238WF1-SLE1

Do not Support

Refer to Suffix

standard

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

- 6 -

LGE Internal Use Only

2. Mechanical specification

No Item Content Remark

1

Product

Dimensi

Before Packing

on

After Packing 62.6 41.3

2

3

Product

Wei

ght

Container

Loadi

Quantity

4 Stand

A

ssy

ng

Only SET 3.9 Unit: kg

With BOX 5.5 Unit: kg

Individual or
Palletizing

Type Atta chable

Size (W x D x H) 24.95X4.1X21 Unit: cm

Tilt Degree

Tilt forc

e 1~3kgf

Pivot degree

5

** C/A

Appea

ran

+ B/C GAP: 0.5mm (Design gap)

c

e General Refer to Standard of LG(56)G2-1011

Width (W) Length (D) Height (H)

56.9 43.3 21 with Stand (cm)

56.9 34.2 6.3

Without Stand (cm)

20.2 Unit: cm

20ft 40ft

Indi. Wooden

561 400 1

-5（±5） ~ 20（±5）

Indi. Wooden

166/1378 880/868

Unit : degree

No

Unit : degree

3. Optical Character

No Item Criteria Remark

1

2

Viewing Angl
<CR≥10>

Luminance(휘도)

3

Contrast Ratio(명암 비

4 Response T

5 Read

6 EPA Con

e

ime

er mode

sumption

Horizontal(R/L) : 178º (Typ.)

op/

Vertical(T

verage Luminance

A
(cd/m

Average
(cd/m

Average Lum
(cd/m

Super Energy Savi
ng

Luminance

rmity

Unifo

)

600(MIN), 1000(TYP), DFC->5,000,000:1(Typ.)

Bottom) : 178º (Typ.)

2

)

Lum

2

)

inance

inance

2

)

200(min), 250 (T

yp.)

(Full white pattern, 0.7V)

150 (min)

(Full white pa

ttern, 0.7V)

150(min)

(Full white pa

SES savi

SES saving (high): 4w/h SES HIGH(20% - 30%)

ttern, 0.7V)

ng (low): 2w/h SES LOW(10% - 20%)

75%(min),

23MB35: Gray to Gray: 5.5ms (high), 8ms(middle), 10ms(low)

24MB35: Gray to Gray: 6 ms (high), 8ms(middle), 10ms(low)

Reader1: x（0.335 – 0.395）, y (0.330 – 0.390)
Reader2: x（0.323 – 0.383）, y (0.337 – 0.397)

23MB35PM < 21 Wh

24MB35DM < 23 Wh

Warm
(6500K)

ness:100

Bright
Contrast:100

Medium
(8000K)

Cool
(9300K)

Change the ce
nter luminance

cd/m2

to 200

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

- 7 -

LGE Internal Use Only

4. Engineering Specification

1

2
3

4

Supported Sync.

Operating Frequenc

Resolution

Input Voltage Voltage

Type

y

5 Inrush Current Co
6

Op

erating

Cond

itio

n

On Mode

Sleep Mode

Off Mode

r switch off)

(Powe

7

Super Energys S

8
9

EP A6.0

MTBF

10

Using Altitude

aving Low/High/Off low white

11

Environm

0perating

ent

Conditi

on

Storag

e

Separate Sync., Digital

Analog/
Digital

Analog/
Digital

Horizontal 30 ~ 83kHz

Vertical

Max.

Recommend

56~ 75

Hz
1920×1080 @ 60Hz
1920×1080 @

:100 – 240 Vac, 50- 60HZ

60Hz

ld Start : 50 A Hot : 120 A

Sync

(H/V)

On/

On Active

On/On (Sup

er

Energy saving

off)

Off/On
On/Off

Off/Off

Video LED Wattage

Active

Off

white

ter

(Af

about 15s ,

white

white

ng

turn to Off)

ter about

(Af
15s , turn to
Off)

Blinki

23MB35PM:29

yp.)

W(T

24MB35DM:31

W(Typ.)

22MB35DM:24

W(Typ.)

23MB35PM

(max)

33W

24MB35DM:36

W(max.)

22MB35DM:28

W(max.)

0.3W under

Test condition

1.1920x1080@
60Hz

2. burst pattern

3. 100~240V

4. After aging
30mi

- - Off 0.3W under

22/23/24

Typ:(

Brightness:changed(to 200nits) contrast:100

Worst:(Brightness:100 contrast:100)

50,000 HRS with

90%

MB35:
SES LOW(10% - 2
0%)
SES HIGH(20% ­30%)

LED Life : 30,000 Hours(Min)

-Test Condition

Margin:

p: >7%

Ty

Confidence level

5

,000 m (for Reliability) 3,000m(for FOS)

Temperature
Humidity
Temperature
Humidity

10 °C ~ 35 °C
10% ~ 80%

-20 °C ~ 60 °C
5% ~ 90% non-condensing

BRIGHTNESS BRIGHTNESS (0 ~ 100)

(1)

ORIGINAL

RATIO

COLOR

Temperature

VOLUME VOLUM

CONTAST CONTAS

Reader mode Custom/reader1/read

Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes

WIDE

ORIGINAL

Warm

Preset

MEDIUM

Custom

COOL

E( 0 ~ 100)

T(0 ~ 100)

er2

- 8 -

LGE Internal Use Only