LG LX-E330A Manuale utente
- 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............................................................................... 2-6
• BLOCK DIAGRAM.................................................................................................................... 2-15
• SCHEMATIC DIAGRAMS ........................................................................................................ 2-17
• WIREING DIAGRAM ................................................................................................................ 2-23
• PRINTED CIRCUIT BOARD DIAGRAMS ................................................................................ 2-25
• INTERNAL BLOCK DIAGRAM OF ICs .................................................................................... 2-35
❍ 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.
- 1-2 -
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.
- 1-3 -
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.
- 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 -
Turn power on.
Is power on?
Does initial
read work?
Does it play?
Does it output
audio?
Check power supply circuit.
PN808 PIN1, 12V
PN808 PIN2, 6.2V
PN808 PIN3, 5V
IC803 PIN2, 3.3V
Check the connector PN801,
PN802, PN803, PN807, PN808.
Check the tracking servo.
Check the PN808 PIN8, 9.
OK
NO
YES
YES
YES
NO
NO
NO
NO
NONO
Check the DISK circuit.
Check the Laser.
Check the focus circuit.
Check the TRAKING servo.
NO
NO
❏ TROUBLESHOOTING
• CD PART
- 2-3 -
A
B
2V
5V
0V
5V
0V
1V
2V
1.2V
0V
0.8V
FAILS TO INITIAL READ
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Disc motor turns.
Does MD act?
Does RF waveform
appear? IC803 Pin3
Check the Data transferred from
PN807 pin5 to CD DSP.
Check the Data transferred from
PN807 pin7 to MICOM.
Are SLOD voltage.
transmited in IC801 PIN23
(IC801 pin23)
Check the change of
SL +, SL - Voltage.
(IC802 pin 13, 14)
Defective connector PN802.
Do voltage N 807 PIN11(MM+), PIN
12 (MM-), PIN13 (SOL) change?
• Defective connection PN807.
• Check the MICOM.
• Defective connector
PN807.
• Defective MICOM.
•
Defective
connector PN807.
•
Defective IC801.
Defective IC801.
Defective IC802.
• Defective contact PN803.
• Defective PICK-UP.
Does laser light?
focus coil drive wareform.
TRACKING ERROR wareform.
Is rotation normal?
•
Defective IC801.
•
Defective PICK-UP.
Is there no dropout of RF signal?
Does FA+ waveform appear at
IC802 pin15?
Does TE waveform appear at
IC801 pin15?
- 2-4 -
NO
NO
NO
NO
NO
NO
Laser does not light.
Is “2.5V” applied to pin80
of IC801?
Is power supplied to laser Q801?
(Q801 collector: about 1.8V)
Does laser current flow?
(R808’s voltage are 1.0V)
Is data transferred from
MICOM IC ?
Does voltage appear at IC
802 pin13, 14?
Defective MICOM.
Defective MICOM.
Defective connector.
Defective IC801, 802 .
Defective slide motor and/or
connector.
Defective LMT SW and/or
connector.
Defective Q 801 and/or laser.
Defective laser and/or
connector.
Did pickup return to
innermost circular?
Does it stop at inner pick
circular after shift?
Is defect output from LM
SW applied to pin 2 of
PN803?
R808 »1.0V
R808 «1.0V
YES
YES
YES
YES
OPEN CLOSE
YES
YES
YES
YES
YES
YES
- 2-5 -
B
NO
NO
NO
NO
NO
YES
YES
YES
YES
Laser lights
Does lens move up/down? Check the signal of FOCUS
SEARCH.
(IC801 Pin 21)
Chekc the signal of PN801
pin 13, 16.
Does FE signal appear?
(IC801 pin 13)
Does DRF signal appear?
(IC801 pin67)
Defective IC801.
Defective IC802.
Open activator and/or
connector.
Defective IC801.
Degraded laser diode
Defective PICK-UP
- 2-6 -
(CH1)
(CH2)
❏ WAVEFORMS OF MAJOR CHECK POINT
1. HF signal (RF signal ) waveform
(IC801 pin3) during normal play
2. EFM signal (IC801 pin 3)waveform
during Normal Play
3. Focus coil drive waveform(IC802 pin13)
• When focus search failed or there is no disc on the tray
• Focus coil drive waveform(FDO: IC801 pin21) and
DRF(IC801 pin67) when focus search is accomplished
4. Tracking coil drive waveform and TE during track
traverse
(1) When time division is 20mS/Div.1V/Div.
(3) When time division is 0.5nS/div.
(During backward Track Traverse)
5. Feed motor drive waveform(IC 802 pin14)
During normal play
CH1 : FOCUS COIL DRIVE
SIGNAL 2V/Div.
CH2 : DRF
CH1 : TRACKING COIL DRIVE
SIGNAL 2V/Div. (IC802 pin27)
CH2 : TRACKING ERROR(TE: IC801 pin15)
1V/Div.
(
(
(
CH1 : TRACKING COIL DRIVE (IC802 pin17)
SIGNAL 2V/Div.
CH2 : TRACKING ERROR (TE: IC802 pin15)
1V/Div.
(
CH1 : TRACKING COIL DRIVE (IC802 pin27)
CH2 : TRACKING ERROR (TE: IC801 pin15)
(
0.5V/Div.
500nS/Div.
(
1S/Div.
1V/Div.
(
1mS/Div.
1V/Div.
(
0.5V/Div.
5µS/Div.
(
2S/Div.
0.5V/Div.
OV
OV
OV
(CH1)
(CH2)
(CH1)
(CH2)
(CH2)
OV
OV
OV
OV
OV
OV
OV
OV
OV
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