LG LX M330A Service Manual

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[CONTENTS]

❍ SECTION 1. GENERAL

• SERVICING PRECAUTIONS

.....................................................................................................

1-2

• ESD PRECAUTIONS

.................................................................................................................

1-4

• SPECIFICATION

........................................................................................................................

1-5

❍ SECTION 2. TROUBLESHOOTING

• ADJUSTMENTS

.........................................................................................................................

2-1

• TROUBLESHOOTING ............................................................................................................... 2-2

• WAVEFORMS OF MAJOR CHECK POINT............................................................................. 2-11

• BLOCK DIAGRAM

....................................................................................................................

2-21

• SCHEMATIC DIAGRAMS

........................................................................................................

2-23

• WIREING DIAGRAM ................................................................................................................ 2-29

• PRINTED CIRCUIT DIAGRAMS .............................................................................................. 2-31

• INTERNAL BLOCK DIAGRAM OF ICs .................................................................................... 2-38

❍ SECTION 3. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION

...................................................................................

3-1

❍ SECTION 4. SPEAKER PART

• SPEAKER PART

........................................................................................................................

4-1

❍ SECTION 5. REPLACEMENT PARTS LIST

• REPLACEMENT PARTS LIST

....................................................................................................

5-1

❏ 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.

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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

Pressure

Cotton swab

Conductive Sheet

SECTION 1. GENERAL

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.

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Armband

Conductive Sheet

Resistor (1 Mohm)

VOLUME KNOB

DOWN

VOLUME

RESET jump wire

❐ 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

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]

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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.

❏ SPECIFICATIONS

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SECTION MODEL SPECIFICATION

General Power supply Refer to the back panel of the unit

Power consumption 65W

Extemal dimensions(W X H X D)

161 X 255 X 268mm

CD Frequency Response 40 -18000Hz

Signal-to-noise ratio 70dB

Dynamic range 70dB

Tuning Range 87.5 -108.0MHz

Intermediate Frequency 10.7 MHz

FM Signal-to-noise ratio 60/55dB

Frequency Response 60 - 10000Hz

Tuning Range 522 - 1611kHz or 530 - 1610kHz

AM Intermediate Frequency 450kHz

Signal-to-noise ratio 35dB

Frequency Response 100 -1800 Hz

AMP Output Power 30W + 30W

T.H.D 0.15%

Frequency Response 40-25000Hz

Signal-to-noise ratio 80dB

TAPE Tape Speed 4.75cm/sec

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)

Speaker MODEL LXS-M330

Type 2 Way 2 Speaker

Impedance 6Ω

Frequency Response 80-20000Hz

Sound Pressure Level 87dB/W(1m)

Rated Input Power 30W

Max.Input Power 60W

Net Dimension(W X H X D) 160 X 248 X 200mm

NOTE : Specification are subject to change without notice in the course of product improvement.

TUNER

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MEMO

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TAPE DECK ADJUSTMENT

1. AZIMUTH ADJUSTMENT

Figure 1. Azimuth Adjustment Connection Diagram

CH1 CH2

Speaker Out

Playback Mode

Head

Test Tape MTT-114

L ch

R ch

GND

Dual-trace synchroscope

Electronic Voltmeter

L out

R out

Unit

❏ ADJUSTMENTS

This set has been aligned at the factory and normally will not require further adjustment. As a result, it is not recommended that any attempt is made to modificate any circuit. If any parts are replaced or if anyone tampers with the adjustment, realignment may be necessary.

IMPORTANT

1. Check Power-source voltage.

2. Set the function switch to band being aligned.

3. Turn volume control to minimum unless otherwise noted.

4. Connect low side of signal source and output indicator to chassis ground unless otherwise specified.

5. Keep the signal input as low as possible to avoid AGC and AC action.

Deck Mode Test Tape Test Point Adjustment Adjust for

Palyback MTT-114 Speaker Out

DECK Screw

Maximum

Azimuth Screw

SECTION 2. ELECTRICAL SECTION

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❏ TROUBLESHOOTING

• CD PART

TURN ON CD

OPEN CLOSE CHECK

CONNECTOR CHECK ( PN508,PN507 )

CHECK POWER SUPPLY CIRCUIT( PN508 )

CHECK MICOM INTERFACE CIRCUIT( PN507 )

CONNECTOR CHECK(PN501,PN503)

CHECK PICKUP MOVEMENT

CHECK BA5810FP (IC503)

CHECK MN6627933CG (IC501)

CHECK AN22004 (IC502)

CONNECTOR CHECK (PN508)

CONNECTOR CHECK

( PN508,PN507,PN503,PN501 )

“ READING ”

DISPLAY CHECK

READING OK CHECK

IF PLAY, AUDIO

OUTPUT CHECK

YES

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DEFECTIVE MAIN

POEWR SUPPLY

DEFECTIVE MICOM

DEFECTIVE IC503

DEFECTIVE MICOM

MECHANISM

• OPEN CLOSE NG

CONNECTOR LOCKING CHECK ( PN508,PN507 )

CHECK POWER SUPPLY CIRCUIT( PN508

,PN507) PN 508 PIN 8 = 6.2V, PIN 7 = 5V

PN507 PIN 1 = 5V

CHECK VOLTAGE CHANGE OF OPEN CLOSE,

AND BTLMUTE VOLTAGE(= 5V)

(PN507 PIN 12:OPEN, 13:CLOSE, 14:BTLMUTE)

CHECK VOLTAGE CHANGE LO+, LO- OF IC503

(PN507, PIN OPEN:12, CLOSE:13)

YES

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

CONNECTOR LOCKING CHECK

(PN508,PN507,PN503,PN501 )

CHECK VOLTAGE THE PIN 2 OF

IC505 PIN2 : 3.3V

CHECK RESET SIGNAL OF PN507

PN507 PIN7 : 5V

CHECK MICOM INTERFACE

CIRCUIT( PN507 )

PN507 PIN 6,8,9,10 SIGNAL CHECK

(6: STAT, 8: MDATA, 9:MCLK, 10:MLD)

CHECK THE WAVE FORM #1

CHECK POWER SUPPLY

PORT( PN508 ,PN507)

PN508 PIN 8 = 6.2V, PIN 7 = 5V

PN507 PIN 1 = 5V

DEFECTIVE CONNECTOR OR

MAIN POWER SUPPLAY

DEFECTIVE IC505

DEFECTIVE MICOM OR

CONNECTOR

DEFECTIVE MICOM OR

CONNECTOR

DEFECTIVE IC501

YES

YESYES

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

AAAA

BBBB

CCCC

DDDD

EEEE

CONNECTOR LOCKING

CHECK(PN501,PN503)

DOES LENSE MOVE ?

(= UP & DOWN)

DOES SLED MOVE ?

CHECK PN503 PIN 3,4( SL+,SL-)

CHECK PN501 PIN 13,16

( FA-, FA+)

DEFECTIVE PICKUP OR

IC503 OR IC501 OR IC502

DEFECTIVE PICKUP OR

IC503 OR IC501

DEFECTIVE PICKUP OR

IC502

DEFECTIVE PICKUP OR

IC503

DEFECTIVE PICKUP OR

IC503 OR IC501 OR IC502

CHECK PN503 PIN 10( LD )

CHECK PN503 PIN

5,6( SP+,SP-)

CHECK PN501 PIN 14,15

(TA- ,TA+)

DOES LASER LIGHT ?

DOES SPINDLE ROTATE ?

IS READING OK ?

YES

YESYES

YES

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

AAAA

DOES SL+ WAVEFORM

APPEAR AT ( IC503 PIN14 AND

PN503 PIN3) WAVEFORM #2

SLED MOTOR WAVE

DOES SLIN WAVEFORM

APPEAR AT ( IC503 PIN 5)

WAVEFORM #2 SLED

DRIVE WAVE

DEFECTIVE IC501

DEFECTIVE IC503

CHECK PN503 CONNECTOR LINE

DEFECTIVE PN503

CONNECTOR

DEFECTIVE PICKUP

SLED MOTOR

YES

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

BBBB

DOES FA+ WAVEFORM

APPEAR AT ( IC503 PIN15 AND

PN501 PIN16) WAVEFORM #3

FOCUS COIL DRIVE WAVE

DOES FAIN- WAVEFORM

APPEAR AT ( IC503 PIN 26)

WAVEFORM #3 FOCUS

DRIVE WAVE

DEFECTIVE IC501

DEFECTIVE IC503

CHECK PN501 CONNECTOR LINE

DEFECTIVE PN501

CONNECTOR

DEFECTIVE PICKUP

FOCUS ACTUATOR

YES

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

CCCC

IS ?V APPLIED TO PIN10 OF PN501

LASER SUPPLY VOLTAGE CHECK

IS 3.3 V APPLIED TO

PIN3 OF IC502

RF IC SUPPLY VOLTAGE

CHECK

IS 2.0 V PIN2 OF IC502

LASER CONTROL VOLTAGE CHECK

DEFECTIVE IC505

DEFECTIVE IC502

CHECK PN501 CONNECTOR LINE

DEFECTIVE Q501 OR

D502

DEFECTIVE PN501

CONNECTOR

DEFECTIVE PICKUP

LASER PART

YES

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