LG MCD102, MCS102F Schematic

MINI Hi-Fi SYSTEM

SERVICE MANUAL

MODEL : MCD102 (MCS102F)

CAUTION

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

MODEL : MCD102 (MCS102F)

SERVICE MANUAL

http://biz.lgservice.com

P/NO : AFN32840849 FEBRUARY, 2007

1-1

CONTENTS

SECTION 1 GENERAL

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

• NOTES REGARDING HANDLING OF THE PICK-UP

•

NOTES REGARDING COMPACTDISC PLAYER REPAIRS

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

LOCATION OF USERS CONTROLS.........................1-5

SPECIFICA TIONS........................................................1-7

SECTION 2 EXPLODED VIEWS

CABINET EXPLODED VIEW......................................2-1

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

1. TAPE DECK MECHANISM

(A/S & A/S : RIGHTA/S DECK)........................2-3

2. TAPE DECK MECHANISM

(A/S & A/S : LEFTA/S DECK) ..........................2-5

CD MECHANISM EXPLODED VIEW.........................2-7

SPEAKER EXPLODED VIEW ....................................2-9

MODEL : MCS102F ...............................................2-9

PACKING ACCESSORY VIEW.................................2-13

SECTION 3 AUDIO PART ELECTRICAL

AUDIO ELECTRICAL

TROUBLESHOOTING GUIDE....................................3-1

1. POWER (SMPS)................................................3-1

2. P-SENS...............................................................3-2

3. VKK CHECK.......................................................3-2

4. MICOM PART CHECK I ....................................3-2

5. MICOM PART CHECK II ...................................3-3

6. IC103(KS4CD21CS) CHECK............................3-4

7. FLD DISPLAY CHECK ......................................3-5

8. PWM MODULATION PART CHECK................3-6

9. POWER AMPPART CHECK............................3-7

10. AUX FUNCTION CHECK..................................3-8

11. TUNER FUNCTION CHECK.............................3-9

12. TAPE FUNCTION CHECK..............................3-10

13. T APE PLAY PAR TCHECK..............................3-11

14. TAPE REC PART CHECK...............................3-12

INTERNAL BLOCK DIAGRAM OF ICs...................3-13

1. ES6838 ..............................................................3-13

2. HA12237F..........................................................3-14

3. PS9829B............................................................3-15

4. PT6324...............................................................3-15

5. STR-S6757IF1905 ............................................3-16

6. T AS5142.............................................................3-17

7. U1739EJ2V1UD00/KF2_E...............................3-18

WIRING DIAGRAM....................................................3-20

BLOCK DIAGRAM.....................................................3-22

1. SMPS BLOCK DIAGRAM...............................3-22

2. MAIN & FRONT BLOCK DIAGRAM ..............3-24

SCHEMATIC DIAGRAMS .........................................3-26

1. SMPS SCHEMATIC DIAGRAM.......................3-26

2. MAIN SCHEMATIC DIAGRAM........................3-28

3. AMP SCHEMATIC DIAGRAM..........................3-30

4. DECK SCHEMATIC DIAGRAM.......................3-32

5. FRONT SCHEMATIC DIAGRAM.....................3-34

PRINTED CIRCUIT DIAGRAMS...............................3-36

1. MAIN P.C.BOARD............................................3-36

2. SMPS P.C.BOARD ..........................................3-40

3. FRONT P.C.BOARD........................................3-42

SECTION 4 CD PART ELECTRICAL

CD ELECTRICAL TROUBLESHOOTING GUIDE....4-1

1. CD PART TROUBLESHOOTING.....................4-1

2. USB PART TROUBLESHOOTING...................4-9

WAVEFORMS OF MAJOR CHECK POINT............4-10

SCHEMATIC DIAGRAMS .........................................4-13

1. CD SCHEMATIC DIAGRAM...........................4-13

2. USB SCHEMATIC DIAGRAM.........................4-15

PRINTED CIRCUIT DIAGRAM.................................4-17

CD P.C.BOARD....................................................4-17

SECTION 5 REPLACEMENT PARTS LIST

........5-1

1-2

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.

SERVICING PRECAUTIONS

SECTION 1 GENERAL

1-3

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 (1MΩ)

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.

CLEARING MALFUNCTION

You can reset your unit to initial status if malfunction occur(button malfunction, display, etc.). Using a pointed good conductor(such as driver), simply short the RESET jump wire on the inside of the volume knob for more than 3 seconds. If you reset your unit, you must reenter all its settings(stations, clock, timer)

NOTE: 1. To operate the RESET jump wire, pull the volume rotary knob and release it.

2. If you wish to operate the RESET jump wire, it is necessary to unplug the power cord.

1-4

ESD PRECAUTIONS

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 know 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 ARROWHEAD 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 INTENED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE.

1-5

LOCATION OF USERS CONTROLS

FRONT / BACK PANEL

1. DISPLAY WINDOW

2. • (POWER) button

• OPEN/ CLOSE button

3. • XDSS/ MP3 OPT. button

• XTS - PRO button

4. • USB (OPTIONAL) / DEMO button

• USB connector (OPTIONAL)

• PHONES (HEADPHONE JACK) : ø3.5mm

5. • TUNER button

• AUX button

6. • PUSH EJECT position - TAPE 1

7. • PUSH EJECT position - TAPE 2

8. • TUNING (-/+) button

(REWIND / FAST FORWARD) button

(CD SKIP / SEARCH) buttons

• PRESET (-/+) button FORWARD PLAY ( ) button

•STOP button

9. • CD button

• TAPE button

10.•CLOCK button

• TIMER button

• RDS(OPTIONAL) / SET / CD button

• EQ. button

• CD SYNC. / DUBB / ST./MONO button

• REC/

• VOLUME CONTROL KNOB

11.DISC SELECT buttons (DISC1, DISC2, DISC3)

12.DISC TRAY

13.AM/ FM ANTENNATERMINAL

14.AUX IN (AUXILIARY INPUT) connector

15.POWER CORD

16.SPEAKER TERMINAL

1 2

3 4

5 6

11 10

8 7

14 15

1-6

REMOTE CONTROL

POWER button

PRESET/FOLDER( ) buttons

SLEEP button

CD FUNCTION buttons

PLAY/PAUSE ( ) button •

CD STOP( ) button •

CD SKIP/ SEARCH •

() buttons

TUN.(-/+) buttons •

REPEAT button •

D.SKIP button

EQ (EQUALIZER PATTERN) button •

XTS Pro button •

XDSS plus button •

NUMERIC buttons

MUTE button

• USB (OPTIONAL) button

• FUNCTION button VOLUME ( ) buttons

DIMMER button PROGRAM/ MEMO button TAPE FUNCTION buttons

• FORWARD PLAY ( ) button

• FAST REWIND PLAY ( ) button

• FAST FORWARD PLAY ( ) button

• TAPE-1/ 2 SELECT buttons

• RECORD/ RECORD PAUSE ( ) button

• TAPE STOP ( ) button

RANDOM button INFO (MP3/ WMA file information display) button

1-7

SPECIFICATIONS

• GENERAL

Power supply Refer to the back panel of the unit. Power consumption Refer to the back panel of the unit. Net Weight 5.57kg (MCD202 Model)

5.36kg (MCD102 Model)

External dimensions (WxHxD) 273 x 371 x 326mm

• TUNER

FM Tuning Range 87.5 ~ 108.0MHz or 65 ~ 74MHz, 87.5 ~ 108.0MHz Intermediate Frequency 10.7MHz Signal to Noise Ratio 60/55dB Frequency Response 50 ~ 10000Hz AM Tuning Range 522 ~ 1620kHz or 520 ~ 1720kHz Intermediate Frequency 450kHz Signal to Noise Ratio 30dB Frequency Response 140 ~ 1800Hz

• AMPLIFIER

Output Power 100W + 100W (MCD202 Model)

50W + 50W (MCD102 Model) T.H.D 0.5% Frequency Response 40 ~ 20000Hz Signal-to-noise ratio 75dB

• CD

Frequency response 40 ~ 20000Hz Signal-to-noise ratio 75dB Dynamic range 75dB

• CASSETTE TAPE PLAYER

Tape Speed 3000 ± 3% (MTT-111. NORMAL-SPEED) Wow Flutter 0.25% (MTT-111, JIS-WTD) F.F/REW Time 120sec (C-60) Frequency Response 250 ~ 8000Hz Signal to Noise Ratio 43dB Channel Separation 50dB (P/B) / 45dB (R/P) Erase Ratio 55dB (MTT-5511)

• SPEAKERS Speaker Name MCS202F MCS102F

Type Bass Reflex 2Way 2Speaker Bass Reflex 2Way 2Speaker Impedance 4Ω 4Ω Frequency Response 60 ~ 20000Hz 60 ~ 20000Hz Sound Pressure Level 84dB/W (1m) 85dB/W (1m) Rated Input Power 100W 50W Max. Input Power 200W 100W Net Dimensions (WxHxD) 220 x 342 x 270mm 200 x 337 x 228mm Net Weight (1EA) 3.46kg 2.92kg

A26

A41

A44

A40

A47

A46

266

263

305

A43

451

450

267

289

456

450

264

458

450

290

454

450

A00

257

255

256

259

253

282

253

254

450

CABLE2

CABLE4

CABLE3

CABLE1

CABLE5

CN201

CN806

P9701

P9702

260

MAIN

SMPS

FRONT

291

2-1 2-2

SECTION 2 EXPLODED VIEWS

CABINET EXPLODED VIEW

2-3 2-4

TAPE DECK MECHANISM EXPLODED VIEW

1. TAPE DECK MECHANISM (A/S & A/S : RIGHT A/S DECK)

BRASS MOTOR PULLEY MAYBE CHANGED FOR WOW FLUTTER WHEN NECESSARY

009

003

A00

001

002

007

008

022

006

016

015

017

023

018

019

025

020

A01

RING FW MAYBE ADDED FOR WOW FLUTTER WHEN NECESSARY

011

009

A02

013

2-5 2-6

2. TAPE DECK MECHANISM (A/S & A/S : LEFT A/S DECK)

019

A00

003

009

007

008

016

017

022

018

023

015

020

RING FW MAYBE ADDED FOR WOW FLUTTER WHEN NECESSARY

024

011

009

A03

013

2-7 2-8

416

151

159

165

164

417

166

417

167

416

177

175

172

170

419

417

418

190

189

188

A30

A32

A26

181

187

186

184

421

185

156

155

153

173

168

163

162

441

440

422

A35

417

CD MECHANISM EXPLODED VIEW

2-9 2-10

SPEAKER EXPLODED VIEW

MODEL : MCS102F

A80

A80A

A80B

855

853

850

854

852

851

856

WIRE80

2-13

PACKING ACCESSORY VIEW

3-1

AUDIO ELECTRICAL TROUBLESHOOTING GUIDE

SECTION 3 AUDIO PART ELECTRICAL

1. POWER (SMPS)

POWER (SMPS)

YES

Replace IC 901,902

Check IC901, 902

Check the fuse

F901

NONO

YES

Check short of

P9701, P9702 line

Replace the fuse

Check

the DC V of C905.

If DC V is over

400V

Check BD901, LF901, 902

Check the

DC V of C981, C945.

If DC V is 6.1V

Check short of P9702 line

YES

Chcek the

DC V of C950, C951

If DC V is in

31.5V

Check short of P9701 line

Chcek the

DC V of C909, C903,

C921 If DC V is in 14~19V

and it is steady.

YES

3-2

2. P-SENS

P-SENS

YES

Check

the PIN6 of P9702

If DC V is over 5.6V

Check power circuit Trouble shooting

3. VKK CHECK

VKK check

YES

Check

the PIN3 of P9702

If DC V is over -28V ±2

Check power circuit Trouble shooting

4. MICOM PART CHECK I

MICOM part check I

OK OK

YES

Check P-SENS

(P7904)_PIN6.

Refer to

SMPS troubleshooting.

YES

Check both

end voltage of IC101

(KIA7042).

Check

if input voltage of

IC101(KIA7042) is

over 5V.

YES

Check the

periphery of IC101

(KIA7042).

YES

Check if IC101(KIA7042) of output voltage is over 4.3V.

Check voltage of IC100

78KO/KF2_PIN1.

Replace IC101

(KIA7042).

3-3

5. MICOM PART CHECK II

MICOM part check II

X101 : 32.768kHz

X100 : 9.8304MHz

Check the operation.

Check

Q101_ emitter/collector

5V.

Check Q102_base

0.6V HIGH.

Check if IC103_PIN8 and

IC100_PIN19, 20, 59 are 5V.

NO NO

YES

Check if

voltage of P7904_PIN5

is 5.6V.

Refer to

SMPS troubleshooting.

YES

Check

both end voltage of

D101

YES

Check D101.

Check if output of

D101(1SR35) is 5V.

YES

Check IC101.

Q102_collector 0.6V LOW.

Check if output of IC101

(KIA7042) is over 4.3V.

Replace IC101.

Replace D101.

YES

Check Q102.

Replace Q102.

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