LG LX-M150A User manual

MICRO COMPONENT
SYSTEM
MODEL : LX-M150A/D, LXS-M150
SERVICE MANUALMODEL: LX-M150A/D, LXS-M150LG Electronics Inc.

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SECTION 1. GENERAL
• SERVICING PRECAUTIONS .....................................................................................................1-2
• ESD PRECAUTIONS..................................................................................................................1-4
• SPECIFICATION.........................................................................................................................1-5
SECTION 2. ELECTRICAL
• ADJUSTMENTS ..........................................................................................................................2-1
• WAVEFORMS OF MAJOR CHECK POINT................................................................................2-2
• TROUBLESHOOTING ................................................................................................................2-4
• BLOCK DIAGRAM ....................................................................................................................2-19
• SCHEMATIC DIAGRAMS .........................................................................................................2-21
• WIRING DIAGRAM ...................................................................................................................2-29
• PRINTED CIRCUIT DIAGRAMS...............................................................................................2-31
• INTERNAL BLOCK DIAGRAM OF ICs .....................................................................................2-39
SECTION 3. EXPLODED VIEWS
• CABINET AND MAIN FRAME SECTION....................................................................................3-1
SECTION 4. SPEAKER .......................................................................................................4-1
SECTION 5. REPLACEMENT PARTS LIST
• REPLACEMENT PARTS LIST ....................................................................................................5-1
[CONTENTS]

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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

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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 -
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.
ESD PRECAUTIONS

- 1-5 -
SPECIFICATIONS
SECTION MODEL LX-M150A/D/X
Power supply Refer to the back panel of the unit
General Power consumption 20W
Mass 3kg
External dimensions(WxHxD) 146x238x251mm
Frequency Response 40 ~ 18000Hz
CD Signal-to-noise ratio 60dB
Dynamic Range 60dB
Tuning Range 87.5 ~ 108.0MHz or 65 ~74MHz, 87.5 ~ 108.0MHz
FM Intermediate Frequency 10.7MHz
Signal-to-noise ratio 55/50dB(Mono/Stereo)
Frequncy Response 60 ~ 1000Hz
Tuning Range 522 ~ 1611kHz or 530 ~ 1610kHz
AM Intermediate Frequency 450kHz
Signal-to-noise ratio 35dB
Frequency Response 10 ~ 1800Hz
Output Power 5W + 5W
AMP T.H.D 0.5%
Frequncy Response 60 ~ 20000Hz
Signal-to-noise ratio 60dB
Tape Speed 4.75cm/sec
Wow Flutter 0.3%(MTT-111, JIS-WTD)
F.F/REW time 120sec(C-60)
TAPE Frequency Response 250 ~ 8000 Hz
Signal-to-noise ratio 40dB(P/B)/38dB(R/P)
Channel Separation 32dB(P/B)/30dB(R/P)
Erase Ratio 50dB(MTT-5511)
MODEL LXS-M150
Type 1Way 1 Speaker
Impedance 4Ω
Frequency Response 100 ~ 18000Hz
SPEAKER Sound Pressure Level 86dB/W(1m)
Rated Input Power 5W
Max.Input Power 10W
Net Dimension(WxHxD) 146x238x185mm
Net weight 1.4kg
TUNER
NOTE : Specification are subject to change without notice in the course of product improvement.

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MEMO

- 2-1 -
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.
TAPE DECK ADJUSTMENT
1. AZIMUTH ADJUSTMENT
2. RECORD BIAS ADJUSTMENT
ADJUSTMENTS
SECTION 2. ELECTRICAL
Deck Mode Test Tape Test Point Adjustment Adjust for
Palyback MTT-114 Speaker Out DECK Screw Maximum
Azimuth Screw
Deck Mode Test Point Adjustment Adjust for
DC Voltage Check point TP1, TP2 DECK Screw 0V ± 50mV

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WAVEFORMS OF MAJOR CHECK POINT

- 2-3 -
#4. SPINDLE DRIVE AND MOTOR WAVEFORM
(IC503 pin6, 12) when TOC reading
#5. TRACK DRIVE AND MOTOR WAVEFORM
(TP560, IC503 pin23) during normal play
#6. RF, TRACKING AND FOCUS ERROR WAVEFORM
(IC502 pin8, 21, 23) during normal play

- 2-4 -
• CD PART
TROUBLESHOOTING
CD FUNC. ON
CLOSE CHECK
READING OK CHECK
OK
CONNECTOR CHECK (PN508)
CHECK AN22004 (IC502)
CHECK MN6627933CG (IC501)
CHECK SA5810FP (IC503)
CHECK PICKUP MOVEMENT
CONNECTOR CHECK(PN501, PN503)
CHECK MICOM INTERFACE CIRCUIT(PN507)
CN502 CHECK
CHECK MICOM INTERFACE CIRCUIT(PN507)
CHECK POWER SUPPLY CIRCUIT(PN508)
CONNECTOR CHECK (PN508, PN507, PN503, PN501)
AUDIO
OUTPUT CHECK
“READING ”
DISPLAY CHECK

- 2-5 -
• “READING” DISPLAY CHECK
(= ONLY “CD” DISPLAY)
CONNECTOR LOCKING CHECK
(PN508, PN507, PN503, PN501 )
CHECK VOLTAGE THE PIN 2 OF IC505
IC505 PIN2 : 3.3V
DEFECTIVE CONNECTOR OR
MAIN POWER SUPPLAY
DEFECTIVE IC505
DEFECTIVE MICOM (IC300)
OR PN507
DEFECTIVE MICOM (IC300)
PIN97 OR PN507
CHECK RESET SIGNAL OF PN507
PN507 PIN7 : 5V
END
CHECK POWER SUPPLY
PORT( PN508, PN507)
PN508 PIN 8 = 6.2V, PIN 7 = 5V
PN507 PIN 1 = 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

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• READING OK CHECK
(= “NO DISC” DISPLAY)
CONNECTOR LOCKING
CHECK(PN501, CN503)
DOES SLED MOVE?
CHECK CN503 PIN 3, 4(SL+, SL-)
CHECK PN501 PIN 13, 16
(FA-, FA+)
CHECK PN501 PIN 10(LD)
CHECK CN503 PIN
5, 6(SP+, SP-)
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
DOES LASER LIGHT?
DOES SPINDLE ROTATE?
IS READING OK?
CHECK PN501 PIN 14, 15
(TA-, TA+)
DOES LENSE MOVE?
(= UP & DOWN)

- 2-7 -
• READING OK CHECK #A
(= “NO DISC” DISPLAY)
DOES SL+ WAVEFORM APPEAR AT
(IC503 PIN14 AND CN503 PIN3)
WAVEFORM #2
SLED MOTOR WAVE
DOES SLIN WAVEFORM
APPEAR AT
(IC503 PIN 5)
WAVEFORM #2
SLED DRIVE WAVE
DEFECTIVE IC501
DEFECTIVE IC503
DEFECTIVE CN503
CONNECTOR
DEFECTIVE PICKUP
SLED MOTOR
CHECK CN503 CONNECTOR LINE
END

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

- 2-9 -
• READING OK CHECK #C
(= “NO DISC” DISPLAY)
IS VOLTAGE 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 IC502K
LASER CONTROL
VOLTAGE CHECK
CHECK PN501 CONNECTOR LINE
DEFECTIVE IC505
DEFECTIVE IC502
DEFECTIVE Q501 OR
D502
DEFECTIVE PN501
CONNECTOR
DEFECTIVE PICKUP
LASER PART
END

- 2-10 -
• READING OK CHECK #D
(= “NO DISC” DISPLAY)
DOES SP+ WAVEFORM APPEAR
AT (IC503 PIN12 AND PN503 PIN6)
WAVEFORM #4
SPINDLE MOTOR DRIVE WAVE
DOES SPIN WAVEFORM
APPEAR AT
(IC503 PIN 6)
WAVEFORM #4
SPINDLE DRIVE WAVE
DEFECTIVE IC501
DEFECTIVE IC503
DEFECTIVE PN503
CONNECTOR
DEFECTIVE PICKUP
SPINDLE MOTOR
CHECK PN503 CONNECTOR LINE
END

- 2-11 -
• READING OK CHECK # E
(= “NO DISC” DISPLAY)
DOES TA+ WAVEFORM APPEAR
AT (IC503 PIN17 AND PN503 PIN15)
WAVEFORM #5
TRACKING COIL DRIVE WAVE
DOES TAIN- WAVEFORM
APPEAR AT
(IC503 PIN 23)
WAVEFORM #5
TRACKING DRIVE WAVE
DEFECTIVE IC501
DEFECTIVE IC503
DEFECTIVE PN503
CONNECTOR
DEFECTIVE PICKUP OR
IC502
DEFECTIVE PICKUP OR
IC502
DEFECTIVE IC501
CHECK PN503 CONNECTOR LINE
DOES ARF SIGNAL APPEAR?
(IC502 PORT 8)
WAVEFORM #6
DOES FE, TE SIGNAL APPEAR?
(IC502 PORT FE:23, TE:21)
WAVEFORM #6
END

- 2-12 -
• AUDIO PART

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