LG MBD-K203Q Schematic

MODEL : MBD-K203Q (FBS203V)

SERVICE MANUAL

P/NO : AFN542679853 MARCH, 2008

KARAOKE MINI Hi-Fi SYSTEM

SERVICE MANUAL

CAUTION

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

MODEL : MBD-K203Q (FBS203V)

Website http://biz.lgservice.com

Internal Use Only

1-1

LGE Internal Use Only

[CONTENTS]

❍ SECTION 1. GENERAL

• SERVICING PRECAUTIONS ................................................................................................ 1-2

• ESD PRECAUTIONS ............................................................................................................ 1-4

• SERVICE INFORMATION FOR EEPROM ............................................................................ 1-5

• PROGRM DOWNLOAD GUIDE ............................................................................................ 1-7

• SPECIFICATIONS .............................................................................................................. 1-11

❍ SECTION 2. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION.............................................................................. 2-1

•

DECK MECHANISM EXPLODED VIEW................................................................................ 2-3

•

SPEAKER EXPLODED VIEW .............................................................................................. 2-5

• PACKING ACCESSORY

VIEW.............................................................................................. 2-6

❍ SECTION 3. ELECTRICAL PART

• TROUBLESHOOTING GUIDE

AUDIO PART TROUBLESHOOTING GUIDE ........................................................................ 3-1

DVD PART TROUBLESHOOTING GUIDE .......................................................................... 3-11

• WAVEFORMS OF MAJOR CHECK POINT ........................................................................ 3-19

• WIRING DIAGRAM .............................................................................................................. 3-25

• BLOCK DIAGRAM .............................................................................................................. 3-26

• CIRCUIT DIAGRAMS .......................................................................................................... 3-27

• INTERNAL BLOCK DIAGRAM OF IC ................................................................................ 3-47

• CIRCUIT VOLTAGE CHART ................................................................................................ 3-63

• PRINTED CIRCUIT DIARGAMS ........................................................................................ 3-67

❍ SECTION 4. REPLACEMENT PARTS LIST ................................................................ 4-1

1-2

Only for training and service purposes

LGE Internal Use Only

SERVICING PRECAUTIONS

NOTES REGARDING HANDLING OF THE PICK-UP

1. Notes for transport and storage

1) The pick-up should always be left in its conductive bag until immediately prior to use.

2) The pick-up should never be subjected to external pressure or impact.

2. Repair notes

1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.

2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or damage to the printed-circuit board.

3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason the adjustment point and installation screws should absolutely never be touched.

4) Laser beams may damage the eyes! Absolutely never permit laser beams to enter the eyes! Also NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.

5) Cleaning the lens surface

If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cotton swab should be used, taking care not to distort this.

6) Never attempt to disassemble the pick-up. Spring by excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab. (Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.

Storage in conductive bag

Drop impact

NEVER look directly at the laser beam, and don’t allow contact fingers or other exposed skin.

Magnet

How to hold the pick-up

Conductive Sheet

Cotton swab

Pressure

SECTION 1. GENERAL

1-3

LGE Internal Use Only

NOTES REGARDING COMPACT DISC PLAYER REPAIRS

1. Preparations

1) Compact disc players incorporate a great many ICs as well as the pick-up (laser diode). These components are sensitive to, and easily affected by, static electricity. If such static electricity is high voltage, components can be damaged, and for that reason components should be handled with care.

2) The pick-up is composed of many optical components and other high-precision components. Care must be taken, therefore, to avoid repair or storage where the temperature of humidity is high, where strong magnetism is present, or where there is excessive dust.

2. Notes for repair

1) Before replacing a component part, first disconnect the power supply lead wire from the unit

2) All equipment, measuring instruments and tools must be grounded.

3) The workbench should be covered with a conductive sheet and grounded. When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is because there is the possibility of damage by static electricity.)

4) To prevent AC leakage, the metal part of the soldering iron should be grounded.

5) Workers should be grounded by an armband (1M Ω)

6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent static electricity changes in the clothing to escape from the armband.

7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.

Resistor (1 Mohm)

Conductive Sheet

Resistor (1 Mohm)

Armband

1-4

Only for training and service purposes

LGE Internal Use Only

Electrostatically Sensitive Devices (ESD)

Some semiconductor (solid state) devices can be damaged easily by static electricity. Such components commonly are called Electrostatically Sensitive Devices (ESD). Examples of typical ESD 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 your 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 ESD 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 ESD 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 ESD devices.

5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESD

devices.

6. Do not remove a replacement ESD device from its protective package until immediately before you are

ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive materials).

7. Immediately before removing the protective material from the leads of a replacement ESD device, touch the

protective material to the chassis or circuit assembly into which the device will by installed.

CAUTION : BE SURE NO POWER IS APPLIED TO THE CHASSIS OR CIRCUIT, AND OBSERVE ALL OTHER

SAFETY PRECAUTIONS.

8. Minimize bodily motions when handing unpackaged replacement ESD 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 ESD device).

CAUTION. GRAPHIC SYMBOLS

THE LIGHTNING FLASH WITH APROWHEAD SYMBOL. WITHIN AN EQUILATERAL TRIANGLE, IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF UNINSULATED “DANGEROUS VOLTAGE” THAT MAY BE OF SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF ELECTRIC SHOCK.

THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.

SAFETY PRECAUTIONS

1-5

LGE Internal Use Only

SERVICE INFORMATION FOR EEPROM (MICOM PART)

POWER ON

FLD no disc status

Remote control ‘2’ + Front ‘STOP’

push same timing during 5s

FLD ‘OP-0….

Use arrow key ( ) move to appropriate position and make changes

Press ENTER key once

FLD ‘write ok’

Remote control ‘2’ + Front ‘STOP’

push same timing

FLD display E2P CLR or EP CLR

Auto power off

MODEL : FBD203 NAME HEX

OPT 1 00 OPT 2 00 OPT 3 00 OPT 4 00 OPT 5 00

DETECT NEW EEPROM (OPTION EDIT SCREEN)

1-6

Only for training and service purposes

LGE Internal Use Only

SERVICE INFORMATION FOR EEPROM (DVD PART)

POWER ON

DVD LOGO Status (NO Disk status)

Remote control Pause key-->1-->4-->7-->2 in order.

Press number 0~9, Press character A~F (1~6 for a while)

Use arrow key ( ) to move to appropriate position and make changes

Press pause key once

Change will be applied when power

OFF-->ON.

NAME

OPT 1 OPT 2 OPT 3 OPT 4 OPT 5 OPT 6 OPT 7 OPT 8 OPT 9 OPT A OPT B OPT C OPT D OPT E OPT F OPT G

HEX

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

DETECT NEW EEPROM (OPTION EDIT SCREEN)

1-7

LGE Internal Use Only

PROGRM DOWNLOAD GUIDE

• AUDIO USB DOWNLOAD GUIDE

The name of the program file to download is FBD203_date.hex.

- At some PCs with the security program (Water Wall) installed, store it at the USB device, disable the security protection, and download it to the set.

Note) Do not perform any other work such as disconnecting the USB device, switching to the

other Function and turning off the power while downloading it to the set. The USB device should be disconnected after completing the download.

1. When the USB device is inserted at the USB function a after a while TV screen is displayed on the as following figure.

1-8

Only for training and service purposes

LGE Internal Use Only

2. The message “Upgrade” is displayed while downloading.

3. The power is automatically turned off when downloading is completed.

1-9

LGE Internal Use Only

• DVD USB DOWN LOAD GUIDE

The program file to download should be named as BANK30.ROM.

- The downloaded file should be modified as BANK30.ROM to use.

- At some PCs with the security program (Water Wall) installed, store BANK30.ROM at the USB

device, disable the security protection, and download it to the set.

- After safely storing BANK30. ROM at the USB device, perform the following steps.

Note) Do not perform any other work such as disconnecting the USB device, switching to the

other Function and turning off the power while downloading it to the set.

1. When the USB device is inserted at the USB functiona after a while TV screen is displayed on the as following figure.

2. When downloading is completed, the message “Completed” is displayed at the top left of the TV screen as shown at Figure(1). If the message “NO USB” is displayed as shown at Figure(2), downloading is completed.

FIG.1

FIG.2

1-10

Only for training and service purposes

LGE Internal Use Only

3. Turn on the power, press the SETUP button of the remote controller at the USB FUNCTION. When the SETUP window is displayed on the screen, move down once to select the DISPLAY menu. Go to the TV Aspect at the right menu, move to “16:9”, enter “1397139” by using the numeric key of the remote controller, and then press the Enter key. Then, the System Information screen is displayed as shown inthe following figure. If not, retry the steps at the above.

4. When Step 3 is completed, press the PAUSE KEY of the remote controller.

5. Disconnect the power code, and reconnect it after 5 seconds to complete downloading.

7. When the power is turned on again, the language selection menu is initially displayed.

After selecting the desired language, press the SELECT/ENTER.

Left Right

Down

1-11

LGE Internal Use Only

SPECIFICATIONS

General

Power supply Refer to main label. Power consumption Refer to main label. Net Weight 3.42 kg External dimensions (W x H x D) 330 x 138.5x 252.4 mm Operating conditions Temperature: 5° C to 35° C, Operation status: Horizontal Operating humidity 5% to 85%

Tuner

FM Tuning Range 87.5 - 108.0 MHz or 65.0 - 74.0 MHz, 87.5 - 108.0 MHz Intermediate Frequency 10.7 MHz AM Tuning Range 522 - 1,620 kHz or 520 - 1,720 kHz Intermediate Frequency 450 kHz

Amplifier

OUTPUT POWER 100 W + 100 W (4Ω, THD 0.5%) : MBD- K203Q

50 W + 50 W( 4Ω, THD 0.5%) : MBD- K103Q

Stereo Mode 100 W + 100 W (4Ω, THD 0.5%) : MBD- K203Q

50 W + 50 W( 4Ω, THD 0.5%) : MBD- K103Q Frequency Response 40 - 20000Hz Signal- to- noise ratio 75dB

DVD/ VCD/ CD player

Frequency response (audio) 40 - 20000 Hz Signal- to- noise ratio (audio) More than 75 dB (1 kHz) Signal- to- noise ratio (video) More than 55 dB (1 kHz) Dynamic range (audio) More than 80 dB Video output 1.0 V (p- p), 75 Ω Component Video output (Y) 1.0 V (p- p), 75 Ω

Speakers

FBS203V Type 2Way 2Speaker Impedance 4 Ω Rated Input Power 100 W Max. Input Power 200W Net Dimensions (W x H x D) 165 X 341 X 261 mm Net Weight 4.48 kg

Designs and specifications are subject to change without pior notice.

1-12

Only for training and service purposes

LGE Internal Use Only

2-1 2-2

LGE Internal Use Only

• CABINET AND MAIN FRAME SECTION

SECTION 2. EXPLODED VIEWS

453

NOTES) THE EXCLAMATION POINT WITHIN AN

EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE

B

LITERATURE.

453

A42

257

A46

A

C

MAIN

E

SCART

B

471

F

273

A43

453

CABLE2

259

FRONT

F

MIC

G

H

I

258

453

D

G

471

CABLE1

A47

C

SMPS

453

A

E

453

271

254

253

271

255

256

453

H

I

CABLE3

260

A26

272

D

270

A44

271

465

250

453

300

2-3 2-4

Only for training and service purposes

LGE Internal Use Only

DECK MECHANISM EXPLODED VIEW

1. DECK MECHANISM SECTION (DP-10)

A26

012

019

013

017

439

014

435

015

018

015B

015A

016

012

440

030

001

002

003

432

A01

A02

020

012A

010

026

A03

036

025

021

439

430

431

435

024

012A

2-5

LGE Internal Use Only

• FRONT SPEAKER (FBS203V)

SPEAKER EXPLODED VIEW

851

852

A80L

A80R

A81A

853

854

A81L

A81R

860

863

858

857

856

862

855

861

865L

865R

859

2-6

Only for training and service purposes

LGE Internal Use Only

• PACKING ACCESSORY

VIEW

808 Battery

900 Remote Control

801 Instruction Ass'y

811

Plug Ass'y, 1Way

Antenna Loop

824

827

825 Antenna

Micro Phone

832

DISC

803 Packing

804 Bag

801S

Song Book

803 Packing

802 Box

3-1

LGE Internal Use Only

1. MICOM PART CHECK I

OK OK

NO

NO NO

Replace the

related parts.

Check if output voltage

of IC101 KIA7042 is

4.3V.

YES

YES YES

Check IC100

LC87F5NC8A 4 PIN

power.

YES

Refer to SMPS

troubleshooting.

MICOM PART

HECK I

Check

CN101 6PIN

P-SENS.

NO

Check

power of both

terminals of IC101

KIA7042

Check if IC101 KIA7042 input is over 5V.

Check the

related part of IC101

KIA7042.

AUDIO ELECTRICAL TROUBLESHOOTING GUIDE

SECTION 3. ELECTRICAL PART

3-2

Only for training and service purposes

LGE Internal Use Only

2. MICOM PART CHECK II

NO

YES

Refer to SMPS

Troubleshooting.

NO

Check D101 RS1G

output is working on 5V.

Check IC103 8PIN IC100

14,55,89 PIN 5V

YES

OK

YES

Check Q102 COLLECTOR

YES

Check the related part.

Replace the related parts.

Check the working condition

X100:32.768kHz

X101:9.8304MHz

Check CN101 5PIN 5.6V

Check power

of both terminals of D101

RS1G.

YES

NO

Check Q10

EMITTER 5V and

COLLECTOR 5V

Check the related part

MICOM PART CHECK II

NO

Replace the related parts.

Check Q102 BASE

PIN 0.6V HIGH

NO

Check output power of IC101

KIA7042 is over 4.3V.

Check the

related part.

NO

Replace the related parts.

OK

YES

OK

YES

OK

3-3

LGE Internal Use Only

3. IC103 S-24CS16A01 PART CHECK

YES

81 PIN DATA 82 PIN CLK

Check the related part.

NO

Check MICOM power 5V

CHECK IC100 LC87F5NC8A

81,82 PIN

NO

Replace the related parts.

NO

Refer to micom

troubleshooting.

OK

3-4

Only for training and service purposes

LGE Internal Use Only

4. FLD DISPLAY PART CHECK

NO

YES

Refer to SMPS

Troubleshooting

NO

Replace the related part

Check P3101 assembly

F1+,F2-both terminals:over

3.7V Check power VKK:over

-28V.

YES

FLT light on?

Check

CN101 1,2,3 power.

YES

Check

P3101 connection

condition and power F1+,F2-

both terminals:over 3.7V

Check power VKK:over -28V

Check 4,5 PIN:5.6V

YES

Check

IC304 PT6324

power 50 PIN VKK:-28V

9.52 PIN +5V

YES

Check

power of each PIN.

IC100

Check→IC304

Data communication.

PIN PIN 27PIN→3PIN STB 26PIN→2PIN DO 28PIN→1PIN CLK

OK

NO

Replace the related part.

NO

Replace the related part.

NO

When 5V fails,check D321SR35

input and output power.

IC100 27 PIN→STB

28 PIN→1PIN CLK

Check Data output.

Check 26 PIN→DO

→DATA input.

YES

Check the related part

YES

Check the related part

OK

YES

FLD DISPLAY CHECK

3-5

LGE Internal Use Only

5. TOUCH-PAD PART CHECK

NO

YES

PN3A2 1PIN 5V.

NO

Replace the related part.

NO

Refer to SMPS

Troubleshooting.

Check resistance output of

line CLK :R3A2 DATA :R3A3

IC3A1

28PIN check 5V.

Check

IC3A1 8Pin,9Pin,

IC100 97Pin :CLK,

96Pin :DATA

TOUCH-PAD CHECK

YES

OK

YES

OK

YES

OK

6. PWM MODULATION PART CHECK

Check

PN102 10PIN 3.3V.

PWM MODULATION

PART CHECK

Refer to SMPS

Troubleshooting.

NO

Check if X701

12.288MHz is working.

YES

Check IC702 PS9830 VDD

PIN power (3,10,22,29,39,47,

56,65,72,87,94)Check X701

2PIN 3.3V

Replace the related part.

NO

YES

Check the

related part of

X701.

OK

NO

3-6

Only for training and service purposes

LGE Internal Use Only

NO

Check

output of IC100

LC87F5NC8A

21→PWM_CLK

22→PWM_DATA

43→PWM_REST

YES

Check IC702

PS9830 DATA input

78 PIN→DATA

79 PIN→CLK

96 PIN→REST

Check

PWM MODULATOR

output

FL:75(+)74(-)

R:71(+)70(-)

OK

Replace the related part.

NO

Check

resistance output of LINE

DATA:R797

CLK:R795 RST:R790

Refer to DVD Troubleshooting.

NO

Check DVD

ASS`Y PS9830

communication condition

(P7403)

YES

OK

Check IC702 PS9830 part.

Check resistance

output of each LINE.

NO

Check IC702

PS9830 DATA input.

OK

YES

Check IC702 PS9830

86 PIN CLK input

Replace the related part.

NO

YES

Check R791(1M)output

OK

NO

3-7

LGE Internal Use Only

7. PWM AMP PART CHECK

YES

NO

Refer to SMPS Troubleshooting.

PN102

3PIN + 13,14,15 PIN 28V.

YES

NO

Check resistance power

IC700:R702,701,726,727,724.

Check input power of IC700,

1,36,17,18,19 PIN +12V

YES

NO

Replace the related parts.

Check output LINE COIL.

POWER AMP PART CHECK

OK

Check input power IC700

34,29,26,21 PIN.

YES

Check PWM MODULATOR

input 4,6,14,16 PIN.

YES

Check POWER IC 700 34,

29,27,20 PIN output.