LG SJ2 User manual

SERVICE MANUAL
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
Internal Use Only
Wireless Sound Bar
JUNE, 2017P/NO : AFN78037532
MODEL: SJ2 (SJ2, SPJ2B-W)
MODEL: SJ2 (SJ2, SPJ2B-W)

1-1
CONTENTS
SECTION 1 ........ SUMMARY
SECTION 2 ........ CABINET & MAIN CHASSIS
SECTION 3 ........ ELECTRICAL
SECTION 4 ........ WIRELESS SUBWOOFER PART

1-2
SECTION 1
SUMMARY
CONTENTS
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO PRODUCTS.................................................... 1-3
SERVICING PRECAUTIONS ............................................................................................................................ 1-4
• GENERAL SERVICING PRECAUTIONS
• INSULATION CHECKING PRODEDURE
• ELECTROSTATICALLY SENSITIVE (ES) DEVICES
NAME OF EACH COMPONENT ....................................................................................................................... 1-5
WIRELESS SUBWOOFER CONNECTION....................................................................................................... 1-6
HIDDEN KEY MODE ......................................................................................................................................... 1-7
SOFTWARE UPDATE GUIDE........................................................................................................................... 1-8
SPECIFICATIONS ............................................................................................................................................. 1-9

1-3
PRODUCT SAFETY SERVICING GUIDELINES
FOR AUDIO PRODUCTS
IMPORTANT SAFETY NOTICE
This manual was prepared for use only by properly trained audio-video service
technicians.
When servicing this product, under no circumstances should the original design be
modified or altered without permission from LG Corporation. All components should
be replaced only with types identical to those in the original circuit and their physical
location, wiring and lead dress must conform to original layout upon completion of
repairs.
Special components are also used to prevent x-radiation, shock and fire hazard.
These components are indicated by the letter “x” included in their component des-
ignators and are required to maintain safe performance. No deviations are allowed
without prior approval by LG Corporation.
Circuit diagrams may occasionally differ from the actual circuit used. This way, imple-
mentation of the latest safety and performance improvement changes into the set is
not delayed until the new service literature is printed.
CAUTION : Do not attempt to modify this product in any way. Never perform cus-
tomized installations without manufacturer’s approval. Unauthorized modifications
will not only void the warranty, but may lead to property damage or user injury.
Service work should be performed only after you are thoroughly familiar with these
safety checks and servicing guidelines.
GRAPHIC SYMBOLS
The exclamation point within an equilateral triangle is intended to alert
the service personnel to important safety information in the service
literature.
The lightning flash with arrowhead symbol within an equilateral
triangle is intended to alert the service personnel to the presence of
noninsulated “dangerous voltage” that may be of sufficient magnitude
to constitute a risk of electric shock.
The pictorial representation of a fuse and its rating within an equilat-
eral triangle is intended to convey to the service personnel the follow-
ing fuse replacement caution notice:
CAUTION : FOR CONTINUED PROTECTION AGAINST RISK
OF FIRE, REPLACE ALL FUSES WITH THE SAME TYPE AND
RATING AS MARKED NEAR EACH FUSE.
SERVICE INFORMATION
While servicing, use an isolation transformer for protection from AC line shock. After
the original service problem has been corrected, make a check of the following:
FIRE AND SHOCK HAZARD
1. Be sure that all components are positioned to avoid a possibility of adjacent com-
ponent shorts. This is especially important on items trans-ported to and from the
repair shop.
2. Verify that all protective devices such as insulators, barriers, covers, shields, strain
reliefs, power supply cords, and other hardware have been reinstalled per the
original design. Be sure that the safety purpose of the polarized line plug has not
been defeated.
3. Soldering must be inspected to discover possible cold solder joints, solder
splashes, or sharp solder points. Be certain to remove all loose foreign particles.
4. Check for physical evidence of damage or deterioration to parts and components,
for frayed leads or damaged insulation (including the AC cord), and replace if
necessary.
5. No lead or component should touch a high current device or a resistor rated at 1
watt or more. Lead tension around protruding metal surfaces must be avoided.
6. After reassembly of the set, always perform an AC leakage test on all exposed
metallic parts of the cabinet (the channel selector knobs, antenna terminals,
handle and screws) to be sure that set is safe to operate without danger of electri-
cal shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS
TEST. Use an AC voltmeter having 5000 ohms per volt or more sensitivity in the
following manner: Connect a 1500 ohm, 10 watt resistor, paralleled by a .15 mfd
150V AC type capacitor between a known good earth ground water pipe, con-
duit, etc.) and the exposed metallic parts, one at a time. Measure the AC voltage
across the combination of 1500 ohm resistor and .15 mfd capacitor. Reverse the
AC plug by using a non-polarized adaptor and repeat AC voltage measurements
for each exposed metallic part. Voltage measured must not exceed 0.75 volts
RMS. This corresponds to 0.5 milliamp AC. Any value exceeding this limit consti-
tutes a potential shock hazard and must be corrected immediately.
TIPS ON PROPER INSTALLATION
1. Never install any receiver in a closed-in recess, cubbyhole, or closely fitting shelf
space over, or close to, a heat duct, or in the path of heated air flow.
2. Avoid conditions of high humidity such as: outdoor patio installations where dew
is a factor, near steam radiators where steam leakage is a factor, etc.
3. Avoid placement where draperies may obstruct venting. The customer should
also avoid the use of decorative scarves or other coverings that might obstruct
ventilation.
4. Wall- and shelf-mounted installations using a commercial mounting kit must follow
the factory-approved mounting instructions. A product mounted to a shelf or plat-
form must retain its original feet (or the equivalent thickness in spacers) to provide
adequate air flow across the bottom. Bolts or screws used for fasteners must not
touch any parts or wiring. Perform leakage tests on customized installations.
5. Caution customers against mounting a product on a sloping shelf or in a tilted
position, unless the receiver is properly secured.
6. A product on a roll-about cart should be stable in its mounting to the cart.
Caution the customer on the hazards of trying to roll a cart with small casters
across thresholds or deep pile carpets.
7. Caution customers against using extension cords. Explain that a forest of exten-
sions, sprouting from a single outlet, can lead to disastrous consequences to
home and family.

1-4
SERVICING PRECAUTIONS
CAUTION: Before servicing the Audio products covered by this
service data and its supplements and addends, read and fol-
low the SAFETY PRECAUTIONS.
NOTE: if unforeseen circumstances create conflict between
the following servicing precautions and any of the safety
precautions in this publication, always follow the safety pre-
cautions.
Remember Safety First :
General Servicing Precautions
1. Always unplug the
Audio products AC power cord from the
AC power source before:
(1) Removing or reinstalling any component, circuit board,
module, or any other assembly.
(2) Disconnecting or reconnecting any internal electrical
plug or other electrical connection.
(3) Connecting a test substitute in parallel with an electro-
lytic capacitor.
Caution: A wrong part substitution or incorrect polarity
installation of electrolytic capacitors may result in an
explosion hazard.
2. Do not spray chemicals on or near this
Audio products or any
of its assemblies.
3. Unless specified otherwise in this service data, clean elec-
trical contacts by applying an appropriate contact cleaning
solution to the contacts with a pipe cleaner, cotton-tipped
swab, or comparable soft applicator.
Unless specified otherwise in this service data, lubrication
of contacts is not required.
4. Do not defeat any plug/socket B+ voltage interlocks with
which instruments covered by this service manual might be
equipped.
5. Do not apply AC power to this
Audio products and / or any
of its electrical assemblies unless all solid state device heat
sinks are correctly installed.
6. Always connect the test instrument ground lead to an
appropriate ground before connecting the test instrument
positive lead. Always remove the test instrument ground
lead last.
Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet and turn
the power on. Connect an insulation resistance meter (500V)
to the blades of the attachment plug. The insulation resis-
tance between each blade of the attachment plug and acces-
sible conductive parts (Note 1) should be more than 1Mohm.
Note 1: Accessible Conductive Parts include Metal panels,
Input terminals, Earphone jacks,etc.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged
easily by static electricity. Such components commonly are
called Electrostatically Sensitive (ES) Devices. Examples
of typical ES 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 compo-
nent or semiconductor-equipped assembly, drain off any
electrostatic charge on your body by touching a known
earth ground. Alternatively, obtain and wear a commer-
cially 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 ES
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
ES 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 ES devices.
5. Do not use freon-propelled chemicals. These can generate
an electrical charge sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install
it. (Most replacement ES devices are packaged with leads
electrically shorted together by conductive foam, aluminum
foil, or comparable conductive material).
7. Immediately before removing the protective material from
the leads of a replacement ES device, touch the protective
material to the chassis or circuit assembly into which the
device will be installed.
Caution: Be sure no power is applied to the chassis or cir-
cuit, and observe all other safety precautions.
8.Minimize bodily motions when handling unpackaged
replacement ES devices. (Normally harmless motion such
as the brushing together of your clothes fabric or the lifting
of your foot from a carpeted floor can generate static elec-
tricity sufficient to damage an ES device.)

1-5
Ao/p"atqzrj-:Liozxyx{tqzrjqj{jq
F"Qzshynts-:^jqjhyxymjkzshynts/
1(Standby)
B"`^M-5Ntssjhyytf`^Mij{nhj/
CPORT.IN ([twyfgqj- : Ntssjhyytf[twyfgqj
ij{nhj/
DOPT. IN (Zuynhfq) : NtssjhyytfsZuynhfqij{nhj/
A
Standby LED (Red)
B
QzshyntsWPO"bmnyj-
C
]jrtyjxjsxtw
D
The buttons are located on the rear.
NAME OF EACH COMPONENT
• Front Panel
• Rear Panel
Standby LED (Red)
(Volume) : Adjusts volume level (USB) : Connect to a USB device.
PORT.IN (Portable) : Connect to a Portable
device.
device.
OPT. IN (Optical) : Connect to an Optical
(Function) : Selects the function.
(Standby)
The buttons are located on the rear.
Function LED (White)
Remote sensor

1-6
WIRELESS SUBWOOFER CONNECTION
LED indicator of wireless subwoofer
LED Color Status
Green
(Blink)
Attempting to make connection.
Green The connection is completed.
Red
The wireless subwoofer
is in standby mode
or the connection is failed.
Off
(No display)
The power cord of wireless
subwoofer is disconnected.
Setting up the wireless subwoofer
for the first time
1. Connect the power cord to the wireless subwoofer
and plug the power cord into a power outlet.
2. Turn on the main unit : The sound bar and wireless
subwoofer will be automatically connected.
- Green LED on the rear of wireless subwoofer
turns on.
Manually pairing wireless subwoofer
When your connection is not completed, you can
check red LED on the wireless subwoofer and the
wireless subwoofer does not make sound. To solve
the problem, follow the steps below.
1. Press Pairing button on the rear of the wireless
subwoofer.
- The green LED on the rear of the wireless
subwoofer blinks quickly.
2. Turn on the main unit.
3. Pairing is completed.
- The green LED on the rear of the wireless
subwoofer turns on.
Note :
•It takes a few seconds (and may take longer) for
the main unit and the subwoofer to communicate
with each other and make sounds.
• The closer the main unit and the wireless subwoofer,
the better sound quality. It is recommended to install
the main unit and the wireless subwoofer as close
as possible and avoid the cases below.
- There is an obstacle between the main unit and
the wireless subwoofer.
- There is a device using same frequency with this
wireless connection such as a medical equipment,
a microwave or a wireless LAN device.
- Keep the sound bar and the wireless subwoofer
away from the device (ex. wireless router, microwave
oven, etc.) over 1 m to prevent wireless interference.

1-7
HIDDEN KEY MODE
HIDDEN MODE KEYS
Version Check Main unit ‘–(Volume)’ + Remote control ‘ll (Play/Pause)’
Clip On/Off Main unit ‘–(Volume)’ + Remote control ‘F’
Wireless RF Main unit ‘–(Volume)’ + Remote control ‘B.Skip’
Sound BYPASS Main unit ‘–(Volume)’ + Remote control ‘AUTO POWER OFF’
TV Remote control On/Off ON: Press and hold ‘DRC ON’ on the remote control for about 2 seconds.
OFF: Press and hold ‘DRC OFF’ on the remote control for about 2 seconds.
Wireless Reset Main unit “MIN” (volume minimum state) + Remote control ‘ (Mute)’ for 3 seconds.
BT Lock On/Off ON: Press and hold ‘AUTO POWER ON’ on the remote control for about 2 seconds in BT function.
OFF:
Press and hold ‘AUTO POWER OFF’ on the remote control for about 2 seconds in BT function.
APD On/Off Main unit ‘–(Volume)’ + Remote control ‘AUTO POWER ON’
Factory Reset Main unit ‘–(Volume)’ + Remote control ‘STANDARD’
Option Edit Main unit ‘–(Volume)’ + Remote control ‘BASS BLAST’

1-8
1. Preparation
- Remote control.
- Do format USB Memory to FAT32 File system.
- USB : Update file exist only in the USB Memory stick.
Ex) SJ2 :
MCS : E:\SJ2_201701250.bin (if USB driver is E:\)
Wireless Tx E:\SJ2_Wireless_Tx_1701250 (if USB driver is E:\)
Wireless Rx E:\SJ2_Wireless_Rx_1701250 (if USB driver is E:\)
2. Update Step
2-1. Main, Tx
1) Power on.
2) Select the USB function (USB Mode).
3) Insert USB.
If find program, set will start to update automatically.
4) Each function LED Blinking is shown while updating.
Never remove USB or AC cord.
5) After update done, set will power off automatically.
2-2. Rx
1) Power on.
2) Wireless connect Main unit and Wireless subwoofer.
3) Insert USB.
If find program, set will start to update automatically.
4) Each function LED Blinking is shown while updating.
Never remove USB or AC cord.
5) After update done, set will power off automatically.
3. Version Check
1) Power on.
2) Press the Main unit ‘–(Volume)‘ + Remote control ‘ll (Play/Pause)’.
3) You can hear the voice sound in English.
Ex) D : 1701250
4) When you press the F.Skip or B.Skip button on the remote control, you can hear Tx and Rx Version.
Ex) Tx : 1701250, Rx: 1701250
5) If you don’t want version sound, please power off power on.
SOFTWARE UPDATE GUIDE

1-9
GENERAL
Power requirements Refer to the main label.
Power consumption Refer to the main label.
Dimensions (W x H x D) Approx. 660 mm x 56 mm x 99 mm with foot
Operating temperature 5 °C to 35 °C
Operating humidity 5 % to 90 %
Bus Power Supply 5 V 500 mA
Available Digital Input Audio Sampling Frequency 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz
Available Digital Input Audio format Dolby Audio, PCM
INPUTS
OPT. IN (Digital audio in) 0 dBfs, Optical jack x 1
PORT. IN (Portable in) 0.4 Vrms (3.5 mm stereo jack) x 1
AMPLIFIER (RMS Output power)
Total 160 W RMS
Front 30 W RMS x 2 (8 Ωat 1 kHz, 10 % THD)
Subwoofer 100 W RMS (3 Ωat 100 Hz, 10 % THD)
WIRELESS SUBWOOFER
Power requirements Refer to the main label on the subwoofer.
Power consumption Refer to the main label on the subwoofer.
Type 1 Way 1 Speaker
Impedance 3 Ω
Rated Input Power 100 W RMS
Max. Input Power 200 W RMS
Dimensions (W x H x D) Approx. 185.5 mm x 303 mm x 205 mm
Designs and specifications are subject to change without prior notice.
SPECIFICATIONS

1-10

2-1
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
DISASSEMBLY INSTRUCTIONS ..................................................................................................................... 2-2
1. HOW TO DISASSEMBLE THE MAIN UNIT ............................................................................................. 2-2
2. HOW TO DISASSEMBLE THE SUBWOOFER........................................................................................ 2-6
EXPLODED VIEWS ........................................................................................................................................... 2-9
1. MAIN UNIT SECTION............................................................................................................................... 2-9
2. WIRELESS SUBWOOFER SECTION.................................................................................................... 2-11
3. PACKING ACCESSORY SECTION ....................................................................................................... 2-13

2-2
DISASSEMBLY INSTRUCTIONS
1
1
2
Figure 1-1
1. HOW TO DISASSEMBLE THE MAIN UNIT
※ Before begin, position the Main Unit upside down.
1-1. Case Bottom Assembly
1) Remove the 19 screws.
2) Remove the Case Bottom Assembly.

2-3
3
4
1
1
1
1
2
Figure 1-2 (2)
Figure 1-2 (1)
HOW TO DISASSEMBLE THE MAIN UNIT
2) Remove the 2 screws.
3) Remove the Main Chassis Assembly. (Main Chassis + PCBA)
1-2. Main Chassis Assembly
1) Disconnect the 5 cables from the Main PCB Assembly and SMPS PCB Assembly.

2-4
1
1
2
3
4
2
3
1
Figure 1-2-2
Figure 1-2-1
HOW TO DISASSEMBLE THE MAIN UNIT
1-2-2. Main PCB Assembly and SMPS PCB Assembly
1) Remove the 2 screws.
2) Remove the Main PCB Assembly.
3) Remove the 2 screws.
4) Remove the SMPS PCB Assembly.
1-2-1. LED PCB Assembly
1) Disconnect the cable from the Main PCB Assembly.
2) Remove the 2 screws.
3) Remove the LED PCB Assembly.

2-5
HOW TO DISASSEMBLE THE MAIN UNIT
1
1
2
Figure 1-3
1-3. Speaker Chamber Assembly and BT module
1) Remove the Speaker Chamber Assembly.
2) Remove the BT module.

2-6
Figure 2-1 (1)
Figure 2-1 (2)
2. HOW TO DISASSEMBLE THE SUBWOOFER
2-1. Rear Panel Assembly
1) Remove the 11 screws.
2) Pull out the Rear Panel Assembly and disconnect the Speaker cable.

2-7
1
2
Figure 2-2 (1)
Figure 2-2 (2)
HOW TO DISASSEMBLE THE SUBWOOFER
2-2. SMPS & AMP PCB Assembly
1) Disconnect the Power inlet socket cable.
2) Remove the 5 screws.
3) Remove the SMPS & AMP PCB Assembly.

2-8

KEY
BT
D
LED
B
A
251
251
A42
574
574
271L
271R
573
572
572
571
573
CABLE3
CABLE2
573
573
A55
B
D
E
C
E
F
C
A
F
281
281
A52
283
CABLE1
CABLE4
CABLE4
272
A41
A43
260
261
282
A47
A46
A54
MAIN
WIRELESS
SMPS
300
2-102-9
EXPLODED VIEWS
1. MAIN UNIT 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.