MDT355
DVD Mini Hi-Fi System
SERVICE MANUAL
MODEL: MDT355(MDS355V/MDS355W)
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
MODEL: MDT355(MDS355V/MDS355W)SERVICE MANUAL
P/NO : AFN75496339 JUNE, 2011
Website http://biz.lgservice.com
Internal Use Only
CONTENTS
SECTION 1 ........ SUMMARY
SECTION 2 ........ CABINET & MAIN CHASSIS
SECTION 3 ........ ELECTRICAL
SECTION 4 ........ REPLACEMENT PARTS LIST
1-1
SECTION 1
SUMMARY
CONTENTS
SERVICING PRECAUTIONS ................................................................................................................... 1-3
ESD PRECAUTIONS .................................................................................................................................. 1-5
SERVICE INFORMATION FOR EEPROM .......................................................................................... 1-6
SOFTWARE UPGRADE PROCESS ..................................................................................................... 1-7
SPECIFICATIONS ....................................................................................................................................... 1-8
1-2
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 lens.
6) Never attempt to disassemble the pick-up.
Spring has 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.
Storage in conductive bag
Drop impact
NEVER look directly at the laser beam, and don’t allow
contact with fingers or other exposed skin.
Magnet
How to hold the pick-up
Conductive Sheet
Cotton swab
Pressure
Pressure
1-3
SERVICING PRECAUTIONS
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 or humidity is high, where strong magnet-
ism 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 (1 MΩ)
6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent stat-
ic 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.
Resistor
(1 MΩ)
Conductive
Sheet
Resistor
(1 MΩ)
Armband
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.
1-5
ESD PRECAUTIONS
POWER ON
FLD no disc status
Remote control ‘2’ + Front ‘STOP’
push same timing during 5s
FLD ‘OP-0….
Move to appropriate position
and make changes
with Rmc ‘skip, mode, play’ key.
Press STOP key
FLD ‘write ok’
Remote control ‘Fwd skip’ +
Front ‘STOP’ push same timing
FLD ‘E2P CLR’
Completed
NAME
OPT 0
OPT 1
OPT 2
OPT 3
OPT 4
OPT 5
OPT 6
OPT 7
OPT 8
OPT 9
DETECT NEW EEPROM
(OPTION EDIT SCREEN)
HEX
F5
00
A4
DD
00
09
81
20
50
00
1-6
SERVICE INFORMATION FOR EEPROM
Important Notice :
When ugrade the software running. Do not shunt down the power, it tmay damage the unit.
1. MICOM UPGRADE
1) Copy the software file into USB flash, as the file name is LG_MDT355__XXXXXXX.HE
2) Insert the USB flash into USB host.
3) Set Function to USB position.
Appear onto VFD
UPGRADE
4) After finish, Set will automatically power off.
2. FLASH MEMORY UPGRADE
1) Copy the software file into USB flash, As the file name is LG_MDT355__XXXXXXX.RO
2) Insert the USB flash into USB host.
3) Set Function to USB position.
Appear onto VFD
CODE 00
NO USB
4) Manual Power off and Power on is finish.
1-7
SOFTWARE UPGRADE PROCESS
SPECIFICATIONS
• GENERAL
Power supply Refer to main label.
Power consumption Refer to main label.
Net Weight 5.27 kg
External dimensions (W x H x D) ( 272 x 334 x 381 ) mm
Operating conditions Temperature 5 °C to 35 °C, Operation status: Horizontal
Operating humidity 5 % to 85 %
Laser Semiconductor laser, wavelength, 760 to 800 nm
• TUNER FM/AM [MW]
FM Tuning Range 87.5 to 108.0 MHz or 87.50 to 108.00 MHz
FM Intermediate Frequency 128 kHz
AM Tuning Range 522 to 1 620 kHz, 520 to 1 710 kHz or 522 to 1 710 kHz
AM Intermediate Frequency 45 kHz
• AMPLIFIER
Output Power Front : 100 W x 2
SUB Woofer : 150 W
• USB
Bus Power Supply (USB) DC 5 V 500 mA
USB Version USB 2.0 or USB 1.1
• CD
Frequency Response 40 to 20 000 Hz
Signal-to-noise ratio More than 60 dB
Dynamic range More than 50 dB
• TAPE
F.F/REW Time 120 sec (C-60)
Frequency Response 250 to 8 000 Hz
Signal to Noise Ratio 40 dB
Channel Separation 45 dB (P/B) / 40 dB (R/P)
Erase Ratio 50 dB (MTT-5511)
• SPEAKERS
FRONT SUBWOOFER
Speaker name MDS355V MDS355W
Type 2 Way 2 Speaker 1 Way 1 Speaker
Impedance 4 Ω 3 Ω
Rated Input Power 100 W 150 W
Max. Input Power 200 W 300 W
Net Dimensions (W x H x D) ( 222 x 342 x 276 ) mm ( 272 x 334 x 332 ) mm
Net Weight 4.75 kg 5.3 kg
1-8
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
EXPLODED VIEWS ..................................................................................................................................... 2-3
1. CABINET AND MAIN FRAME SECTION (MDT355) ................................................................................ 2-3
2. TAPE DECK MECHANISM SECTION ...................................................................................................... 2-5
3. SPEAKER SECTION ................................................................................................................................ 2-7
4. PACKING ACCESSORY SECTION ......................................................................................................... 2-9
2-1
2-2
MEMO
2-3 2-4
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION (MDT355)
O
MAIN
J
B
C
K
J
D
H
B
A
C
D
I
R
G
E
F
H
F
M
L
L
M
282
460
283
E
R
A
K
I
SMPS
O
G
N
N
Q
252
A00
269
270
268
A46
271
A47
300
273
272
A43
A49
459
256
255
251
258
257
254
253
261
265
262
259
A45
263L
264L
264R
266L
266R
267L
267R
A41L
A41A
A41R
263R
CABLE1
CABLE2
250
KEY2
MIC
KEY3
KEY1
VFD
LED
USB
274
A48
CABLE3
A01
A26
281
452
452
453
453
454
453
456
456
454
454
452
451
451
456
458
457
455
455
455
455
Q
2-5 2-6
2. TAPE DECK MECHANISM SECTION
A00
003
009
011
009
A02
015
007
001
037
A01
018
017
006
020
019
022
023
025
2-7
3-1. LEFT/RIGHT SPEAKER (MDS355V)
3. SPEAKER SECTION
A60
2-8
3-2. SUBWOOFER (MDS355W)
A90
2-9
Battery808
Remote controller900
Instruction Ass'y801
Packing803T
Packing
803B
Box802
Bag804
825 FM antenna
824 AM antenna
4. PACKING ACCESSORY SECTION
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