CONFIDENTIAL
SERVICE MANUAL
MODEL: OK75
MINI HI-FI SYSTEM
SERVICE MANUAL
MODEL: OK75
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
P/NO : AFN78511834
SEPTEMBER, 2018
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
CONTENTS
SECTION
SECTION
SECTION
SECTION
1 ........ GENERAL
2 ........ CABINET & MAIN CHASSIS
3 ........ ELECTRICAL
4 ........ MECHANISM (DM19D)
1-1
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
SECTION 1
SUMMARY
CONTENTS
SERVICING PRECAUTIONS ............................................................................................................................ 1-3
ESD PRECAUTIONS ......................................................................................................................................... 1-5
HIDDEN KEY MODE ......................................................................................................................................... 1-6
1. HIDDEN KEY MODE TABLE
2. HIDDEN KEY MODE DESCRIPTION
PROGRAM DOWNLOAD GUIDE...................................................................................................................... 1-7
FOTA UPDATE STEP USING BT APP .......................................................................................................... 1-10
SPECIFICATIONS ........................................................................................................................................... 1-12
1-2
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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.
Storage in conductive bag
Drop 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.
NEVER look directly at the laser beam, and don’t allow
contact with fingers or other exposed skin.
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.
Pressure
Magnet
Pressure
How to hold the pick-up
Cotton swab
Conductive Sheet
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.
1-3
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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 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 (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.
Armband
Resistor
(1 M)
Resistor
(1 M)
Conductive
Sheet
1-4
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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
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
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
HIDDEN KEY MODE
1. HIDDEN KEY MODE TABLE
HIDDEN MODE
ENTRANCE KEY(Audio)
EXIT KEY
Version Check
Front ‘Stop’ 
+ Remote Control Key ‘Play’ / for 5s
Remote Control Key ‘Play’ / for 1.5s
EEPROM INITIAL
Front ‘Stop’ 
+ Remote Control Key ‘
Auto exit
‘ for 5s
2. HIDDEN KEY MODE DESCRIPTION
2-1. Version Check
- Function : Version Check.
- Entrance Key : Front ‘Stop’ + Remote Control Key ‘Play’ for 5s.
- Exit Key : Remote Control Key ‘Play’ for 1.5s.
- Operation explanation : Remote Control Key OR .
VFD Display (Example)
Result
MCS Version
MICOM Version
OPTION Version
DEMO Version
DJ PRO Version
EQ Version
EQ Check sum Version
2-2. EEPROM Initial
- Function : Initialize data stored in EEPROM and BACKUP RAM data.
- Entrance Key : Front ‘Stop’ + Remote Control Key ‘ ‘ for 5s.
- Exit Key : Auto exit.
- Explanation : ‘E2P CLR’ is displayed on the VPD and turn off the power automatically.
1-6
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
PROGRAM DOWNLOAD GUIDE
1. AUDIO PROGRAM
Download program file name must be MICOM_OK75_YYMMDDX.HEX
If security program(Water Wall) is activated on PC, you must save the file to the USB storage device
and disable the security software, then download the file to your set.
Downloading file proceeds in the same way at USB1 function and USB2 function.
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
1) (Fast) Format USB device.
2) Copy Firmware file to USB device.
NO USB

Insert USB device at USB function.
SEARCH

MICOM UP

FINISH

AUTO POWER OFF
1-7
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2. CD PROGRAM
Download program file name must be HG790_OK75_YYMMDDX.bin
If security program(Water Wall) is activated on PC, you must save the file to the USB storage device
and disable the security software, then download the file to your set.
Downloading file proceeds in the same way at USB1 function and USB2 function.
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
1) (Fast) Format USB device.
2) Copy Firmware file to USB device.
NO USB

Insert USB device at USB function.
SEARCH

FIRMWARE

FINISH

AUTO POWER OFF
1-8
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3. EQ & DEMO PROGRAM
Download program file name must be EQ_DEMO_PRG_OK75_XXXX.BIN
If security program(Water Wall) is activated on PC, you must save the file to the USB storage device
and disable the security software, then download the file to your set.
Downloading file proceeds in the same way at USB1 function and USB2 function.
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
1) (Fast) Format USB device.
2) Copy Firmware file to USB device.
NO USB

Insert USB device at USB function.
SEARCH

EQDEMOUP

FINISH

AUTO POWER OFF
1-9
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
FOTA UPDATE STEP USING BT APP
Step1 : App connecting
Step2 : Device version info
(Check FW version)
After connecting the BT App with SET,
the user could find the “Device Version info” on
Setting tab.
When touch the “Device Version info” button,
user could find the current and latest SET
version on pop-up menu.
Step3 : Select update button
Step4 : Confirm update
When touch the “Update” button, user could
update the SET firmware using FOTA.
Select the OK button on the caution message.
1-10
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
Step5 : Download from CDN server
Step6 : Transfer FW
1st step is download from CDN server to
smart phone. The progress bar is displayed
on BT App.
After completed the download from server,
smart phone start to transfer the firmware to the
SET. The progress bar is displayed on BT App.
Step7 : FW Flash Writing
Step8 : FOTA complete
After completed the download from the smart
phone, the SET overwrite the firmware to flash
memory.
When finishing the flash memory writing, pop-up
message about finish is displayed and the SET
auto power off.
1-11
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
SPECIFICATIONS
 GENERAL
Power requirements
Power consumption
Dimensions (W x H x D)
Operating temperature
Operating humidity
Refer to the main label
Refer to the main label
Approx. 330 mm x 925
5 °C to 35 °C (41 °F to
60 %
 INPUTS
Digital audio in (OPTICAL IN)
Analog audio in (AUX IN)
Portable in (PORT. IN)
Microphone (MIC 1/2)
3.3 V (p-p), Optical jack x 1
2.0 Vrms (1 kHz, 0 dB), 600 Ω, RCA jack (L, R)
1.0 Vrms (3.5 mm stereo jack) x 1
Sensitivity 20 mV (1 kHz), 6.3 mm jack x 2
 TUNER
FM Tuning Range
87.5 to 108.0 MHz or 87.50 to 108.00 MHz
 SYSTEM
Frequency Response
Signal-to-noise ratio
Dynamic range
Bus Power Supply (USB)
Available Digital Input Audio Sampling Frequency
40 to 20,000 Hz
More than 75 dB
More than 80 dB
5V
500 mA
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz
 AMPLIFIER (RMS Output power)
Total output
HIGH
LOW
1,000 W RMS
295 W RMS × 2 (4 Ω at 1kHz, 10% THD)
410 W RMS (3 Ω at 200Hz, 10% THD)
on the unit.
on the unit.
mm x 360 mm
95 °F)
 Design and specifications are subject to change without notice.
1-12
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
DISASSEMBLY INSTRUCTIONS ..................................................................................................................... 2-2
EXPLODED VIEWS ........................................................................................................................................... 2-9
1. CABINET AND MAIN FRAME SECTION ................................................................................................. 2-9
2. DECK MECHANISM SECTION .............................................................................................................. 2-11
3. PACKING ACCESSORY SECTION ....................................................................................................... 2-13
2-1
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DISASSEMBLY INSTRUCTIONS
1) Remove the 6 screws.
Figure 1. Panel Side L/R disassembly - 1
2) Disassemble each of the two screws located inside the handle.
Figure 2. Panel Side L/R disassembly - 2
2-2
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3) Pull out Cover Side Assembly L/R in the backward direction.
Figure 3. Panel Side L/R disassembly - 3
4) Remove the 3 screws.
Figure 4. Panel Top disassembly - 1
2-3
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
5) Remove the two screws on the left and right sides.
Figure 5. Panel Top disassembly - 2
6) As shown in the figure, remove the Panel Top by pushing the front part and lifting the rear part.
Figure 6. Panel Top disassembly - 3
2-4
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
7) Remove the 9 screws on the Panel Rear.
Figure 7. Panel Rear disassembly
8) Bracket MD + Frame Main Screw 4 EA Disassembly
Figure 8. Main Set disassembly - 1
2-5
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
9) Remove the Set LED Connector / Speaker LED Connector / Speaker Network cable.
Figure 9. Main Set disassembly - 2
10) Power Cable Disconnection
Figure 10. Main Set disassembly - 3
2-6
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
11) Grasp both sides and pull upward to remove the assembly.
Figure 11. Main Set disassembly - 4
12) Complete removal of the Main Set.
Figure 12. After detaching the Main Set
2-7
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2-8
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
EXPLODED VIEWS
1. CABINET AND MAIN FRAME SECTION
D
CABLE2
260L
266
F
RMC
277
255
CABLE7
A42
CABLE6
BT
267
270
262
A41
A45
A51
J
K
269
A
265
A46
MAIN
256
CABLE6
CABLE3
B
I
C
H
D
B
A52
257
E
F
G
I
268
259
258
L
255
258
E
G
261
263
260R
L
A44
A
K
A00
H
CABLE5
SMPS
M
A50
M
A47
J
N
521
276
CN803
TOP
272
275
A60
521
274
273
251
251
272
521
272
C
N
300
CABLE1
2-9
2-10
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2. DECK MECHANISM SECTION (DM19D)
A00
1030
1049
1015
A005
2-11
2-12
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3. PACKING ACCESSORY SECTION
825 FM Wire Antenna
826 Filter, Ferrite Core
900 Remote Control
AM
AN
T
O/
M
R/
C
PO
WE
RC
OR
D
2-13
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2-14
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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 BOOTING (IN CD/USB FUNCTION) ................................................................................................ 3-6
5. NO OPERATION OF MD ........................................................................................................................ 3-9
6. NO SOUND ........................................................................................................................................... 3-14
ELECTRICAL TROUBLESHOOTING GUIDE................................................................................................. 3-23
1. POWER (SMPS) ................................................................................................................................... 3-23
2. MCS PART CHECK .............................................................................................................................. 3-26
3. FLD DISPLAY CHECK ......................................................................................................................... 3-27
4. PWM MODULATION CHECK ............................................................................................................... 3-28
5. POWER AMP PART CHECK ............................................................................................................... 3-29
6. TUNER / AUX FUNCTION CHECK ...................................................................................................... 3-30
7. TUNER FUNCTION CHECK................................................................................................................. 3-31
8. CD FUNCTION CHECK ........................................................................................................................ 3-32
9. DOUBLE USB FUNCTION ................................................................................................................... 3-33
WAVEFORMS OF MAJOR CHECK POINT.................................................................................................... 3-34
1. DSP (IC501) .......................................................................................................................................... 3-34
2. SDRAM (IC502) .................................................................................................................................... 3-35
3. SERVO (IC401)..................................................................................................................................... 3-36
4. MOTOR DRIVER (IC400) ..................................................................................................................... 3-37
5. ADC (IC301).......................................................................................................................................... 3-38
6. USB (CN502) ........................................................................................................................................ 3-38
7. BLUETOOTH (CN504).......................................................................................................................... 3-39
WIRING DIAGRAM .......................................................................................................................................... 3-41
BLOCK DIAGRAM .......................................................................................................................................... 3-43
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-45
1. IC VOLTAGE......................................................................................................................................... 3-45
2. FAN MOTOR VOLTAGE ...................................................................................................................... 3-46
3. SMPS CAPACITOR & ZENER DIODE ................................................................................................. 3-46
4. MAIN CAPACITOR ............................................................................................................................... 3-47
5. CONNECTOR VOLTAGE ..................................................................................................................... 3-48
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-53
1. SMPS P.C.BOARD DIAGRAM ............................................................................................................. 3-53
2. MAIN P.C.BOARD DIAGRAM .............................................................................................................. 3-57
3. TOP P.C.BOARD DIAGRAM ................................................................................................................ 3-61
4. JACK & RMC P.C.BOARD DIAGRAM ................................................................................................. 3-65
5. SPARKLE LED UP P.C.BOARD DIAGRAM ......................................................................................... 3-67
6. SPARKLE LED DOWN P.C.BOARD DIAGRAM .................................................................................. 3-67
7. X-FLASH LED UP LEFT P.C.BOARD DIAGRAM ................................................................................ 3-69
8. X-FLASH LED UP RIGHT P.C.BOARD DIAGRAM .............................................................................. 3-70
9. SPEAKER LED P.C.BOARD DIAGRAM .............................................................................................. 3-70
3-1
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
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/ THERMISTOR/ BRIDGE DIODE
1-1-1. Solution
Please check and replace F901, TH901 or TH903, BD901 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 NTC thermistor TH900 or TH903 is normal or open.
3) Check if the bridge diode BD901 is short-circuit by over current with a digital multi-meter.
1-1-3. Service hint (Any picture/ Remark)
!
F901
F H9 0 1
1
FH902
1
2
2
!
OTW2
RBU605M
BD901
1
2
2
1
L1
4
2
L1
1
3
HS900
1
1
1
2
L1
1
1
4
L1
4
4
LF902
LF902-*1
3
2
3
L2
3
4
L2
3
4
L2
2
CM902
LF901-*1
LF901
3
R903
L2
R900 1.5M
R902
100nF/275VAC
!
!
R901
!
T5AL/250V
(5A 250V)
CM901
PN901
GP390-02P-TS
470K
470K
470K
TP902
TP901
!
F901-*1
100nF/275VAC
VR901
T8AL/250V
OTW1
2
SVC681-14
NUTRAL
(WH/BL)
2
!
LIVE
(BK/BN)
OTW3
1
1
2
2
OTW4
Y_GND
!
CY900
!
C903-*3
270uF
C903-*2
180uF
TH901 DSC 3D-15 MSFC
CY901
TH903
!
TH902
GND
CY902
C903-*1
330uF
C903
330uF
< F901 >
If F901 is not short-circuit,
replace it with a same
specifications one.
<TH901 or TH903 >
If TH901 or TH903 is open,
replace it with a new one.
3-2
450V
< BD901 >
If BD901 is short-circuit,
replace it with a new one.
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO POWER
If the unit doesn’t work by no PVDD problem, repair the set according to the following guide.
1-2. FUSE/ FET
1-2-1. Solution
Please check and replace F901, Q901 on SMPS board.
1-2-2. How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) 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)
T903
C952
C953
2200uF/63V
2200uF/63V
47K
R960
47K
47K
R959
47K
1R9582
1R9572
C953-*1
16
2200uF/50V
3
C952-*1
!
S3
2200uF/50V
P2
P1
1
15
13
SF20A400HPI
3
1K
!
TP913
PC903
3B
2C
1
4
IC951
TP912
1E
R961
11
R962
N7
8
R953
11
9
TP914
Q950
KRC103S
C956
22K 1%
R951
TP910
1uF
R954
R972 1.5K
12
12
2.2K
7
7
1R9522
13
1K
N2
14
6
220
220
R971 2K
1.8K
1K
GND
15
P3
N4
4
R955
N6
N1
N3
N5
16
R956
D951
17
5
2
TP915
18
2
HS955
MED61841613
1
470P/1KVDC
GND
GND
2
S1
!
T904
C951
3A
2C
1N
ZD932 Z02W20VY
14
4
1
S2
MED62731209
HS952
25x15
2
3
TP911
< SMPS circuit >
3-3
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
2. NO BOOTING WHEN POWER ON THE SET
The set doesn’t work when press the power button on the top board or the remote control.
2-1. IC501
2-1-1. Solution
Replace IC501 on MAIN board.
2-1-2. How to troubleshoot (Countermeasure)
1) Check the +12 V (CN201) and 3.3 VA (IC202) in standby mode.
 If there is no 12 VA, check the SMPS and if doesn’t appear 3.3 VA, check IC202.
2) Check +12 V, +5.1 VA, 3.3 VA, DVCC_5V and DVCC_3.3V when power on the set.
- If the set doesn’t work regardless of what the KEY1 changes high to low while pressing the power button.
X500 and X501 work normally but, if you can not power on the set, replace the IC501 with a new one
on the main board.
2-1-3. Service hint (Any picture/ Remark)
X500
(24 MHz)
IC501
X501
(32.768 kHz)
< MAIN board top view >
R5B78
PWR_CTRL
< MAIN board bottom view >
3-4
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET
When power on the set, any icons or characters on VFD are not displayed.
3-1. VFD (VFD801)
3-1-1. Solution
Please check and replace VFD301 on TOP FRONT board.
3-1-2. How to troubleshoot (Countermeasure)
1) Check if VFD_12V, DVCC_3.3V and VCC_5V are output from SMPS to VFD via the main board.
2) Check if the IC501 outputs VFD_CLK, VFD_STB, and VFD_DAT to the top board.
3) Check if the VFD grid current amplifier circuit on the top board.
Check the drive signal to the transistor’s(Q801,2) base.
 If the control signals from VFD (DGND, VDD) isn’t output, replace VFD with a new one.
3-1-3. Service hint (Any picture/ Remark)
knuk
}mk†XY}
}jj†\}
k}jj†ZUZ}
}mk†jsr
}mk†z{i
}mk†kv
knuk
knukTX
}mk†XY}
}jj†\}
k}jj†ZUZ}
}mk†jsr
}mk†z{i
}mk†kv
knukTY
RZUZ}h
rl€Z
rl€Y
rl€X
tpj†}vs†h
tpj†}vs†i
zjyh†h
zjyh†i
mpsl†z†i
shukpunnlhy
rl€Z
rl€Y
rl€X
tpj†}†h
zjyh†i
mpsl†z†i
mpsl†z†h
mpsl†z†h
thpu†}†i
}m†XY}
YZ
k}†\UW}
YY
k}†\UW}
YX
k}†ZUZ}
YW
}mk†jsr
X`
}mk†z{i
X_
}mk†kh{
X^
knuk
nuk
X[
shukpunnlhy
XZ
rl€Z
XY
rl€Y
XX
rl€X
XW
tpj†}vs†h
`
tpj†}vs†i
_
zjyh{jo†h
^
zjyh{jo†i
]
mpsl†z†i
thpu†}†i
thpu†}†Th
thpu†}†h
knuk
\
R810(TP841)
Q801 Emitter
about
30 Vp-p
RZUZ}h
X\
tpj†}†i
zjyh†h
nuk
Y[
X]
RZUZ}h
shukpunnlhy
Y\
< Waveform of the grid current driver>
mpsl†z†h
[
thpu†}vs†i
Z
thpu†}vs†h
Y
GGGGGGnuk
X
nuk
ju_W[
knuk
< TOP FRONT circuit >
3-5
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
4. NO BOOTING (IN CD/USB FUNCTION)
After you turn on power key and displayed message in the following order (HELLO  VOL XX 
CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
4-1. NO DVCC_3.3V, 1.2 VA
4-1-1. Solution
Please check and replace IC202, IC205 on MAIN board.
4-1-2. How to troubleshoot (Countermeasure)
1) Check Voltage of IC202 pin3 on MAIN board.
 If IC202 pin3 (about 3.3 V) & pin1 Input 5.1 VA doesn’t come out, check IC201 & +12 V from SMPS board.
2) If IC201 pin2 (about 5.1 V) is normal, check voltage of IC205 pin3 (about 1.2 VA).
If IC205 pin3 (about 1.2 VA) doesn’t come out, check R218, R219, R221.
If there’s no defective component then replace IC205.
3) PWR_CTRL is high, check R214, R233 and if there’s no defective component then check DVCC_3.3V
short with GND.
PWR_CTRL (IC204 pin3) is high (about 3.2 V)
 If PWR_CTRL isn’t high, check pin D11 of IC501 & R512, R513
4) If PWR_CTRL is high, check R5B78 and if there’s no defective component then replace IC204.
4-1-3. Service hint (Any picture/ Remark)
IC201
IC203
IC202
IC205
< MAIN board top view >
IC204
< MAIN board bottom view >
3-6
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO BOOTING (IN CD/USB FUNCTION)
After you turn on power key and displayed message in the following order (HELLO  VOL XX 
CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
4-2. CRYSTAL (X500)
4-2-1. Solution
Replace X500 on MAIN board.
4-2-2. How to troubleshoot (Countermeasure)
1) If 3.3 VA & 1.2 VA is normal, check reset ‘High’ of IC501 pin T12 on MAIN board.
 If MAIN_RESET isn’t high, check MICOM (IC101) pin40.
2) If MAIN_RESET is high, check the soldering status of 24 MHz crystal (X500).
3) If the crystal (X500) doesn’t oscillate, check R5B4, R5B6, C5B2, C5B5 around crystal (X500).
 If there’s no defective component, then replace X500.
4-2-3. Service hint (Any picture/ Remark)
XI
X500
XO
IC501
X500
< Signal waveform >
< MAIN board top view >
3-7
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO BOOTING (IN CD/USB FUNCTION)
After you turn on power key and displayed message in the following order (HELLO  VOL XX 
CD or USB) on VFD, it will not display other message on VFD, and it will not boot-up normally.
4-3. SERIAL FLASH (IC503)
4-3-1. Solution
Please check and replace IC503 on MAIN board.
4-3-2. How to troubleshoot (Countermeasure)
1) If the crystal (X500) does oscillate, check serial flash (IC503) on MAIN board.
 Check pin8 (VCC), pin6 (CLK), pin1 (CS), pin2 (DO), pin5 (DI) of below waveform.
2) If pin1, 2, 5, 6 doesn’t come out, check registers (R5B72 ~ 5) of IC503.
 If registers of IC503 is OK, then replace IC503. (it need to download program.)
3) After change IC503, if It is still not below waveform, check IC501 (DSP IC).
4-3-3. Service hint (Any picture/ Remark)
VCC
CS#
CLK
IC503
DO
< Signal waveform >
< MAIN board bottom view >
3-8
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
5. NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD
disc if the servo motors in MD don’t work. This step is for checking the SPINDLE MOTOR among
them.
5-1. SPINDLE MOTOR
5-1-1. Solution
Replace IC400 on MAIN board.
5-1-2. How to troubleshoot (Countermeasure)
1) Check the SPDO signal from pin16 of IC401.
 If no signal, check DVCC_3.3V and X400.
2) Check the SPIN+ & SPIN- from IC400 to CN401 for driving SPINDLE motor. It is about 3.6 Vp-p.
 If no signal, check M_5 V for IC400.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
 If the spindle motor is sort-circuit or has any trouble, it can not rotate CD discs.
Please check the function after changing another MD.
5-1-3. Service hint (Any picture/ Remark)
IC400
SP+: pin17
SP-: pin18
IC401
< Waveform of SP- & SP+
for driving SPINDLE motor >
< MAIN board bottom view >
3-9
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD
disc if the servo motors in MD don’t work. This step is for checking the SLED MOTOR among
them.
5-2. SLED MOTOR
5-2-1. Solution
Replace IC400 on MAIN board.
5-2-2. How to troubleshoot (Countermeasure)
1) Check the SLDO signal from pin15 of IC401.
 If no signal, check DVCC_3.3V and X400.
2) Check the SPED+ & SLED- from IC400 to CN401 for driving SPINDLE motor. It is about 2.9 Vp-p.
 If no signal, check M_5 V for IC400.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
 If the spindle motor is sort-circuit or has any trouble, it can not rotate CD discs.
Please check the function after changing another MD.
5-2-3. Service hint (Any picture/ Remark)
SP+
IC400
SLED+: pin11
SLED-: pin12
SPIC401
< Waveform of SLED- & SLED+
for driving SLED motor >
< MAIN board bottom view >
3-10
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD
disc if the servo motors in MD don’t work. This step is for checking the TRAY OPEN / CLOSE
MOTOR among them.
5-3. TRAY OPEN/ CLOSE MOTOR
5-3-1. Solution
Replace IC400 on MAIN board.
5-3-2. How to troubleshoot (Countermeasure)
1) Check MOT_OPEN & MOT_CLOSE signals from pin P5, L4 of IC501 to IC400.
 If no signal, check M_5V to IC400.
2) Check LOAD± from IC400 to CN401 for driving the tray open / close motor. It is about 3.85 Vp-p.
 If no signal, check M_5V to IC400. If it has any trouble, replace it with a new one.
3) Check if the FFC cable is solidly connected between CN401 and MD.
4) Check the MD.
 If the tray motor is sort-circuit or has any trouble, it can not open or close the tray.
Please check the function after changing another MD.
5-3-3. Service hint (Any picture/ Remark)
M_CL: pin6
M_OP: pin7
LOLO+(RED)
IC400
LO+: pin9
LO-: pin10
IC401
MOT_OPEN
MOT_CLOSE
< Waveform
for driving tray open/ close motor >
< MAIN board bottom view >
3-11
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD
disc if the pickup module in MD doesn’t work. This step is for checking the LASER TRACKING
ACTUATOR.
5-4. LASER TRACKING ACTUATOR
5-4-1. Solution
Replace IC400 on MAIN board.
5-4-2. How to troubleshoot (Countermeasure)
The tracking actuator makes the laser beam be positioned in the center of a track on CD disc.
1) Check the TRD signal from pin14 of IC401.
 If no signal, check DVCC_3.3V and X400.
2) Check TR- & TR+ from IC400 to CN400 for driving the tracking actuator.
 If no signal, check M_5V for IC400.
3) Check if the FFC cable is solidly connected between CN400 and MD.
4) Check the MD.
 If the pickup module has any trouble, it can not move the laser beam on the left or right side.
Please check the function after changing another MD.
5-4-3. Service hint (Any picture/ Remark)
IC400
TR+: pin16
TR-: pin15
IC401
< MAIN board bottom view >
< Waveform of TR±
for driving tracking actuator >
3-12
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD
disc if the pickup module in MD doesn’t work. This step is for checking the LASER FOCUSING
ACTUATOR.
5-5. LASER FOCUSING ACTUATOR
5-5-1. Solution
Replace IC400 on MAIN board.
5-5-2. How to troubleshoot (Countermeasure)
The focusing actuator makes the laser beam keep a regular interval with the surface of a CD disc.
1) Check the FDO signal from pin13 of IC401.
 If no signal, check DVCC_3.3 and X400.
2) Check F- & F+ from IC400 to CN400 for driving the focusing actuator.
 If no signal, check M_5V for IC400.
3) Check if the FFC cable is solidly connected between CN400 and MD.
4) Check the MD.
 If the pickup module has any trouble, it can not move the laser beam on the top or bottom side.
Please check the function after changing another MD.
5-5-3. Service hint (Any picture/ Remark)
IC400
F+: pin14
F-: pin13
IC401
< Waveform of F±
for driving focusing actuator >
< MAIN board bottom view >
3-13
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
6. NO SOUND
There is no sound output by DIGITAL AUDIO AMP DAMAGE, repair the set according to the
following guide.
6-1. DIGITAL AUDIO AMP DAMAGE
6-1-1. Solution
Replace IC701, IC702 on MAIN board.
6-1-2. How to troubleshoot (Countermeasure)
1) Check PWM_FL±, PWM_FR± & PWM_SW± signals from IC601 to IC701 & 702 each input function.
 If no signal, check if I2S audio signals are entered to IC601.
2) Check PVDD.
 If PVDD is abnormal, check the SMPS.
3) Check AMP_12V for driving the gate of AMP IC.
a. All the powers are normal, but if AMP_12V is low, there is possible for AMP IC to be damaged.
b. Remove L705, L706, L707 and L708 one by one.
When removed a inductance, if AMP_12V is recovered, the IC connected to it was damaged.
c. Replace the IC with a new one.
4) Check the impedance between IC701/IC702_OUT_A/OUT_B & GND.
a. If the impedance is 0 Ω, the IC must be damaged.
b. After removing the heat sink, replace it with a new one.
6-1-3. Service hint (Any picture/ Remark)
L706
IC702
L705
L708
IC601
IC701
L707
< MAIN board top view >
3-14
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the CD FUNCTION, repair the set according to the following guide.
6-2. CD FUNCTION
6-2-1. Solution
Replace IC501 on MAIN board.
6-2-2. How to troubleshoot (Countermeasure)
1) Check CD_BCK, CD_LRCK, & CD_DATA signals from IC501 to IC401.
 If no signal, check if the RF & servo signals from MD is entered to IC401.
Refer to the “No operation of MD” guide on Item 5.
2) Check the following I2S signal flow. < I2S audio signal Interface >
- MCS_BCK :
IC501_pin E1 --> IC601_pin23
- MCS_LRCK :
IC501_pin D1 --> IC601_pin22 (44.1 kHz)
- MIX_DATA0_OUT :
IC501_pin E2 --> IC601_pin24
- MIX_DATA2_OUT :
IC501_pin R2 --> IC601_pin26
 If there is any trouble, check the power for each IC.
The power is normal but, if the signal waveform to the IC is distorted or no signal,
replace it with a new one.
6-2-3. Service hint (Any picture/ Remark)
IC501
< MAIN board top view >
< Waveform of I2S audio interface signals >
+3.3VA
VFD_CLK
VFD_PWR_CTRL
VFD_STB
MCS_MCLK
MCS_LRCK
MCS_BCK
MIX_DATA0_OUT
DIR_SCL
DSPI_MCLK
DSPI_LRCK
DSPI_BCK
DSPI_ADATA
BT_ADC_SCL
MIC_DATA_IN
DEBUG_CON_OUT
R5B7
R5B8
R5B9
R5B37
R5B10
R5B11
R5B22
R5B23
R5B42
R5B43
R5B44
R5B12
R5B19
R5B13
100
100
100
NC
100
100
33
33
33
33
33
33
100
33
DFT_TX
D4
E5
B1
C1
C2
D2
D1
E1
E2
E4
F2
F1
G1
G2
F4
H2
G5
H1
G4
J1
H4
J2
J4
J5
VDD33IO
VSS33IO
PGPA09
PGPA10
PGPA11
PGPA12
PGPA13
PGPA14
PGPA15
PGPB00
PGPB01
PGPB02
PGPB03
PGPB04
PGPD04
PGPB05
PGPD13
PGPB06(Boot[0])
PGPD14
PGPB07(Boot[1])
PGPD15
PGPB08
VDD12INT
VSS12INT
IC501
< MAIN - CD DSP circuit >
3-15
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the USB Function, repair the set according to the following guide.
6-3. USB FUNCTION
6-3-1. Solution
Replace IC204 on MAIN board.
6-3-2. How to troubleshoot (Countermeasure)
1) Check +5V_USB to USB board.
 If the USB LED are turned on, the voltage is okay, if so not, check USB_5V to pin4, 5 of CN803.
2) Check USB D1± or USB D2± from MAIN board to TOP board.
a. Check 2.0_D1±signals(pin U7, U8 ) or 1.1_D1± signals(pin A7, A8 ) to IC501.
b. Check USB± signals to CN502(pin1, 2, 7, 8).
 If there is any trouble, check the power for IC207.
The power is normal but, if the signal waveform to the IC is distorted or no signal,
replace it with a new one.
3) Check if “Digital audio AMP block” on item 6-1 is normal.
6-3-3. Service hint (Any picture/ Remark)
D+
IC501
D-
CN502
USB D-/D+ (CN502 pin1, 2 & pin7, 8)
< Waveform of USB D± signal >
< MAIN board top view >
3-16
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the AUX Function, repair the set according to the following guide.
6-4. AUX FUNCTION
6-4-1. Solution
Replace IC301 on MAIN board.
6-4-2. How to troubleshoot (Countermeasure)
1) Check AUX_L/R signals to IC301 (pin1, 2).
2) Check if DSPI_BCK, LRCK, MCLK are entered from IC501 to IC301.
3) Check if ADC_DATA is entered from IC301 to IC501.
 If no signal, check AVCC_3.3V & DVCC_3.3V (ADC) for IC301. If is NG, replace it a new one.
4) Check the following I2S signal flow from IC501 to IC601. (Refer to Item 6-2.)
 If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform
to the IC is distorted or no signal, replace it with a new one.
5) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on Item 6-1.
 If AMP is damaged, replace it with a new one.
6-4-3. Service hint (Any picture/ Remark)
IC301
Pin15:DSPI_MCLK
Pin16:DSPI_LRCK
Pin17:DSPI_BCK
< AUX function signal flow >
< MAIN board bottom view >
3-17
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the TUNER function, repair the set according to the following guide.
6-5. TUNER FUNCTION
6-5-1. Solution
Replace IC301 on MAIN board.
6-5-2. How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from pin13, 14 of IC302 to IC301(pin27, 28)
 If no signals, check AVCC_3.3V for tuner power.
 Check if the tuner control signals (CLK, DAT, CE, RST, SLT) are entered from IC501 to IC302.
If it doesn’t work, replace IC302 with a new one.
2) Check if MCS_BCK, MCS_LRCK, & MCS_MCLK are entered from IC501 to IC201.
3) Check if ADC_DATA is entered from IC301 to IC501.
 If no signal, check AVCC_3.3V & DVCC_3.3V (ADC) for IC301. If is NG, replace it with a new one.
4) Check the following I2S audio signal flow from IC501 to IC601. (Refer to Item 6-2.)
 If there is any trouble, check the power for each IC.
The power is normal but, if the signal waveform to the IC is distorted or no signal,
replace it with a new one.
5) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on Item 6-1.
 If AMP is damaged, replace it with a new one.
6-5-3. Service hint (Any picture/ Remark)
Pin15:DSPI_MCLK
Pin16:DSPI_LRCK
Pin17:DSPI_BCK
IC301
Pin1:A_IN_L
Pin2:A_IN_R
< TUNER function signal flow >
< MAIN board bottom view >
3-18
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the PORTABLE Function, repair the set according to the following guide.
6-6. PORTABLE FUNCTION,
6-6-1. Solution
Replace IC301 on MAIN board.
6-6-2. How to troubleshoot (Countermeasure)
1) Check if PT_LR signals to IC301 (pin29, 30).
2) Check if DSPI_BCK, LRCK, MCLK are entered from IC501 to IC301.
3) Check if ADC_DATA is entered from IC201 to IC501.
 If no signal, check AVCC_3.3V & DVCC_3.3V (ADC) for IC301. If is NG, replace it with a new one.
4) Check the following I2S audio signal flow from IC501 to IC601. (Refer to Item 6-2.)
 If there is any trouble, check the power for each IC.
The power is normal but, if the signal waveform to the IC is distorted or no signal,
replace it with a new one.
5) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on Item 6-1.
 If AMP is damaged, replace it with a new one.
6-6-3. Service hint (Any picture/ Remark)
Pin15:DSPI_MCLK
Pin16:DSPI_LRCK
Pin17:DSPI_BCK
IC301
Pin29:PT_L
Pin30:PT_R
< PORT. IN function signal flow >
< MAIN board bottom view >
3-19
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the MIC IN function, repair the set according to the following guide.
6-7. MIC IN function
6-7-1. Solution
Replace IC206 on MAIN board, ICA301 on MIC & RMC board.
6-7-2. How to troubleshoot (Countermeasure)
1) Check MIC_SI & MIC_S2 signal to pin6, 8 of CN301.
 If no signal, Check the signals to pin6 & 8 of CNA301 on the MIC & RMC board.
Check if the signal is entered from pin6 & 8 of CNA301 to pin6, 8 of CN301.
2) Check if MIC_SIG is entered from pin2 of JK302 & JKA303 to pin2, 13 to ICA301 (PRE AMP).
3) Check if the amplified signal comes out from pin3 &12 of ICA301.
 If no signal output, check DVCC_3.3V for ICA301, replace ICA301 with a new one if it has a problem.
4) Check if DSPI_BCK, LRCK,MCLK are entered from IC501 to IC301.
Check if MIC_DATA_IN is entered from pin19 of IC301 to pin H2 of IC501.
 If no signal, check AVCC_3.3V & DVCC_3.3V for IC301.
If it is abnormal, change replace it a new one.
5) Check the following I2S signal flow from IC301 to IC501.
 If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
6) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on item 6-1.
 If AMP is damaged, replace it with a new one.
6-7-3. Service hint (Any picture/ Remark)
IC301
ICA301
Pin15:DSPI_MCLK
Pin16:DSPI_LRCK
Pin17:DSPI_BCK
< MIC & RMC board top view >
< MAIN board bottom view >
3-20
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the Bluetooth function, repair the set according to the following guide.
6-8. BLUETOOTH FUNCTION
6-8-1. Solution
Replace IC501 on the MAIN board or bluetooth module on the FRONT Panel.
6-8-2. How to troubleshoot (Countermeasure)
1) Check BT_RX, BT_TX signal to pin6, 4 of CN504.
 If no signal, check the signal to pin4, 6 and pin10 (3.3 VA) of on the Bluetooth module
and cable connection state.
 If there are no signal out from module, replace new module.
2) Check if BT_RX/TX is entered from pin6, 4 of CN504 to pin L1,K1 to IC501 (DSP).
3) Check if MCS_BCK, MCS_LRCK & MIX_DATA IN is entered from IC501 to IC601.
 If no signal, check +3.3 VA & +1.2 VA for IC501.
If it is abnormal, change replace it a new one.
4) Check the following I2S signal flow from IC501 to IC601.
 If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
5) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on item 6-1.
 If AMP is damaged, replace it with a new one.
6-8-3. Service hint (Any picture/ Remark)
B/T Module
CN504
BT_RX,
BT_TX
IC501
IC601
PWM
MCS_BCK
MCS_LRCK
MIX_DATA0_OUT
AMP
< Bluetooth function signal flow >
< MAIN board top view >
3-21
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the OPTICAL function, repair the set according to the following guide.
6-9. OPTICAL FUNCTION
6-9-1. Solution
Replace IC304 on the MAIN board.
6-9-2. How to troubleshoot (Countermeasure)
1) Check DSPI_BCK, LRCK, MCLK, ADATA of IC304(pin27, 28, 29, 31).
 If no signal, check the signal from JK302 pin1 to IC304 pin1
and cable connection state.
 If there are no signal out from JK302, replace new connector and cable.
2) Check if MCS_BCK, MCS_LRCK & MIX_DATA IN is entered from IC501 to IC601.
 If no signal, check +3.3 VA & +1.2 VA for IC501.
If it is abnormal, change replace it a new one.
3) Check the following I2S signal flow from IC501 to IC601.
 If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
4) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on item 6-1.
 If AMP is damaged, replace it with a new one.
6-9-3. Service hint (Any picture/ Remark)
JK302
IC304
BT_RX,
BT_TX
IC501
IC601
PWM
MCS_BCK
MCS_LRCK
MIX_DATA0_OUT
IC304
AMP
< OPTICAL function signal flow >
< MAIN board top view >
3-22
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
1. POWER (SMPS)
No 12 VA
YES
F901 normal?
NO
Replace F901 (Use the same fuse).
YES
BD901 normal?
NO
Replace BD901.
YES
TH901(TH903) normal?
NO
Replace TH901.
YES
Is Vcc
(10 V ~ 18 V) supplied to
IC901 pin2?
NO
D902 normal?
NO
Check or replace D902.
YES
D921/ D922 normal?
NO
Replace D921/ D922.
YES
Is there
about 2.5 V at
IC941 pin1?
NO
Replace IC941.
YES
D951 normal?
NO
Replace D951.
YES
ZD932 normal?
NO
Replace ZD932.
YES
Power line of main PCB is short.
3-23
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
No PVDD
YES
F901 normal?
NO
Replace F901 (Use the same fuse).
YES
BD901 normal?
NO
Replace BD901.
YES
TH901(TH903) normal?
NO
Replace TH901.
YES
Is Vcc
(10 V ~ 18 V) supplied to
IC901 pin2?
NO
D903 normal?
NO
YES
Check or replace D903.
YES
NO
Q911 base HIGH?
YES
• Check P_CTRL HIGH signal from MCS.
• Check PC902.
Check or replace Q911.
Q901 normal?
NO
Replace Q901.
YES
D951 normal?
NO
Replace D951.
YES
Is there about 2.5 V
at IC951 pin1?
NO
Replace IC951.
YES
Power line of main PCB is short.
3-24
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
No LED
YES
Is Vcc (DVCC_5V)
supplied to IC206, IC209?
NO
Check or replace IC203 block.
YES
Is SPLED & XFLED_5V is normal?
NO
Check or replace IC206, IC209.
YES
Check or replace LED harness cable.
No VFD
YES
VFD_12V is normal?
NO
Check or replace Q202, Q205.
YES
VFD_3.3V is normal?
NO
Check or replace Q203, Q206.
YES
VFD_CLK, STB, DO is normal?
NO
Check or replace R808, R811, R814.
YES
Check or replace VFD.
3-25
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
2. MCS PART CHECK
MCS PART CHECK
YES
Check if voltage
of CN201 pin1, 2: 12 V.
NO
Refer to SMPS troubleshooting.
YES
Check if IC202, IC205
have 3.3 VA & 1.2 VA output.
NO
Check and change IC202, IC205.
YES
Check if IC204
have DVCC_3.3V output.
NO
Check and change IC204.
YES
X501: 32.768 kHz, X500: 24 MHz
Check the operation.
YES
OK
3-26
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
3. FLD DISPLAY CHECK
FLD DISPLAY CHECK
YES
Check
CN201 pin1, 2: 12 V input
voltage.
NO
Refer to SMPS/MPEG
troubleshooting.
NO
Check DVCC_5V
VH : Q801, Q802, D801~D804.
YES
Check
if both end voltage
of FL+, FL- are over 1.85 V
VH : over 29 V.
YES
Check CN804
connection and DVCC_3.3V of
VDD(C806+).
NO
Check CN804 connection.
NO
Check each pin voltage.
YES
Check
IC501 -> VFD801
data communication
STB/ DATA/ CLK.
NO
Check data
IC501 pin C2, B3, B1.
YES
FLD light on?
YES
OK
3-27
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
4. PWM MODULATION CHECK
PWM MODULATION PART
CHECK
YES
Check CN201
pin1, 2: 12 V.
NO
Refer to
SMPS troubleshooting.
YES
• Check IC601(TAS5548) 3.3 V - pin9, 14, 35, 50.
• Check X601 (12.288 MHz).
YES
Check
X601(12.288 MHz)
operation.
NO
Check X601
(12.288 MHz).
NO
Replace X601(12.288 MHz).
YES
YES
OK
Check IC601 pin21 CLK input.
YES
Check IC501 (MLC3730)
pin U13: RESET, pin L14: SDA
pin L13: SCL output.
NO
Check line resistor output
RST: R508, SCL: R510,
SDA: R509.
NO
Replace R508, R510, R509.
YES
YES
OK
Check
IC601(TAS5548) input data
pin24 PWM wave.
NO
Check
CD Assy communication
Pin22, 23, 24.
YES
NO
Refer to
CD troubleshooting.
YES
Check IC601
input data.
NO
Check each line resistor output.
YES
OK
Check
PWM modulator output
FL: Pin48(-),49(+). FR: Pin46(-),47(+).
Other output
check.
NO
Check IC601.
YES
OK
NO
Replace IC601.
YES
OK
3-28
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
5. POWER AMP PART CHECK
POWER AMP PART CHECK
YES
Check CN201 pin1, 2: 12 V,
pin8, 9, 10: 48.5 V (35.5 V).
NO
Refer to SMPS troubleshooting.
YES
Check IC701, IC702
Pin51, 52, 42, 43, 38, 39, 30, 31 input voltage.
YES
Check IC701, IC702
pin64: AMP_12V input.
NO
Check each line resistor output voltage.
YES
Check PWM modulator input
IC701 pin4, 5/ IC702 pin4, 5, 10, 11.
YES
Check IC701, IC702
pin28, 29, 36, 37, 44, 45, 52, 53.
YES
Check output line coil.
NO
Replace the coil.
YES
OK
3-29
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
6. TUNER / AUX FUNCTION CHECK
FUNCTION CHECK
YES
Check
IC301 pin27, 28, 1, 2
input.
NO
Check IC302, JK301.
YES
Check
IC301 pin18
output data.
NO
Check IC301
Pin8: ADC_3.3V
Pin13, 14: DVCC_3.3V.
NO
Check CN201 pin1, 2: 12 V.
YES
IC501 output data.
NO
Replace IC501.
YES
OK
3-30
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
7. TUNER FUNCTION CHECK
TUNER FUNCTION CHECK
YES
Check tuner IC302 operation.
NO
Check tuner IC(IC302)
voltage (Pin11:AVCC_3.3V).
YES
Check IC301 Pin27, 28.
NO
Check tuner data line R & C.
YES
Refer to function check.
3-31
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
8. CD FUNCTION CHECK
CD FUNCTION
YES
Can the
disc insert?
NO
Is load +,- ok?
NO
YES
YES
YES
Is motor_open/close ok?
(IC400 pin6, 7)
Check IC400.
Is motor ok? (about 12 Ω)
NO
Check loading motor.
Check IC400 (Motor drive IC).
NO
Disc reading
is ok?
NO
IM driving
(Focus and tracking) is ok?
NO
YES
YES
Is the MD (PN401 pin22)
about 190 mV?
Is no signal at speaker?
YES
Check
the signal of IC401.
Focus,
tracking, sled signal
is ok?
NO
NO
Check MD (pick-up).
Check Vcc of IC401.
YES
Check
the signal (16.9344 MHz)
at IC401 pin49.
NO
Check cristal (X400).
NO
Replace cristal (X400).
YES
Check IC501
input/output and
control line.
NO
Replace IC501.
YES
Refer to function check.
3-32
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ELECTRICAL TROUBLESHOOTING GUIDE
9. DOUBLE USB FUNCTION
USB FUNCTION
YES
Plug-in USB device.
YES
Display “NO USB”.
YES
Display “READ”.
YES
Display “NO FILE”.
NO
Check USB_5V.
NO
Check CN502.
YES
Check USB_D+, D(R5B69,R5B70,C5B11,C5B14,
ZD505,ZD506).
NO
Check USB jack
(CN801, CN802).
YES
Check IC501
(pin U7, U8/ A7, A8).
NO
Replace IC501.
YES
Check USB audio file in USB device
(MP3, WMA file is playable)
3-33
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
CLOSE TO THE IC PIN
2.0_D1+
DGND
REMOCON
CHIP_RESET
90ohm,150mA, DCR1.4ohm
FL500
ZD506
DF3D6.8MS
2.0_D1-
ZD501
DF3D6.8MS
MCS_RTC_3.0A
C5B18
R5B83
1K
DGND
NC
C5B21
220uF
C5B19
100nF
PGPC07
PGPE00
PGPC08
PGPE01
PGPC09
PGPE02
PGPC10
PGPE03
PGPC11
PGPE04
VDD12CORE
VSS12CORE
VDD33USB20
PUID20
PUVBUS20
VDD33USB20
VSS33USB20
PUDP20
PRTUNE20
PUDN20
VSS33USB20
VDD12USB20
VSS12USB20
VDD33OSC
PXI
PXO
VSS33OSC
PDD12ALIVE
PTEST
PRESETN
PREMOCON(PGPE[10])
PHUARTRX(PGPE[11])
PGPE05
PSPDIFRX(PGPE[12])
PGPE06
PEXTSRC0(PGPE[13])
PGPE07
PEXTSRC1(PGPE[14])
PWAKEUP
1
XO
2
Fig 1-1. X501: Crystal of RTC 32.768 MHz
(R5B94 both side)
2
R5B95
330K
R5B94
10M
X501
32.768KHZ
1
3-34
C5B23
18pF
C5B24
18pF
DGND
R5B4
1.5K
3
2
3
FLOATINPUT/OUTPUT 1
X500 24MHz
INPUT/OUTPUTFLOAT 4
C5B5 12pF
C5B22
1uF
C5B20
100nF
33
100
33
100
100
100
470
100
1K
100
XI
C5B2 12pF
R5B48
R5B50
R5B52
R502
R5B55
R503
R5B58
R5B59
R5B62
R5B63
T1
P5
U1
P6
U2
P7
U3
N7
T3
P8
U4
1.2VAA
T4
C5B12
DGND 100nF
U5
T5
R5 B6 7
USB_5V R5B68
2.2K
4. 7K
T6
C5B13 C5B16 100nF
U6
100nF
T7
3.3VA
L5B4
U7
R5B71
T8
44.2
U8
DGND
T9
P9
1.2VA
N9
DGND
L5B5 C5B17 U9
+3.3VA
100nF U10
PXI
U11
PXO
U12
DGND
1.2VAA
T10
T11
T12
T13
R508
U13
100
PWM_RST
R5B87
P10
100
TUNER_CLK
U14
R5B90
P11
330
TUNER_DAT
T14
R506
N11
100
PWM_MUTE
R505
T15
100
BEAT_DET
U15
T16
U16
U17
P12
P13
DIR_RST
MOT_OPEN
ADC_DATA_IN
CD_MCK
CD_RW
TUNER_CE
CD_DIN_OUT
MOT_MUTE
CD_BUSY
TUNER_RST
WAVEFORMS OF MAJOR CHECK POINT
1. DSP (IC501)
XI
3
XO
4
Fig 1-2. X500: Crystal of system 24 MHz
( MAIN DSP : R5B6, C5B5 )
IC501
L5B6
L5B7
DGND
1.2VA
R5B6
1M
PXO
4
PXI
DGND
DGND
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2. SDRAM (IC502)
5
6
7
8
Fig 2. SDRAM
3.3VAA
IC502
VSS
DQ0
DQ15
2
M00
3
VDDQ
VSSQ
DQ1
DQ14
DQ2
DQ13
VSSQ
VDDQ
DQ3
DQ12
DQ4
DQ11
VDDQ
VSSQ
4
M01
5
M02
6
7
M03
8
M04
9
10
M05
11
M06
12
13
M07
14
15
A15
DRM_WEN
R5B115
22
16
17
DRM_CAS
18
DRM_RAS
19
DRM_SEL
20
A13
21
A14
22
A10
23
A00
24
A01
25
A02
26
A03
27
6
VDD
DQ5
DQ6
VSSQ
DQ10
DQ9
VDDQ
DQ7
DQ8
VDD
VSS
LDQM
NC
WE
UDQM
CAS
CLK
RAS
CKE
CS
A12
BS0
A11
BS1
A9
A10/AP
A8
A0
A7
A1
A6
A2
A5
A3
A4
VDD
DGND
VSS
54
53
M15
52
51
M14
50
M13
49
48
M12
47
M11
46
45
M10
44
M09
43
42
M08
41
40
39
5
A16
38
DRM_CLK
37
DRM_CKE
36
A12
35
A11
34
A09
33
32
7
A08
A07
31
A06
30
A05
29
A04
28
10pF
NC
1
C5B60
8
(SDRAM)
DGND
3-35
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3. SERVO (IC401)
XI
9
11
XO
10
Fig 3-2. CD-16M
(IC401 pin31)
Fig 3-1. X400: Crystal 16.9344 MHz
DGND
XBUFO
RESETB
CLK
CLK88
VDD_CORE
DGND
WFCK
SUBDATA
SUBCK
BUSY
SUBSYQ
R/W
DVDD
RXO
MCK
RXI
DIN/DOUT
IC401
3-36
32
30
31
29
28
27
26
24
25
23
22
20
21
RFGND
RFGND
VDD_CORE
R419
33
CD_16M
11
CD_RESB
CD_SUBSYQ
CD_RW
RFGND
CD_BUSY
C444
15pF
15pF
RFGND
CD_DIN_OUT
10
C445
C431
100nF
DVCC3.3V
C424
100nF
CD_MCK
9
19
17
R422
X400
220
16.9344MHz
RFGND
1M
18
R423
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
4. MOTOR DRIVER (IC400)
16
12
17
13
14
15
Fig 4-2. SL- & SL+ for Driving SPINDLE Motor
(IC400 Pin11, 12)
Fig 4-1. LO- & LO+ / MOT_OPEN &MOT_CLOSE
for Driving TRAY Motor
(IC400 Pin6, 7, 9, 10)
18
19
Fig 4-3. SP- & SP+ for Driving SPINDLE Motor
(IC400 Pin17, 18)
2
VINFC
TRB_1
3
4
SLD0
MOT_CLOSE
15
13
VINTK
VINSL+
TRB_2
REGO 1
RESET
FWD
VINLD
6
7
REV
M_5V
LOAD+
C428
100nF
C440
100nF
16V
220uF
C427
GND
28
MOT_MUTE
27
12
TRD
25
24
23
VOTR-
VCCD
VOTR+
Vcc2
VOSL+
VOLD-
VOSL-
VOLD+
VOFC-
VOTK-
VOFC+
VOTK+
11
SLED+
12
SLED-
F+
Vcc1
10
17
16
C415
47nF
13
14
3-37
SPD0
22
MGND
VCTL
9
LOAD-
F-
8
VREF
26
IC400
14
MGND
BIAS
REGO 2
5
MOT_OPEN
MUTE
R417
5.6K
21
20
19
R416
15K
1
FD0
MGND
M_5V
18
SPIN-
17
19
16
15
18
SPIN+
TR+
TR-
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
5. ADC (IC301)
6. USB (CN502)
20
21
23
22
24
Fig 5. ADC I2S
(IC301 Pin15, 16, 17)
ADC
AGND
C317
1nF
C321
10uF
R322
5.6K
C318
1nF
C322
10uF
R323
5.6K
5
6
7
8
9
VREF
AVDD
12
13
14
15
MS/AD
MC/SCL
D
MOSI/SDA
MISO/GPIO0
XO
10
11
A
AGND
27
26
25
GPIO3/IntC
DOUT
IOVDD
BCK
SCKI(3.3V)
LRCK
C320
10uF
R311
2.7K
R305
10K
R334
100K
AGND
CN502
TUNER_L
100
TP301
100
TP302
R308
TP304
33
18
R312
33
17
R313
33
16
R318
33
TP312
R309
33
TP313
21
TP310
1
D2-
2
USB_5V
USB_5V
ADC_DIR_DAT
22
DGND
2.0_D1+
TP511
TP507 R504 4.7
4
5
6
7
D1-
8
C534 C537 C536
NC
NC 100nF
TP513
TP512
DGND
TP516
TP515
USB_5V
2.0_D1-
3
24
D1+
24
MIC_DATA_IN
R501 4.7
D2+
DGND
BT_ADC_SCL
22
19
Volume(USB)<-> Main
23
R335
100K
AGND
DVCC_3.3V
R307
20
DVDD
C316
AGND 1nF
R306
GPIO2/IntB/DMCLK
DGND
R310
2.7K
24
21
LDO
C319
10uF
23
GPIO1/IntA/DMIN
XI
TUNER_R
C315
1nF
28
L513
4
30
29
1.1_D+
1.1_D-
UBW2012-121F
3
VINR3/VIN3P
VINL2/VIN1M
VINL3/VIN4P
VINR2/VIN2M
VINR4/VIN3M
VINL1/VIN1P
VINL4/VIN4M
VINR1/VIN2P
MD0
MicBias
R333
100K
AGND
ZD507
2
PT_R
R332
100K
AGND
PT_L
IC301
1
Fig 6. USB D+/D(CN502 Pin1, 2, 7, 8)
DGND
23
ADC_DATA_IN
TP311
DSPI_BCK
DSPI_LRCK
DSPI_MCLK
DGND
20
3-38
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
7. BLUETOOTH (CN504)
BT_RX
BT_RX
BT_RST
27
BT_RST
Fig 7. BT_TX / BT_RX / BT_RST
3.3VA
R5B1
R5B2
BT Module<-> Main
CN504
SDA
2
GND
3
TXD
4
GND
5
RXD
6
4.7K
4.7K
L505
1
SCL
TP501
TP502
C514
TP503
33pF
L506
C522
33pF
NC L507
25
7
CTS
8
RESET
9
BT_ADC_SCL
L508
BTGND DGND
BT_RX
TP505
BT_RTS
TP506
TP508
26
TP509
VDD
BT_DAT
BT_TX
TP504
RTS
10
BT_CTS
27
BT_RST
C512
100nF
C513
100pF
C515
100pF
C524
100pF
C532
100pF
L502
C510 10uF
3.3VA
C509100nF
TP510
C508 10uF
26
B
T_TXBT_TX
BT_TX
C561 10uF
25
DGND
3-39
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3-40
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
WIRING DIAGRAM
Harness
FAN
FFC
3pin
3pin
4pin
CN502
USB
3pin
8pin
8pin
Speaker
Unit
RF par t
I C400
10pin
10pin
RF par t
Mot or
I C401
BT
WAFER
CN504
10pin
Mi com #1
I C101
Wir el ess
WAFER
CN103
26pin
LED CTRL
Mi com #2
I C111
25pi n
WAFER
CN102
MI C
WAFER
CN301
25pin
8pin
WAFER
CN201
14pin
Sparkle
LED
XFlash
LED
Sparkle
LED
4pin
12pin
SPK
LED
10pin
BT
26pin
WIRELESS
[option]
25pin
8pin
ICA301
MIC AMP
DRV632
MIC1
3-41
RMC
3-42
DN LED
12pin
Front Board
TOP Control Board
UP LED
6pin
15pin
MD
15pin
MAIN Board
I C501
MLC3730
14pin
6pin
Li ght i ng
CN107
23pin
23pin
XFlash
LED
SDRAM
I C502
Li ght i ng
CN106
USB2
AUX
PART
I C301
4pin
USB
PWM
TAS5548
I C601
Heat si nk
DI R
CS8422
I C304
FAN
AUX
JACK
JK301
Por t abl e
JK303
Speaker
3pi n
FM
WAFER
CN302
Speaker
4pi n
USB1
Opt i cal
JACK
JK302
SMPS
MIC2
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
BLOCK DIAGRAM
CD_RESB_16M_SUBSYQ
_DIN OUT_BUSY
SERVO
( x4 )
ANALOG INPUT Block
CD_RW/MCK/LRCK/BCK
,
CD_DATA
DECK
MECHANISM
MOT_MUTE/CLOSE/OPEN
Motor Drive
OP_SW,CL_SW
24M
Hz
32MB
SDRAM
16MB
Flash
TOP
BLOCK
(+3.3VA,5V,+12V)
2.0
1.1
USB1 USB2
VFD
PTB
PTB_L/R
PORTABLE IN
AUX
AUX_L/R
AUX IN
32.768MHz
ADC
TUNER_L/R
Si4705
FM
(+3.3V_CD, VCC1.2)
MD Block
OK75 : USB1/2
OK55 : USB1
DIR_INT/RST/
CSD/TEMP
LOAD± ,SLED± ,
SPIN± ,TR± ,F±
8MB
S/Flash
MIC_DATA_IN, ADC_DATA_IN
BT_ADC_DIR_SCL / ADC_DIR_DAT
SF_MOSI/MISO
SF_CS/SCK
For MIC
Main DSP
IR
Receiver
SF_MOSI/MISO
SF2_CS/SCK
FRONT Block
D1+/ -, D2S+/ VFD_STB/CLK/DO
MAIN V_A/B,
KEY 1/2/3, LANDING_GEAR
PWM + AMP Block
PWM_SCL/DAT
PWM_RST/MUTE
MIX_DATAx_OUT
Sparkle
Lighting
X-Flash
Lighting
Wireless
Option
WL_SPI_DI
1MB
S/Flash
WL_SPI_CLK/
CS/DO/WP
Front-R
295W
(160W)
To Wireless
Block
3-43
SW(PBTL)
410W
(180W)
FAN
WL_SCL/SDA/INT/MSG_RDY
TOP Block
295W
(160W)
PWM
AMP
Multi Speaker
Lighting
Front-L
AMP
Micom
#1/#2
( 48Pin )
Thruster
LPF
MIX_DATA0~2
MCS_CS/RX/TX
Party
OK75
(OK55)
MCS_LRCK/BCK
OK75 : O
OK55 : X
Key/switch
MIC 1
MIC 2
DRV603
DSPI_MCLK/LRCK/BCK
For RCU
Volume/
TUNER
(FM/)
ADC_DATA (for AUX)
DRM_WEN/CAS/
RAS/SEL/CLK/CKE
M00_15,A00_16
BT_TX_RX
M
BT_ADC_DIR_SCL
/ ADC_DIR_DAT
DIR
SPDO/SLDO
/ FDO/TRD
BT_PCM_BUFFER
P/UP
24.576MHz
DSPI_MCLK/LRCK/
BCK/ADATA
(VCC50)
AC,BD,E,F,PD,CD_LD
OK75 : O
OK55 : X
OPTICAL
IN
24MHz
[OK75 : Total 1 000W]
FRONT :
295W X
2CH
WOOFER : 410W X 1CH
DSP_I2S_LRCK/BCK,
DSP_C_WF
3-44
[OK55 : Total 500W]
FRONT : 160W X 2CH
WOOFER : 180W X 1CH
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
CIRCUIT VOLTAGE CHART
1. IC VOLTAGE
NO.
SYMBOL
SPEC
(V, mV)
2. FAN MOTOR VOLTAGE
Rating -20 %
Rating +20 %
Measured Voltage
IC function
Voltage (V)
Voltage (V)
Description of operation
IC TC TEMPERATURE
SPEC
1
IC101
IC,Microcontrollers
VDD : -0.5~+6.5V
VDD : 3.1 ~ 3.3V
VDD : 3.29V
IC,Microcontrollers
125 °C
2
IC111
IC,Microcontrollers
VDD : -0.5~+6.5V
VDD : 3.1 ~ 3.3V
VDD : 3.28V
Sub IC,Microcontrollers
125 °C
3
IC201
DC,DC Converter
VIN : 4.5V TO 24V
Vin : 12VA,
Vout : 5.1VA
Vin : 12.01VA,
Vout : 5.15VA
High Efficiency 3A, 24V, 500kHz
Synchronous Step Down Converter
125 °C
4
IC202
DC-DC Converter
VIN : 2.7V TO 5.6V
Vin : 3.3VA,
Vout : 3.3V
Vin : 5.15VA
Vout : 3.34VA
Step-Down Converters
125 °C
5
IC203
DC,DC Converter
VIN : 4.5V TO 24V
Vin : 12VA,
Vout : 5.1VA
Vin : 12.01VA,
Vout : 5.11V
High Efficiency 3A, 24V, 500kHz
Synchronous Step Down Converter
125 °C
6
IC204
Limit Switch
VIN : 2.5V TO 5.5V
Vin : 5.1VA,
Vout : 5V
Vin : 3.34VA
Vout : 3.29V
ultra-low RDS(ON) switch
with current limiting
125 °C
7
IC205
DC-DC Converter
VIN : 2.7V TO 5.6V
Vin : 5.1VA,
Vout : 1.2VA
Vin : 5.14VA,
Vout : 1.22V
Step-Down Converters
125 °C
8
IC206
Limit Switch
VIN : 2.5V TO 5.5V
Vin : 5.1VA,
Vout : 5.0V
Vin : 5.1VA
Vout : 5.0V
ultra-low RDS(ON) switch
with current limiting
125 °C
9
IC207
Limit Switch
VIN : 2.5V TO 5.5V
Vin : 5.1VA,
Vout : 5V
Vin : 5.15VA
Vout : 5.14V
ultra-low RDS(ON) switch
with current limiting
10
IC208
DC-DC Converter
VIN : 4.5V TO 5V
Vin : 5.1V
Vout : 3.3V
Vin : 5.14VA
Vout : 3.3V
11
IC209
Limit Switch
VIN : 2.5V TO 5.5V
Vin : 5.1A,
Vout : 5.0V
12
IC301
4ch Audio ADC
VIN : -0.3V to 3.9V
13
IC302
TUNER
14
NO.
Check MODE
SPEC
1
FAN MOTOR
Input Voltage
2
FAN MOTOR
Operation Voltage
Check Result
Check Method
12V
11.98V
Check the Voltage
on the CN462
Pin3(FAN_DC),
Not connect FAN
Module.(12V)
VOL14 : 4.6~5.6V
VOL15~40 :
7.8~9.6V
VOL14 : 5.1V
VOL15~40 : 8.7V
During the FAN
Operate, Check
the Voltage of FAN
Module.
3. SMPS CAPACITOR & ZENER DIODE
Capacitor
NO
LOC
SPEC
Sales AREA
125 °C
1
C903
450V/
330uF
W/W
Step-Down Converters
125 °C
2
C904
450V/
330uF
W/W
Vin : 5.1VA
Vout : 5.0V
ultra-low RDS(ON) switch
with current limiting
125 °C
AVDD : 3.3V
AVDD : 3.31V
4ch Audio ADCs
with Universal Front End Input Mux
125 °C
VDD:3~3.6V
VDD:3.3V
AVDD:3.32V
Tuner ic
150 °C
IC304
OPTICAL
VDD:3~3.6V
VDD:3.3V
AVDD:3.32V
Optical
125 °C
15
IC400
Motor Driver
VCC1 : 4.3~13.2V
VCC2 : 4.3~VCC1
VCC1 : 5.0V
VCC2 : 5.0V
VCC1 : 5.11V
VCC2 : 5.11V
5-channel BTL Driver
150 °C
16
IC401
digital servo signal processing
VDD1 : 2.7~3.6V (Analog)
VDD_CORE : 1.4~1.65V
VCC : 3.3V
VCC : 3.28V
Servo signal processor
for compact disc player
125 °C
17
IC501
IC,Digital Signal Processors
Digital Power 3.3V or 1.2V
VDD33 : 3.3VA
VDD12 : 1.2VA
VDD : 3.33VA
VDD : 1.21VA
IC,Digital Signal Processors
150 °C
18
IC502
SDRAM
VDD : 3.0~3.6V
VCC : 3.3V
VCC : 3.33V
4 M x 4 BANKS x 16 BITS SDRAM
150 °C
19
IC503
Serial Flash Memory
VDD : 3.0~3.6V
VCC : 3.3V
VCC : 3.33V
SERIAL FLASH MEMORY
150 °C
20
IC504
Serial Flash Memory
VDD : 3.0~3.6V
VCC : 3.3V
VCC : 3.33V
SERIAL FLASH MEMORY
150 °C
21
IC505
RESET
VIN:1.1~5.5V
Vin : 3.1~3.3VA
Vin : 3.32VA
3-PIN MICROPROCESSOR RESET
CIRCUITS
125 °C
22
IC601
Sound/Audio Processor
VCC : 2.97V TO 3.63V
VDD : 3.3V
VDD : 3.27V
Digital Audio Processor
125 °C
23
IC700~IC702
AUDIO AMPLIFIER
VCC : 11.6V To 12.4V
VDD : 11.68V
PVDD : 48.2V
VDD : 11.68V
PVDD : 48.2V
PROTECTED DIGITAL AUDIO
AMPLIFIER
125 °C
24
ICA301
Line Driver
VDD:3~3.6V
VDD : 3.3V
VDD : 3.32V
2-VRMS Audio Line Driver
With Adjustable Gain
150 °C
3-45
3-46
SMPS ZENER DIODE
NO
LOC
CHECK
1
ZD902, ZD906
13V
2
ZD901, ZD904
33V
3
ZD905, ZD912
20V
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
4. MAIN CAPACITOR
5. CONNECTOR VOLTAGE
NO.
LOCATION NO.
Value
1
C257
470uF
2
C271
220uF
3
C345
220uF
4
C402
100uF
5
C404
6
C409
7
8
110V-20%
220V+20%
(88V/60Hz) V
(288V/50Hz) V
+12V
NO.
LOCATION
NO.
Connector Name
PIN NO.
PIN MANE
12.06
1
USB_5V
5.03
DVCC_3.3V
3.28
DVCC_5V
5.03
47uF
DVCC_3.3V
3.27
47uF
DVCC_3.3V
C416
47uF
C418
3.3uF
Voltage(V)
Vin
Vout
D2+
0.01
0.01
2
D2-
0.07
0.07
3
DGND
0.00
0.00
4
USB_5V
5.17
5.17
5
USB_5V
5.17
5.17
3.27
6
DGND
0.00
0.00
DVCC_3.3V
3.27
7
D1+
0.03
0.03
VREF
1.63
8
D1-
0.01
0.01
1
CN502
MAIN  TOP(USB)
9
C427
220uF
M_5V
5.03
1
SDA
0.12
0.12
10
C481
100uF
FAN_DC
11.98
2
SCL
3.33
3.33
11
C5B21
220uF
VDD_CORE
1.26
3
GND
0.00
0.00
12
C614
100uF
DVCC_3.3V
3.28
4
TXD
3.33
3.33
5
GND
0.00
0.00
6
RXD
3.33
3.33
RTS
1.49
1.49
13
C713
10uF
+12V
11.91
14
C714
10uF
+12V
11.91
15
C748
680uF
+B +66V
48.30
7
16
C749
680uF
-B -66V
48.30
8
CTS
1.51
1.51
17
C752
680uF
+B +66V
48.30
9
RESET
3.33
3.33
18
C753
680uF
-B -66V
48.30
10
VDD
3.33
3.33
19
C801
100uF
USB_5V
5.21
1
GND
0.00
0.00
2
CN504
MAIN  BT Moudle
20
C802
47uF
F-
3.07
2
GND
0.00
0.00
21
C805
1uF
VFD_12V
11.95
3
MAIN_VOL_A
3.33
3.33
22
C806
1uF
DVCC_3.3V
3.29
4
MAIN_VOL_B
3.32
3.32
23
C813
100uF
USB_5V
5.21
5
FILE_S_A
3.29
3.29
24
C821
47uF
F+
5.18
6
FILE_S_B
3.29
3.29
25
C831
1uF
VH
29.81
7
SCRATCH_B
3.29
3.29
26
C832
1uF
VH
20.90
8
SCRATCH_A
3.29
3.29
27
C833
1uF
VH
20.90
9
MIC_VOL_B
3.29
3.29
28
C834
1uF
VH
16.80
10
MIC_VOL_A
3.29
3.29
29
C903
330uF
122.30
372.10
11
KEY1
3.27
3.27
30
C904
330uF
122.30
372.10
12
KEY2
3.27
3.27
31
C933
2200uF
12.10
12.10
13
KEY3
3.27
3.27
32
C934
470uF
12.10
12.10
33
C952
2200uF
49.10
49.10
14
LANDING
GEAR
3.33
3.33
34
C953
2200uF
49.10
49.10
15
GND
0.00
0.00
3-47
3
CN102
3-48
MAIN  TOP
12511HS-25SS-K
16
+3.3V
3.35
3.35
17
DGND
0.00
0.00
18
VFD_DAT
3.14
3.14
19
VFD_STB
3.14
3.14
20
VFD_CLK
3.14
3.14
21
DV_3.3V
3.33
3.33
22
DV_5.0V
5.05
5.05
23
DV_5.0V
5.05
5.05
24
VF_12V
12.02
12.02
25
GND
0.00
0.00
LOCATION
NO.
CN803
BT
Module
CN804
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
CONNECTOR VOLTAGE
NO.
4
5
6
LOCATION
NO.
CN201
CN301
CN400
Connector Name
MAIN  SMPS
MAIN  MIC
SMW200-H8G
MAIN  MD
PIN NO.
PIN MANE
1
Voltage(V)
LOCATION
NO.
NO.
LOCATION
NO.
Connector Name
PIN NO.
PIN MANE
OPEN_SW
Voltage(V)
Vin
Vout
12V
12.06
12.06
1
2
12V
12.06
12.06
2
LO-
0.00
3
DGND
0.00
0.00
3
CLOSE_SW
3.33
4
P_CTRL
3.33
3.33
4
LO+
0.01
5
DGND
0.00
0.00
5
GND
0.00
6
DGND
0.00
0.00
6
SP+
2.47
7
DGND
0.00
0.00
7
SL+
2.47
8
PVDD
48.30
48.30
8
SP-
2.47
7
CN401
MAIN  MD
CN901
Vin
Vout
3.29
9
PVDD
48.30
48.30
9
SL-
2.47
10
PVDD
48.30
48.30
10
NC
0.00
11
DGND
0.00
0.00
1
SW+
24.40
12
PVDD CTRL
2.83
2.83
2
SW-
24.40
3
FL+
24.40
4
FL-
24.40
5
FR+
24.40
1
RMC3.3VA
3.33
3.33
2
RMC
3.19
3.19
3
DGND
0.00
0.00
4
MIC_3.3V
3.28
3.28
5
MIC_DET
3.29
3.29
6
MIC_S1
0.00
7
MIC_GND
0.00
0.00
8
MIC_S2
1
NC/FHM-VCC
5.05
2
RF
0.02
8
CN701
MAIN  SPK
DVD_LD
0.02
4
MON(COM)/5V
0.02
5
DVD_VR
0.03
6
GND
0.00
7
VREF/VC
1.63
8
VCC
5.05
9
F
1.63
10
E
1.63
11
A
1.63
12
D
1.63
13
C
1.63
14
B
1.63
15
F(+)
2.47
16
T(+)
2.46
17
T(-)
2.46
18
F(-)
2.47
19
SW_PDIC
4.69
20
GND
0.00
21
CD_LD
0.02
22
MON_MPD
0.21
23
CD_VR
0.00
SPK
FR-
1
GND
0.00
0.00
0.00
2
SPRK_U_LD3
0~3
0~3
0.00
3
SPRK_U_LD2
0~3
0~3
4
FLASH_
BLUE_L
0~3
0~3
5
FLASH_RED_L
0~3
0~3
6
GND
0.00
0.00
7
GND
0.00
0.00
8
SPRK_U_RD5
0~3
0~3
9
SPRK_U_RD4
0~3
0~3
10
FLASH_
BLUE_R
0~3
0~3
11
FLASH_RED_R
0~3
0~3
12
GND
0.00
0.00
1
MULTI_LED_B
0~3
0~3
2
MULTI_LED_G
0~3
0~3
3
MULTI_LED_R
0~3
0~3
4
GND
0.00
0.00
5
GND
0.00
0.00
6
SPRK_D_LD3
0~3
0~3
7
SPRK_D_LD2
0~3
0~3
8
SPRK_D_LD1
0~3
0~3
9
GND
0.00
0.00
10
GND
0.00
0.00
11
SPRK_D_LD6
0~3
0~3
12
SPRK_D_LD5
0~3
0~3
13
SPRK_D_LD4
0~3
0~3
0.00
3
MD
6
CNA301
9
CN106
MAIN  SPARKLING
LIGHTING(UP)
1.25MM
MD
10
3-49
CN107
3-50
MAIN  SPARKLING
LIGHTING(DN)
1.25MM
LOCATION
NO.
24.40
CNS101
CNS102
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
CONNECTOR VOLTAGE
NO.
LOCATION
NO.
Connector Name
PIN NO.
PIN MANE
CN107
MAIN  SPARKLING
LIGHTING(DN)
1.25MM
14
10
11
12
13
14
CN462
CNS103
CNF103
CNF104
MAIN  FAN CONTROL
SPAKLING DN  SPK LED
Voltage(V)
Vin
Vout
GND
0.00
0.00
15
GND
0.00
0.00
1
GND
0.00
0.00
2
NC
0.00
0.00
3
FAN_DC
8.70
8.70
1
SPKLED_B
0~3
0~3
2
SPKLED_G
0~3
0~3
3
SPKLED_R
0~3
0~3
4
GND
0.00
0.00
1
GND
0.00
0.00
2
GND
0.00
0.00
3
FLASH_
BLUE_L_UP
0~3
0~3
4
FLASH_
BLUE_L_UP
0~3
0~3
5
FLASH_
RED_L_UP
0~3
0~3
6
FLASH_
RED_L_UP
0~3
0~3
7
GND
0.00
0.00
8
GND
0.00
0.00
1
GND
0.00
0.00
2
GND
0.00
0.00
3
FLASH_
BLUE_R_UP
0~3
0~3
4
FLASH_
BLUE_R_UP
0~3
0~3
5
FLASH_
RED_R_UP
0~3
0~3
6
FLASH_
RED_R_UP
0~3
0~3
7
GND
0.00
0.00
8
GND
0.00
0.00
FRONT  FRONT
FRONT  FRONT
LOCATION
NO.
CNS102
FAN
CNS301
CNF101
CNF102
3-51
3-52
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
PRINTED CIRCUIT BOARD DIAGRAMS
1. SMPS P.C.BOARD DIAGRAM
(TOP VIEW)
3-53
3-54
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
SMPS P.C.BOARD DIAGRAM
(BOTTOM VIEW)
NOTE) Warning
Parts that are critical with respect to risk
of fire or electrical shock.
3-55
3-56
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
2. MAIN P.C.BOARD DIAGRAM
(TOP VIEW)
3-57
3-58
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
MAIN P.C.BOARD DIAGRAM
(BOTTOM VIEW)
3-59
3-60
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3. TOP P.C.BOARD DIAGRAM
(TOP VIEW)
3-61
3-62
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
TOP P.C.BOARD DIAGRAM
(BOTTOM VIEW)
3-63
3-64
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
4. JACK & RMC P.C.BOARD DIAGRAM
(TOP VIEW)
(BOTTOM VIEW)
3-65
3-66
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
5. SPARKLE LED UP P.C.BOARD DIAGRAM
(TOP VIEW)
(BOTTOM VIEW)
6. SPARKLE LED DOWN P.C.BOARD DIAGRAM
(TOP VIEW)
(BOTTOM VIEW)
3-67
3-68
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
7. X-FLASH LED UP LEFT P.C.BOARD DIAGRAM
8. X-FLASH LED UP RIGHT P.C.BOARD DIAGRAM
(TOP VIEW)
(TOP VIEW)
(BOTTOM VIEW)
(BOTTOM VIEW)
9. SPEAKER LED P.C.BOARD DIAGRAM
(TOP VIEW)
(BOTTOM VIEW)
3-69
3-70
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
3-71
3-72
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
SECTION 4
MECHANISM (DM19D)
CONTENTS
DECK MECHANISM DISASSEMBLY
1. Cover Top ............................................................................................................................................... 4-2
2. Clamp Assembly ..................................................................................................................................... 4-2
2-1. Plate ................................................................................................................................................. 4-2
2-2. Magnet ............................................................................................................................................. 4-2
2-3. Clamp............................................................................................................................................... 4-2
3. Tray Disc ................................................................................................................................................. 4-3
4. Pick Up Assembly ................................................................................................................................... 4-4
5. Base Up/Down ........................................................................................................................................ 4-4
6. Belt Loading ............................................................................................................................................ 4-5
7. Gear Pulley ............................................................................................................................................. 4-5
8. Gear Loading .......................................................................................................................................... 4-5
9. Guide ....................................................................................................................................................... 4-5
10. Deck PCB Assembly ............................................................................................................................... 4-5
11. Motor Assembly ...................................................................................................................................... 4-5
12. FFC Cable ............................................................................................................................................... 4-5
DECK MECHANISM EXPLODED VIEW (DM19D) ........................................................................................... 4-6
4-1
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DECK MECHANISM DISASSEMBLY
(S1)
1
1
Clamp
Assembly
Cover Top
2
2
Clamp Assembly
Plate
Magnet
Clamp
< Figure A >
< Figure B >
1. Cover Top
2. Clamp Assembly
1) Remove the 2 screws (S1).
2) Remove the Cover Top.
1) Place the Clamp Assembly as Figure B.
2) Bending the Cover Top in direction of
arrow (2) as Figure B.
3) Separate the Clamp Assembly from the
Cover Top.
2-1. Plate
1) Turn the Plate to a counterclockwise direction
and then lift up the Plate.
2) Remove the Plate.
2-2. Magnet
Remove the Magnet.
2-3. Clamp
Remove the Clamp.
4-2
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DECK MECHANISM DISASSEMBLY
Emergency eject hole
MD Sub
Assembly
(H1)
1
Tray Disc
1
2
2
1
< Bottom side view >
3
Tray Disc
< Figure D >
2
Tray Disc
3) Grasp the both sides of the Tray Disc and lift
it up as Figure D, and then pull the Tray Disc
until it is separated from the MD Sub Assembly
completely.
< Figure C >
3. Tray Disc
1) Insert and push a flat-head screwdriver in the
Emergency eject hole (H1) at the right side, so
that the Tray Disc is ejected about 15 ~ 20 mm.
2) Pull the Tray Disc until it is locked.
Guide
Tray Disc
< Figure E >
Note
• When reassembling place the Guide as Figure E.
4-3
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DECK MECHANISM DISASSEMBLY
Gasket Tape
Base Up/Down
1
RE B
OR BR D LK
N N
BK
RE
2
(D)
Deck PCB
Assembly
(B)
D
3
(L2)
1
2
(H2)
< Bottom side view >
(S2)
Base Main
3
5
Rubber
Damper
Figure G-3
(C)
(A)
FFC Cable
Guide
Pick Up
Assembly
4
(B)
Figure G-1
Figure G-2
Base
Up/Down
< Figure G >
5. Base Up/Down
Unlock the Locking Tab (L2) in direction of arrow
and then lift up the Base Up/Down to separate it
from the Base Main.
< Figure F >
Note
4. Pick Up Assembly
• When reassembling move the Guide in direction
of arrow (A) until it is positioned as Figure G-1.
• When reassembling insert the (B) portion of the
Base Up/Down in the (C) portion of the Guide as
Figure G-2.
• When reassembling insert the (D) portion of the
Base Up/Down in the Hole (H2) of the Base Main
as Figure G-3.
1) Detach the Gasket Tape.
2) Disconnect the wires (BLK, RED, BRN, ORN)
from the Deck PCB Assembly by desoldering.
3) Remove the 4 screws (S2).
4) Disconnect the FFC Cable from the Pick Up
Assembly.
5) Remove the 4 Rubber Dampers.
4-4
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DECK MECHANISM DISASSEMBLY
Base Main
(A)
Figure H-1
Guide
(B)
Gear Loading
Gear Pulley
(L3)
Base Main
< Bottom side view >
Belt Loading
(L4)
RE B
OR BR D LK
N N
BK
< Bottom side view >
Motor
Assembly
RE
D
< Bottom side view >
(S3)
Deck PCB
Assembly
Deck PCB
Assembly
< Figure H >
6. Belt Loading
10. Deck PCB Assembly
Remove the Belt Loading.
1) Disconnect the wires (RED, BK) form the
Deck PCB Assembly by desoldering.
2) Remove the 1 screw (S3).
3) Separate the Deck PCB Assembly from the
Base Main.
7. Gear Pulley
Unlock the Locking Tab (L3) in direction of arrow
and then separate the Gear Pulley from the Base
Main.
8. Gear Loading
11. Motor Assembly
Unlock the Locking Tab (L4) in direction of
arrow and then separate the Motor Assembly
from the Base Main.
Remove the Gear Loading.
9. Guide
1) Move the Guide in direction of arrow (A) as
Figure H-1.
2) Separate the Guide from the Base Main.
12. FFC Cable
Remove the FFC Cable.
4-5
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
DECK MECHANISM EXPLODED VIEW (DM19D)
A00
1030
1049
1015
A005
4-6
Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.