LG OM4560 User manual

SERVICE MANUAL
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
Internal Use Only
APRIL, 2016
MODEL: OM4560
MODEL: OM4560
MINI HI-FI AUDIO
P/NO : AFN77483237

CONTENTS
SECTION 1 ........ GENERAL
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
HIDDEN KEY MODE ......................................................................................................................................... 1-6
SERVICE INFORMATION FOR EEPROM........................................................................................................ 1-7
PROGRAM DOWNLOAD & UPDATE GUIDE.................................................................................................. 1-8
1. MCS PROGRAM....................................................................................................................................... 1-8
2. EQ PROGRAM ......................................................................................................................................... 1-9
SPECIFICATIONS ........................................................................................................................................... 1-10
1-2

1-3
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 cot-
ton 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
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 magne-
tism 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 M)
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.
Resistor
(1 M)Conductive
Sheet
Resistor
(1 M)
Armband
1-4

1-5
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

1-6
HIDDEN KEY MODE
Push both Front key and RCU key to activate it for 5 seconds.
1. Disc Lock On/Off (CD Function Only Active)
Front Key : STOP
RCU Key : STOP
2. Check Version and Option code
Front Key : STOP
RCU Key : PLAY/PAUSE
You can change [Audio MCU Version CD Controller Version EEPROM Option] by SKIP+/-.
3. Clear EEPROM
Front Key : STOP
RCU Key : 
4. Edit EEPROM
Front Key : STOP
RCU Key : 
You can change the digit of option by SKIP+/-.
You can edit 0~f by REPEAT or PLAY/PAUSE key.
5. Bluetooth DUT
Front Key : POWER
RCU Key : POWER
Block by network provision BT Auto Power On Disable / Enable.(Bluetooth model only)
6. Power Disc Lock On/Off (CD Function Only Active)
Front Key : STOP
RCU Key : EQ or FRONT(CD) OPEN
7. Amp Clip On/Off
Front Key : STOP
RCU Key : MUTE
Amp Clip Mode Change (Amp Clip On Amp Clip Off Level Down display).

POWER ON
POWER ON
Press Remote control (STOP) key
Remote control ‘|’ Key Button and Front ‘STOP’ Key Button
push same timing during 5 seconds.
Remote control ‘|’ Key Button and Front ‘STOP’ Key Button
push same timing.
FLD no disc status or AUX status.
FLD ‘write ok’
FLD ‘OP-0….
FLD ‘E2P CLR’
Remote Control ‘|’ or ‘|’ can be moved by using the Key Each option
‘Repeat’(+ Value) or ‘STOP’(- Value) using the Key Value of options
to change the code there.
Completed
1-7
SERVICE INFORMATION FOR EEPROM

1. MCS PROGRAM
Download program file name must be HG640_FW_OM4560_DATE.bin
If security program (Water Wall) is activated on your PC, you must save the file to the USB storage
device and disable the security software, then download the file to your set.
Caution: When downloading the file, you should neither unplug the USB device, change to the other
function, nor power off the device. USB device must be unplugged when the downloading
process is completed.
ON VFD DISPLAY SCREEN
NO USB
Insert USB device at USB function.
SEARCH

FIRMWARE

FINISH

POWER OFF AUTOMATICALLY When completed, remove USB device.
1-8
PROGRAM DOWNLOAD & UPDATE GUIDE

2. EQ PROGRAM
Download program file name must be EQ_PRG_OM4560_***.BIN
If security program (Water Wall) is activated on your PC, you must save the file to the USB storage
device and disable the security software, then download the file to your set.
Caution: When downloading the file, you should neither unplug the USB device, change to the other
function, nor power off the device. USB device must be unplugged when the downloading
process is completed.
ON VFD DISPLAY SCREEN
NO USB
Insert USB device at USB function.
SEARCH

FIRMWARE

FINISH

POWER OFF AUTOMATICALLY When completed, remove USB device.
1-9

SPECIFICATIONS
1-10
• GENERAL
Power requirements Refer to the main label.
Power consumption Refer to the main label.
Networked standby : 0.5 W (If all network ports are activated.)
Dimensions (W x H x D) Approx. 451.5 mm x 311 mm x 302.5 mm
Net Weight (Approx.) Approx. 7.5 kg
Operating temperature 5 °C to 35 °C
Operating humidity 5 % to 90 %
• INPUTS / OUTPUTS
Analog audio in (AUX IN) 2.0 Vrms (1 kHz, 0 dB), 600 Ω, RCA jack (L, R)
Analog audio out (AUX OUT) 2.0 Vrms (1 kHz, 0 dB), 600 Ω, RCA jack (L, R)
Microphone Sensitivity 15 mV (1 kHz), 6.3 mm jack x 1
• TUNER
FM Tuning Range 87.5 to 108.0 MHz or 87.50 to 108.00 MHz
• AMPLIFIER (RMS OUTPUT POWER)
Total 220 W x 1 (3 Ωat 1 kHz, 20 % THD)
• SYSTEM
Frequency Response 80 Hz to 20 kHz
Signal-to-noise ratio More than 75 dB (1 kHz)
Dynamic range More than 80 dB
Bus Power Supply (USB) 5 V 500 mA
• Design and specifications are subject to change without notice.

SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
EXPLODED VIEWS ........................................................................................................................................... 2-3
1. CABINET AND MAIN FRAME SECTION ................................................................................................. 2-3
2. DECK MECHANISM SECTION (DM19AB) .............................................................................................. 2-5
3. PACKING ACCESSORY SECTION ......................................................................................................... 2-7
2-1

2-2

C
B
A
H
D
E
F
L
L
D
K
I
K
I
J
F
G
J
A
B
C
E
A46
464
464
464
A47
521
521
464
A49
A48
A43
464
261
522
260 266
464
250
464
464
464
464
522
A53
261
CABLE5
CABLE2
CABLE3
CABLE4
CABLE1
A50
262
H
300
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION
NOTES) THE EXCLAMATION POINT WITHIN AN
EQUILATERAL TRIANGLE IS INTENDED
TO ALERT THE SERVICE PERSONNEL
TO THE PRESENCE OF IMPORTANT
SAFETY INFORMATION IN SERVICE
LITERATURE.

1439
A001
1002
1043
A005
1016
1013 1015
1020
1439
1018
1019
1012
A006
1045
1026
1049
1437
1437
1024
1024
1024
1024
1437
1005 1001
1003 1004
1011
1030
2. DECK MECHANISM SECTION (DM19AB)

3. PACKING ACCESSORY SECTION
900 Remote Control
808 Battery
825 FM Wire Antenna
802 Box
801 Owner’s Manual
804 Bag
803 Packing
803A Packing

SECTION 3 ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER ............................................................................................................................................ 3-2
2. NO BOOTING WHEN POWER ON THE SET........................................................................................ 3-4
3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET..................................................................... 3-5
4. NO OPERATION OF MD........................................................................................................................ 3-6
5. NO SOUND........................................................................................................................................... 3-11
6. PROTECTION....................................................................................................................................... 3-16
ELECTRICAL TROUBLESHOOTING GUIDE................................................................................................. 3-19
1. POWER (SMPS) ................................................................................................................................... 3-19
2. MCS PART CHECK.............................................................................................................................. 3-22
3. IC503(MX25L3235E) CHECK............................................................................................................... 3-22
4. VFD DISPLAY CHECK ......................................................................................................................... 3-23
5. PWM MODULATION CHECK............................................................................................................... 3-24
6. POWER AMP PART CHECK ............................................................................................................... 3-25
7. TUNER / AUX FUNCTION CHECK...................................................................................................... 3-26
8. TUNER FUNCTION CHECK................................................................................................................. 3-27
9. CD FUNCTION CHECK........................................................................................................................ 3-28
10. SINGLE USB FUNCTION..................................................................................................................... 3-29
WAVEFORMS OF MAJOR CHECK POINT.................................................................................................... 3-30
1. SDRAM ................................................................................................................................................. 3-30
2. SERVO.................................................................................................................................................. 3-30
3. AUDIO PATH ........................................................................................................................................ 3-30
4. USB....................................................................................................................................................... 3-30
WIRING DIAGRAM.......................................................................................................................................... 3-31
BLOCK DIAGRAMS ........................................................................................................................................ 3-33
1. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-33
2. SMPS BLOCK DIAGRAM..................................................................................................................... 3-35
3. AUDIO PATH BLOCK DIAGRAM ......................................................................................................... 3-37
4. POWER BLOCK DIAGRAM ................................................................................................................. 3-39
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-41
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-41
2. MAIN - DSP CIRCUIT........................................................................................................................... 3-43
3. MAIN - RF SERVO CIRCUIT DIAGRAM.............................................................................................. 3-45
4. MAIN - POWER DIAGRAM .................................................................................................................. 3-47
5. MAIN - AMP CIRCUIT DIAGRAM......................................................................................................... 3-49
6. MAIN - ANALOG INPUT CIRCUIT DIAGRAM ..................................................................................... 3-51
7. FRONT - VFD CIRCUIT DIAGRAM...................................................................................................... 3-53
8. JACK - MIC JACK CIRCUIT DIAGRAM ............................................................................................... 3-55
9. SPEAKER LED DISPLAY CIRCUIT DIAGRAM ................................................................................... 3-57
CIRCUIT VOLTAGE CHART........................................................................................................................... 3-59
1. ICs......................................................................................................................................................... 3-59
2. CAPACITORS....................................................................................................................................... 3-60
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-61
1. SMPS P.C.BOARD ............................................................................................................................... 3-61
2. MAIN P.C.BOARD ................................................................................................................................ 3-63
3. FRONT P. C. BOARD........................................................................................................................... 3-65
4. JACK P. C. BOARD .............................................................................................................................. 3-67
5. SPEAKER LED DISPLAY P. C. BOARD.............................................................................................. 3-67
3-1

3-2
ONE POINT REPAIR GUIDE
1. NO POWER
If the unit doesn’t work by no power problem, repair the set according to the following guide.
1-1. FUSE & BRIDGE DIODE
1-1-1. Solution
Please check and replace F901, BD901, TH901 on SMPS board.
1-1-2. How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check if the bridge diode BD901 is short-circuit by over current with a digital multi meter.
3) Check if the NTC thermistor TH901 is normal or open.
1-1-3. Service hint (Any picture/ Remark)
< F901 >
If F901 is not short-circuit,
replace it with a same
specifications one.
< TH901 >
If TH901 is open,
replace it with a new one.
< BD901 >
If BD901 is short-circuit,
replace it with a new one.

3-3
ONE POINT REPAIR GUIDE
NO POWER
If the unit doesn’t work by no power problem, repair the set according to the following guide.
1-2. D951
1-2-1. Solution
Please check and replace D951 on SMPS board.
1-2-2. How to troubleshoot (Countermeasure)
1) Check the anode-cathod voltage of D951 with a digital multi-meter, it is normally 0.2 ~ 0.3 V.
 If it doesn’t have any voltage, it’s destroyed. Replace it with a new one.
1-2-3. Service hint (Any picture/ Remark)
< SMPS schematic diagram >