LG LM-W2340A, LMS-W2340 Service Manual

MINI HI-FI SYSTEM

SERVICE MANUAL

CAUTION

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

P/N : 3829RAT112N JANUARY, 2005

MODEL: LM-W2340A, LMS-W2340

SERVICE MANUAL MODEL: LM-W2340A, LMS-W2340

- 1-1 -

[CONTENTS]

❍ SECTION 1.GENERAL

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

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

• SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-5

❍ SECTION 2.ELECTRICAL SECTION

• TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

• INTERNAL BLOCK DIAGRAM of ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

• BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

• SCHEMATIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27

• WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39

• PRINTED CIRCUIT BOARD DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41

❍ SECTION 3. EXPLODED VIEWS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

❍ SECTION 4. SPEAKER PART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

❍ SECTION 5. REPLACEMENT PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

- 1-2 -

❏ 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 let contact fingers or other exposed skin.

Magnet

How to hold the pick-up

Conductive Sheet

Cotton swab

Pressure

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 (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.

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.

Resistor (1 Mohm)

Conductive Sheet

Resistor (1 Mohm)

Armband

RESET jump wire

VOLUME

VOLUME KNOB

DOWN

- 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 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 sur-

face 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.

- 1-5 -

❏ SPECIFICATIONS

[General][CD]

[Tuner]

(MW)

[Amp]

[

TAPE

]

Power supply Refer to the back panel of the unit. Power consumption 220W 170w 150w 110w

Mass 12kg 10kg 10kg External dimensions (W x H x D) 280 x 370 x 372 mm Frequency response 40 - 18000 Hz Signal-to-noise ratio 70 dB Dynamic range 70 dB Tuning Range 87.5 - 108.0 MHz or 65 - 74 MHz Intermediate Frequency 10.7 MHz Signal to Noise Ratio 60/55 dB Frequency Response 60 - 10000 Hz Tuning Range 522 - 1611 kHz or 530 - 1610 kHz Intermediate Frequency 450 kHz Signal to Noise Ratio 35 dB Frequency Response 120 - 2000 Hz Output Power 310W + 310W 230W + 230W 310W + 310W 230W + 230W T.H.D 0.7% Frequency Response 42 - 25000 Hz Signal-to-noise ratio 75 dB Tape Speed 4.75cm/sec Wow Flutter 0.25% (MTT -111, JIS-WTD) F.F/REW Time 120sec (C-60) Frequency Response 125 - 8000Hz Signal to Noise Ratio 43dB Channel Separation 50dB(P/B)/45dB(R/P) Erase Ratio 55dB (MTT-5511)

Designs and specifications are subject to change without notice.

LM-W5040A/D/X

LM-W3140A/D/X

MODEL

SECTION

LM-W4040A/D/X

LM-W2340A/D/X

[Front Speakers]

Model name LMS-W5040 LMS-W4040 LMS-W3140 LMS-W2340 Type

3Way 4Speaker 3Way 4Speaker 3Way 4Speaker 3Way 4Speaker Impedance 6Ω 6Ω 6Ω 6Ω Frequency Response 45-20000Hz 45-20000Hz 45-20000Hz 45-20000Hz Sound Pressure Level 85dB 85dB 85dB 85dB Rated Input Power 250W 230W 310W 230W Max. Input Power 500W 460W 620W 460W Net Dimensions(WxHxD) 255x425x300 255x425x300 255x425x300 255x425x300 Net Weight 10.4 10.4 10.4 10.4

Model name LMS-W5040S Type 2Way 3Speak

24Ω

er Impedance Frequency Response 60-20000Hz Sound Pressure Level 85dB Rated Input Power 100W Max. Input Power 200W Net Dimensions(WxHxD) 187 x 425 x 248 Net Weight 5.3

[Surround Speakers]

Model name LMS-W5040W, LMS-W4040W Type 1W6Ωay 1Speaker Impedance Frequency Response 40-15000Hz Sound Pressure Level 83dB Rated Input Power 310W Max. Input Power 620W Net Dimensions(WxHxD) 255 x 425 x 300 Net Weight 9.2

[Woofer Speakers]

, 87.5 - 108.0 MHz

12kg

- 1-6 -

- 2-1 -

■ CD PART

❏ TROUBLESHOOTING GUIDE

TURN ON CD

CONNECTOR CHECK ( PN808,PN807 )

CHECK POWER SUPPLY CIRCUIT( PN808 )

CHECK MICOM INTERFACE CIRCUIT( PN807 )

CONNECTOR CHECK(PN801,PN802)

CHECK PICKUP MOVEMENT

CHECK BA5810FP (IC803)

CHECK MN6627933CG (IC801)

CHECK AN22004 (IC802)

CONNECTOR CHECK (PN808)

CONNECTOR CHECK

( PN808,PN807,PN802,PN801 )

OPEN CLOSE CHECK

“ READING ”

DISPLAY CHECK

READING OK CHECK

IF PLAY, AUDIO

OUTPUT CHECK

YES

SECTION 2. ELECTRICAL

- 2-2 -

CONNECTOR LOCKING CHECK ( PN808,PN807 )

DEFECTIVE MAIN

POEWR SUPPLY

DEFECTIVE MICOM

DEFECTIVE IC803

DEFECTIVE

MECHANISM

CHECK POWER SUPPLY CIRCUIT( PN808 ,PN807)

PN808 PIN 5 = 6.2V, PIN 7 = 5V

PN807 PIN 1 = 5V

CHECK VOLTAGE CHANGE OF OPEN CLOSE ,

AND BTLMUTE VOLTAGE(= 5V)

(PN807 PIN 20:OPEN, 19:CLOSE, 4:BTLMUTE)

CHECK VOLTAGE CHANGE LO+, LO- OF IC803

(PN807, PIN OPEN:20, CLOSE:19)

YES

• OPEN CLOSE NG

- 2-3 -

CONNECTOR LOCKING CHECK

(PN808,PN807,PN802,PN801 )

DEFECTIVE CONNECTOR OR

MAIN POWER SUPPLAY

DEFECTIVE IC805

DEFECTIVE MICOM OR

CONNECTOR

DEFECTIVE MICOM OR

CONNECTOR

DEFECTIVE IC801

CHECK VOLTAGE THE PIN 2 OF IC805

IC805 PIN2 : 3.3V

CHECK RESET SIGNAL OF PN807

PN807 PIN12 : 5V

CHECK POWER SUPPLY

PORT( PN808 ,PN807)

PN808 PIN 5 = 6.2V, PIN 7 = 5V

PN807 PIN 1 = 5V

CHECK POWER SUPPLY

PORT( PN808 ,PN807)

PN808 PIN 5 = 6.2V, PIN 7 = 5V

PN807 PIN 1 = 5V

CHECK MICOM INTERFACE

CIRCUIT( PN807 )

PN807 PIN 11,13,14,15 SIGNAL CHECK

(11: STAT, 13: MDATA, 14:MCLK, 15:MLD)

CHECK THE WAVE FORM #1

YES

• “ READING ” DISPLAY CHECK (= ONLY “CD “DISPLAY)

- 2-4 -

CONNECTOR LOCKING

CHECK(PN801,PN802)

DOES SLED MOVE ?

CHECK PN802 PIN 3,4( SL+,SL-)

DEFECTIVE PICKUP OR

IC803 OR IC801 OR IC802

DEFECTIVE PICKUP OR

IC803 OR IC801 OR IC802

DEFECTIVE PICKUP OR

IC803 OR IC801

DEFECTIVE PICKUP OR

IC802

DEFECTIVE PICKUP OR

IC803

DEFECTIVE PICKUP OR

IC803 OR IC801 OR IC802

CHECK PN802 PIN 10( LD )

CHECK PN801 PIN 14,15

(TA- ,TA+)

CHECK PN802 PIN

5,6( SP+,SP-)

CHECK PN801 PIN 13,16

( FA-, FA+)

DOES LENSE MOVE ?

(= UP & DOWN)

DOES LASER LIGHT ?

DOES SPINDLE ROTATE ?

IS READING OK ?

YES

• READING OK CHECK (= “NO DISC” DISPLAY)

- 2-5 -

CHECK PN802 CONNECTOR LINE

DEFECTIVE IC801

DEFECTIVE IC803

DEFECTIVE PN802

CONNECTOR

DEFECTIVE PICKUP

SLED MOTOR

DOES SL+ WAVEFORM APPEAR AT

( IC803 PIN14 AND PN802 PIN3)

WAVEFORM #2

SLED MOTOR WAVE

DOES SLIN WAVEFORM

APPEAR AT

( IC803 PIN 5)

WAVEFORM #2

SLED DRIVE WAVE

YES

• READING OK CHECK #A (= “NO DISC” DISPLAY)

- 2-6 -

CHECK PN801 CONNECTOR LINE

DEFECTIVE IC801

DEFECTIVE IC803

DEFECTIVE PN801

CONNECTOR

DEFECTIVE PICKUP

FOCUS ACTUATOR

DOES FA+ WAVEFORM APPEAR AT

( IC803 PIN15 AND PN801 PIN16)

WAVEFORM #3

FOCUS COIL DRIVE WAVE

DOES FAIN- WAVEFORM

APPEAR AT

( IC803 PIN 26)

WAVEFORM #3

FOCUS DRIVE WAVE

YES

• READING OK CHECK #B (= “NO DISC” DISPLAY)

- 2-7 -

CHECK PN801 CONNECTOR LINE

DEFECTIVE IC805

DEFECTIVE IC802

DEFECTIVE Q801 OR

D811

DEFECTIVE PN801

CONNECTOR

DEFECTIVE PICKUP

LASER PART

IS ?V APPLIED TO PIN10 OF

PN801

LASER SUPPLY VOLTAGE CHECK

IS 3.3 V APPLIED TO

PIN3 OF IC802

RF IC SUPPLY VOLTAGE

CHECK

IS 2.0 V PIN2 OF IC802

LASER CONTROL VOLTAGE CHECK

YES

• READING OK CHECK #C (= “NO DISC” DISPLAY)

- 2-8 -

CHECK PN802 CONNECTOR LINE

DEFECTIVE IC801

DEFECTIVE IC803

DEFECTIVE PN802

CONNECTOR

DEFECTIVE PICKUP

SPINDLE MOTOR

DOES SP+ WAVEFORM APPEAR AT

( IC803 PIN12 AND PN802

PIN6)WAVEFORM #4

SPINDLE MOTOR DRIVE WAVE

DOES SPIN WAVEFORM

APPEAR AT( IC803 PIN 6)

WAVEFORM #4

SPINDLE DRIVE WAVE

YES

• READING OK CHECK #D (= “NO DISC” DISPLAY)

- 2-9 -

CHECK PN802 CONNECTOR LINE

DOES ARF SIGNAL APPEAR?

(IC802 PORT 8) WAVEFORM #6

DOES FE, TE SIGNAL APPEAR?

(IC802 PORT FE:23, TE:21)

WAVEFORM #6

DEFECTIVE IC801

DEFECTIVE IC803

DEFECTIVE PN802

CONNECTOR

DEFECTIVE PICKUP OR

IC802

DEFECTIVE PICKUP OR

IC802

DEFECTIVE IC801

DOES TA+ WAVEFORM APPEAR AT

( IC803 PIN17 AND PN801 PIN15)

WAVEFORM #5

TRACKING COIL DRIVE WAVE

DOES TAIN- WAVEFORM

APPEAR AT

( IC803 PIN 23)

WAVEFORM #5

TRACKING DRIVE WAVE

YES

• READING OK CHECK #E (= “NO DISC” DISPLAY)

- 2-10 -

■ AUDIO PART

P-SENS PART CHECK

ZD 701(+) Voltage check

IC301 26PIN PATTERN Check

Half-wave rectification wave form check

R746 check, then ZD701 replacement

D713 Replacement

VKK CHECK

CN305 4pin DC -33V check

IC301 51PIN check

ZD 700 -33V check

ZD 754 turn on check

Pattern disconnection check

D707, D708 replacement

normal

ZD700 replacement

Refer to power

supply check

C763 -33V and less check

Q754 replacement

YES

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