LG LX-M240 D User manual

- 1-1 -
[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 ................................................................................................................ 2-31
• PRINTED CIRCUIT DIAGRAMS .............................................................................................. 2-33
• INTERNAL BLOCK DIAGRAM OF ICs .................................................................................... 2-42
❍ SECTION 3. EXPLODED VIEWS
• CABINET AND MAIN FRAME SECTION................................................................................... 3-1
• TAPE DECK MECHANISM: AUTOREVERSE DECK ................................................................. 3-3
• TAPE DECK MECHANISM: AUTOSTOP DECK(OPTIONAL).................................................... 3-5
• CD MECHANISM ......................................................................................................................... 3-7
❍ 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
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)
Resistor
(1 Mohm)
VOLUME KNOB
UP
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]
- 1-4 -
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
- 1-5 -

- 1-6 -
MEMO

- 2-1 -
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

- 2-2 -
❏ TROUBLESHOOTING
• CD PART
TURN ON CD
OPEN CLOSE CHECK
CONNECTOR CHECK ( PN508,PN507 )
CHECK POWER SUPPLY CIRCUIT( PN508 )
CHECK MICOM INTERFACE CIRCUIT( PN507 )
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
OK
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES

- 2-3 -
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)
NO
NO
NO
NO
YES
YES
YES

- 2-4 -
• “ 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
NO
NO
NO
NO
NO
YES
YES
YES
YESYES

- 2-5 -
• READING OK CHECK (= “NO DISC” DISPLAY)
A
AA
A
B
BB
B
C
CC
C
D
DD
D
E
EE
E
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 ?
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YESYES
YES
YES
YES

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

- 2-7 -
• READING OK CHECK #B (= “NO DISC” DISPLAY)
B
BB
B
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
NO
NO
NO
NO
NO
YES

- 2-8 -
• READING OK CHECK #C (= “NO DISC” DISPLAY)
C
CC
C
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
NO
NO
NO
NO
NO
NO
YES
YES

- 2-9 -
• READING OK CHECK #D (= “NO DISC” DISPLAY)
D
DD
D
CHECK PN503 CONNECTOR LINE
DEFECTIVE IC501
DEFECTIVE IC503
DEFECTIVE PN503
CONNECTOR
DEFECTIVE PICKUP
“SPINDLE MOTOR
NO
NO
NO
NO
NO
YES
YES
DOES SPIN WAVEFORM
APPEAR AT
( IC503 PIN 6)
WAVEFORM #4
SPINDLE DRIVE WAVE
DOES SP+ WAVEFORM APPEAR
AT ( IC503 PIN12 AND PN503 PIN6)
WAVEFORM #4
SPINDLE MOTOR DRIVE WAVE

- 2-10 -
• READING OK CHECK #E (= “NO DISC” DISPLAY)
E
EE
E
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
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
DEFECTIVE IC501
DEFECTIVE PN503
CONNECTOR
DEFECTIVE PICKUP OR
IC502
DEFECTIVE PICKUP OR
IC502
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO

- 2-11 -
❏ WAVEFORMS OF MAKOR CHECK POINT
#1 . MICOM INTERFACE WAVEFORM
(PN507 pin6, 8, 9, 1 0) during normal play
#2. SLED DRIVE AND MOTOR WAVEFORM
(IC503 pin5, 1 4) when focus search
#3. FOCUS DRIVE AND MOTOR WAVEFORM
(TP56 1 , IC503 pin 1 5)
- When focus search failed or there is no
disc on tray
- There is disc on tray and focus search
success

- 2-12 -
#4. SPINDLE DRIVE AND MOTOR WAVEFORM
(IC503 pin6, 1 2) when TOC reading
#5. TRACK DRIVE AND MOTOR WAVEFORM
(TP560, IC503 pin23) during normal play
#6. RF, TRACKING AND FOCUS ERROR WAVEFORM
(IC502 pin8, 2 1 , 23) during normal play

- 2-13 -
❏ AUDIO PART
VKK PART
Does DC - 27V appear at
PN601 pin .
Check the pattern of FRONT
PCB ASS’Y
Check the DC -34V of C928(-)
Check the DC -27V of
ZD 902(-)
Check the DC -27V of
Q901 “E”
Check the PATTERN
Replace the D936
Replace the ZD902
Replace the Q901
YES
YES
YES
YES
NO
NO
NO
NO
P-SENS PART
Does +5V appear at ZD901?
Check the pattern of
IC301 pin .
Check the waveform
of D937 (+).
Replace ZD901.
Replace the D937
YES
YES
NO
NO
26
16

- 2-14 -
POWER CIRCUIT
Check the Fuse
Check the DC output
of C923(+)
Check the DC 12V
Output of IC901
Check the DC 6.2V
output of IC902
Check the DC 12V
Output of IC903
Check the 5.6V of Q604 “C”
(CD FUNCTION)
END
Replace the Fuse
CHECK THE AC VOLTAGE
OF CN901 pin 5, 6
Check the DC VOLTAGE of
D939(+)
Replace the Q501
Replace the D925, D926,
D927, D928
Replace the IC902
Check DC VOLTAGE OF
D930(+)
Check the “LOW”of
IC501 pin8
Check the “High”of Q605“B”
Replace the Q604
Replace the IC902
Replace the Transformer
Replace the D939
Replace the D930
Replace the IC501
Check the “High”of
IC501 pin4
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO