LG LXD-5230 Service manual

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[CONTENTS]

❍ SECTION 1. GENERAL

• SERVICING PRECAUTIONS

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1-2

• ESD PRECAUTIONS

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1-4

• SPECIFICATION

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1-5

❍ SECTION 2. ELECTRICAL SECTION

• ADJUSTMENTS

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2-1

•

AUDIO PART ELECTRICAL TROUBLESHOOTING GUIDE

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• BLOCK DIAGRAM

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2-11

• SCHEMATIC DIAGRAMS

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2-13

• IC/TR VOLTAGE SHEET .......................................................................................................... 2-19

• WIREING DIAGRAM ................................................................................................................ 2-21

• PRINTED CIRCUIT DIAGRAMS .............................................................................................. 2-23

❍ SECTION 3. DVD PART ELECTRICAL TROUBLESHOOTING GUIDE

• TROUBLESHOOTING

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3-1

• DETAILS AND WAVEFORMS ON SYSTEM TEST AND DEBUGGING ....................................3-8

• DVD PART SCHEMATIC DIAGRAMS ...................................................................................... 3-21

• PRINTED CIRCUIT DIAGRAM ................................................................................................. 3-29

❍ SECTION 4. EXPLODED VIEWS

• CABINET AND MAIN FRAME SECTION.................................................................................... 4-1

❍ SECTION 5. SPEAKER PART

• SPEAKER PART

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5-1

❍ SECTION 6. REPLACEMENT PARTS LIST

• REPLACEMENT PARTS LIST

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6-1

❏ 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.

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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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❏

AUDIO PART ELECTRICAL TROUBLESHOOTING GUIDE

VKK PART

Does DC - 33V appear at

PN301 pin .

Check the -27V of ZD901(-)

Check the Q902 TURN ON

Check the -277VLower of

C918(-)

Replace the Q902

Replace the D908, D909

Refer to power

Troubleshooting

YES

P-SENS PART

Does +5V appear at ZD900?

Check the pattern of

IC301 pin .

Check the waveform

of D907 (+).

Check the R901 and Replace

ZD 900

Replace the D907

YES

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POWER CIRCUIT

Check the Fuse

Check the DC output

of C732(+), C731(-)

Check the DC

Output of IC712, IC751

Replace the Fuse

Check the 1.5V AC output of D701

Replace the D701

Replace the Transformer

YES

NO NO

MUTING CIRCUIT (MUTE)

Dose “High” appear at

Q701, Q702, Q703, Q751,

Q752 “B”

check the “Low” of Q701,

Q702, Q703, Q751, Q752 “C”

MUTE

Check the IC203 Troubleshooting

(ONLY Q201/Q251)

Check the “High” of Q704, Q705,

Q706 “E” (ONLY Q701/Q751)

Replace the Q704, Q705, Q706

Replace the TR

Refer to IC 301

Troubleshooting

YES

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AUDIO ABNORMAL

Check the output of

IC701, IC702, IC703 Pin 2, 4

Check the connecting to

speaker

Check the FUNCTION input

terminal

Check the input of IC701,

IC702, IC703, pin7, 11

Check the 12V output of

IC602, IC601

Check the 12V output of

IC704

YES

FUNCTION MODE AUDIO ABNORMAL

TAPE

Check the signal input

of IC601 pin6, 23

Refer to “IC201 Troubleshooting”

AUX

Chekc the signal input of IC600,

5, 24

Check the signal input of JK400

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Check the signal input of IC601

3, 26

Check the signal input of PN704

pin11, 13, 15, 17, 19

Check the signal input of IC601 pin4, 25

Refer to “TUNER PACK Troubleshooting”

TUNER

IC301 TROUBLESHOOTING

Check the power supplied to IC301

17, 46, 72, 90?

Refer to “Power Circuit Troubleshooting”

Check the P-SENS

Replace the X301

Check the RESET circuit

Check the P-SENS “High” of IC301 pin26

Check the oscillation of X301

When power supplying to IC301 pin12.

(Low ➞ High)

Replace the IC301

YES

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Refer to “IC301

Troubleshooting”

IC601 TROUBLESHOOTING

IC602 TROUBLESHOOTING

Refer to “Power Circuit Troubleshooting”

Check the Data of IC301 pin87, 88

(CD ➞ TAPE FUNCTION)

Refer to power Troubleshooting

Check the Data of IC301 pin 85, 86

Check the patter of IC301 & IC602

Replace the

IC601

Check the pattern of

IC301 & IC601

Check the power supplied

to IC601 pin1

Check the CLK Data of IC601 pin14, 15

Check the FUNCTION SELECTOR

END

Check the Power supplied to IC602 pin 1

Check the CLK Data of IC602 pin9, 10

Replace the IC602

YES

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TUNER PACK TROUBLESHOOTING

Check the 9V of PN602 pin2

Check the GND of PN602 pin 4, 10

Check the pattern

Check the DC of C670

Check the power

YES

PLAY

Check the VCC supplying to IC201 pin4

Refer to “Power Circuit

Troubleshooting”

Check the Deck Mecha

Replace the Deck

Mecha.

Replace the IC201

Check the signal output of IC201 pin3, 6

Check the “LOW” of Q201, Q251, “B”

YES

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REC (Q252, Q202 ON / R273, R223 HIGH)

Check signal supplied to IC203 pin2, 8 ?

Check the output of IC203 pin3, 7

Check the “output” of L201 pin5

Refer to “power circuit Troubleshooting”

Check the power

supplying to C227(+)

Check the oscillation

of Q204, “E”

Check the signal of

R212, R262

Check the Pattern

Check the Vcc power of IC203 Pin6

Check the oscillation of L201 pin 1, 3

Replace the DECK

Check the “Low” of Q202,

Q252 “B”

Replace the Q202, Q252

Check the “Low” of

IC501 pin9

Refer to

“Power Circuit

Troubleshooting”

Check the 0.6V of

Q205 “B”

Replace the L201

YES

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• POWER P.C. BOARD (SOLDER SIDE)

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1. Power check flow

SECTION 3. DVD PART ELECTRICAL

TROUBLESHOOTING GUIDE

2. Test & debug flow

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+ 37 hidden pages