LG LAS551H User manual

SERVICE MANUAL
SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS”
IN THIS MANUAL.
Internal Use Only
Website http://biz.lgservice.com
Wireless Sound Bar
JANUARY, 2015P/NO : AFN76932738
MODEL: LAS551H (LAS551H, S55A1-D)
MODEL: LAS551H
(LAS551H, S55A1-D)

1-1
CONTENTS
SECTION 1 ........ GENERAL
SECTION 2 ........ CABINET & MAIN CHASSIS
SECTION 3 ........ ELECTRICAL
SECTION 4 ........ WIRELESS SUBWOOFER PART
SECTION 5 ........ REPLACEMENT PARTS LIST

1-2
SECTION 1
GENERAL
CONTENTS
ESD PRECAUTIONS......................................................................................................................................... 1-3
WIRELESS SUBWOOFER CONNECTION....................................................................................................... 1-4
HIDDEN KEY MODE ......................................................................................................................................... 1-5
MCS / EQ HIDDEN KEY GUIDE ....................................................................................................................... 1-6
MCS / EQ PROGRAM UPDATE GUIDE........................................................................................................... 1-7
SPECIFICATIONS ............................................................................................................................................. 1-8

1-3
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.

1-4
WIRELESS SUBWOOFER CONNECTION
LED indicator of wireless subwoofer
LED Color Status
Yellow-green
(Blink) The connection is trying.
Yellow-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 of the wireless subwoofer
to the outlet.
2. Turn on the main unit : The main unit and wireless
subwoofer will be automatically connected.
Manually pairing wireless subwoofer
When your connection is not completed, you can see
the red LED or the blinking of yellow-green LED on
the wireless subwoofer and the subwoofer does not
make sound. To solve the problem, follow the below
steps.
1. Adjust volume level of the main unit to minimum.
- ”VOL MIN” appears on the display window.
2. Press and hold (Mute) on the remote control for
about 3 seconds.
- “WL RESET” appears on the display windo briefly
and Red LED on the main unit is blinking.
3. If the LED of the wireless subwoofer already blinks
in yellow-green continually, you can skip this step.
Press and hold PAIRING on the back of the
wireless subwoofer for more than 5 seconds.
- The LED of the wireless subwoofer lights up
alternately in red and yellow-green.
4. Disconnect the power cord of the main unit and the
wireless subwoofer.
5. Connect them again after the LED of the main unit
and the wireless subwoofer is fully turned off.
The main unit and the wireless subwoofer will be
paired automatically when you turn on the main unit.
- When the connection is completed, you can see
the yellow-green LED on the subwoofer.
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 subwoofer, the
better sound quality. It is recommended to install
the main unit and the subwoofer as close as
possible (within 5 m) and avoid the cases below.
- There is a obstacle between the main unit and the
subwoofer.
- There is a device using same frequency with this
wireless connection such as a medical equipment,
a microwave or a wireless LAN device.

1-5
HIDDEN KEY MODE
HIDDEN MODE KEYS
EEPROM EDIT Main set ‘-’ (Volume) + Remote control ‘OPTICAL’
EEPROM CLEAR (Initialize) Main set ‘-’ (Volume) + Remote control ‘SOUND EFFECT’
VERSION CHECK Main set ‘-’ (Volume) + Remote control ‘Play’
CLIP OFF
Main set ‘-’ (Volume) + Remote control ‘FUNC’ (Function)CLIP ON
CLIP ON GAIN MONITERING
MAX VOLUME EDIT
ENTRANCE KEY : Main set ‘-’ (Volume) + Remote control ‘SLEEP’
SETTING KEY : VOL +/-
EXIT KEY : Play/Pause
CLIP ALGORITHM EDIT Main set ‘-’ (Volume) + Remote control ‘VOL -’
WIRELESS RF CHANNEL CHANGE Main set ‘-’ (Volume) + Remote control ‘INFO’
SOUND BYPASS Main set ‘-’ (Volume) + Remote control ‘DRC’
APD TIME DISPLAY Main set ‘-’ (Volume) + Remote control ‘AV SYNC’
UP REPEAT (Up)
DOWN Stop/Ok (Down)
RIGHT F.Skip (Right)
LEFT B.Skip (Left)
ENTER Play/Pause (Enter)
DEMO MODE Main set ‘F’ (Function) + Remote control ‘OPTICAL’
WIRELESS FACTORY Main set “VOL MIN” (volume minimum state) + Remote control ‘Mute’
for 5 seconds.

1-6
1. Version & Option Check
1) Power on.
2) Press main set "-" (volume -) key and remote control " " (Play/Pause) key during 3 seconds.
3) Check MCS version.
Ex)
4) Press remote control (" ") key 1 time.
Check Wireless Tx version.
Ex)
5) Press remote control (" ") key 1 time.
Check Wireless Rx version.
It’s possible to connect wireless subwoofer.
Ex)
6) Press remote control (" ") key 1 time.
Check EQ version.
Ex)
7) Press remote control (" ") key 1 time.
Check option.
Press remote control " "/ " "/ " " key.
Previous / Next option.
Ex)
8) Power cord unplug.
2. EEPROM Initialize
1) Power on.
2) Press main set “-” (volume -) key and remote control “SOUND EFFECT” during 3 seconds.
3) Display VFD “E2P CLR”.
4) Power off automatically.
5) Power cord unplug.
MCS / EQ HIDDEN KEY GUIDE
P1411182
TX150303
RX000000
Q1411170
OP00-00

1-7
1. Preparation
- Remote control.
- Do format USB Memory to FAT32 File system.
- USB : Update file exist only in the USB Memory stick.
Ex ) LAS550H :
MCS E:\PG540_FW_LAS550H_Ver.bin (if USB driver is E:\)
EQ E:\EQ_PRG.BIN (if USB driver is E:\)
Wireless Tx E:\WIRELESS_TX_150011.bin (if USB driver is E:\)
Wireless Rx E:\WIRELESS_RX_150303.bin (if USB driver is E:\)
2. Update
1) Power on.
2) Change the USB function.
3) Insert USB.
4) Display in VFD.
MCS : “MCS UP” “FINISH” Power off.
EQ : “EQ UP” “FINISH” Power off.
Wireless Tx : “UPDATE” “WR XX”(Progress) “FINISH” Power off.
Wireless Rx : “UPDATE” “SEND XX”(Progress) “FINISH” Power off.
5) Loading is shown while updating.
Never remove USB or AC cord.
6) After update finish, show FINISH in VFD and power of automatically.
7) Power cord un-plug.
MCS / EQ PROGRAM UPDATE GUIDE


1-8
SPECIFICATIONS
• GENERAL (LAS551H)
Power requirements 120 V ~ 60 Hz
Power consumption 27 W
Networked standby : 2.5 W (If all network ports are activated.)
Dimensions (W x H x D) 890 mm x 51 mm x 85 mm (31.8 inch x 2.0 inch x 3.3 inch)
Net Weight (Approx.) 2.8 kg (6.2 lb)
Operating temperature 41 °F to 95 °F (5 °C to 35 °C)
Operating humidity 5 % to 90 %
• INPUT/OUTPUT
OPT. IN 3 V (p-p), Optical jack x 1
PORT. IN 0.5 Vrms (3.5 mm stereo jack) x 1
HDMI IN 19 Pin (Type A, HDMI™ connector) x 1
HDMI OUT 19 Pin (Type A, HDMI™ connector) x 1
Available Digital Input Audio
Sampling Frequency 32 kHz, 44.1 kHz, 48 kHz, 96 kHz
• USB
Version 2.0
Bus Power Supply 5 V 500 mA
• AMPLIFIER
Total 320 W
Front Middle/ Tweeter 40 W x 2 (4 Ωat 1 kHz) / 20 W x 2 (8 Ωat 12 kHz)
Subwoofer 200 W (3 Ωat 80 Hz)
THD 10 %
• WIRELESS SUBWOOFER (S55A1-D)
Power requirements 120 V ~ 60 Hz
Power consumption 33 W
Type 1 Way 1 Speaker
Impedance 3 Ω
Rated Input Power 200 W
Max. Input Power 400 W
Dimensions (W x H x D) 171 mm x 390 mm x 261mm (6.7 inch x 15.3 inch x 10.2 inch)
Net Weight (Approx.) 5.6 kg (12.3 lb)
• BLUETOOTH
Codec SBC
•Designs and specifications are subject to change without prior notice.

2-1
SECTION 2
CABINET & MAIN CHASSIS
CONTENTS
DISASSEMBLY INSTRUCTIONS ..................................................................................................................... 2-2
EXPLODED VIEWS ........................................................................................................................................... 2-5
1. MAIN SET SECTION ................................................................................................................................ 2-5
2. WIRELESS SUBWOOFER SECTION...................................................................................................... 2-7
3. PACKING ACCESSORY SECTION ......................................................................................................... 2-9

2-2
DISASSEMBLY INSTRUCTIONS
Before you begin, position the main set upside down.
1. Case Bottom Assembly
1) Remove the 18 screws on the main set.
2) Remove the Case Bottom Assembly.
2. Deco Side
1) Remove the 4 screws securing the Deco Side.
2) Remove the Deco Side (left/ right).
Fig. 2
Fig. 1
1
1
23
Deco Side
2
1
Case Bottom Assembly

2-3
4. Bluetooth Module
1) Disconnect the FFC cable from the Bluetooth Module.
2) Remove the Bluetooth Module.
3) Check and Replace the Bluetooth Module.
3. Grille
1) Remove the Grille.
Fig. 4
Fig. 3
1
2
Bluetooth Module

2-4
5. Tack Key Board
1) Remove the 2 screws securing the Cover Button Assembly.
2) Remove the Cover Button Assembly (Cover Button + Holder Button).
3) Remove the Tack Key Board.
4) Disconnect the Harness cable from the Tack Key Board.
5) Check and Replace the Tack Key Board.
Fig. 5
1
2
3
4
Tack Key Board
Cover Button
Cover Button
Assembly
Holder Button

G
300
C
D
E
AB
G
F
C
D
E
FB
A
254
254
264
464
468
A44A
464
251
464
A47
A46
A54
A42
A43
253
464
464
A52
262
A48
252
CABLE2
CABLE3
FRONT
HDMI &
JACK
WIRELESS B/T
A55
260
261
KEY
MAIN
SMPS
457
A44B
257
258
258
257
464
464
464
255
263
SPK703
SPK704
263
464
464
EXPLODED VIEWS
1. MAIN SET 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.

A
D
E
WIRELESS
SMPS
AMP
B
A
E
D
B
C
C
A900
950
951
956
954
955
956
956
A900W
300W
A45W
A54W
A47W
952
CN901
953
A49W
2. WIRELESS SUBWOOFER 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.

803 Packing, Main
806 Optical cable
801 Owner’s manual
900 Remote control
804 Bag
802 Box
829 Cable tie
837 Cover foot (2)
808 Batteries (2)
835 Wall bracket 836 Screws (2)
3. PACKING ACCESSORY SECTION

2-10

3-1
SECTION 3
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM (PVDD) ............................................................................................................ 3-2
2. POWER ON ERROR .............................................................................................................................. 3-3
3. NO SOUND (PORTABLE FUNCTION) .................................................................................................. 3-4
4. NO WIRELESS ....................................................................................................................................... 3-5
5. NO BLUETOOTH.................................................................................................................................... 3-6
6. NO SOUND (USB).................................................................................................................................. 3-7
7. NO SOUND (OPTICAL).......................................................................................................................... 3-8
8. HDMI PROBLEM .................................................................................................................................... 3-9
WAVEFORMS OF MAJOR CHECK POINT.................................................................................................... 3-10
1. CRYSTAL.............................................................................................................................................. 3-10
2. FLASH MEMORY ................................................................................................................................. 3-11
3. TACT KEY............................................................................................................................................. 3-12
4. USB....................................................................................................................................................... 3-13
5. REMOTE CONTROL ............................................................................................................................ 3-14
6. OPTICAL............................................................................................................................................... 3-15
7. PORTABLE ........................................................................................................................................... 3-16
8. AUDIO PWM ......................................................................................................................................... 3-17
9. AUDIO AMP .......................................................................................................................................... 3-19
WIRING DIAGRAM.......................................................................................................................................... 3-21
BLOCK DIAGRAM .......................................................................................................................................... 3-23
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-25
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-25
2. MAIN - DSP CIRCUIT DIAGRAM......................................................................................................... 3-27
3. MAIN - PWM & AMP CIRCUIT DIAGRAM ........................................................................................... 3-29
4. MAIN - POWER CIRCUIT DIAGRAM................................................................................................... 3-31
5. HDMI & JACK CIRCUIT DIAGRAM...................................................................................................... 3-33
6. FRONT CIRCUIT DIAGRAM ................................................................................................................ 3-35
7. TACT KEY CIRCUIT DIAGRAM ........................................................................................................... 3-37
CIRCUIT VOLTAGE CHART........................................................................................................................... 3-39
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-41
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-41
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-43
3. HDMI & JACK P. C. BOARD DIAGRAM .............................................................................................. 3-45
4. FRONT P. C. BOARD DIAGRAM......................................................................................................... 3-45
5. TACT KEY P. C. BOARD DIAGRAM.................................................................................................... 3-45

3-2
ONE POINT REPAIR GUIDE
1. NO POWER PROBLEM (PVDD)
No power problem occurs when you power on the unit
1-1. Solution
Replace SMPS board.
1-2. How to troubleshoot (Countermeasure)
1) Check the PVDD voltage 18.7 V at pin1, 2, 3.
When you check the no power at this point, then replace SMPS board.
1-3. Service hint (Any picture / Remark)
< MAIN board top view >
PVDD
PVDD

3-3
ONE POINT REPAIR GUIDE
2. POWER ON ERROR
No display or Not working.
2-1. IC601
1) Check 3.3 VA at L602.
2) If 3.3 VA is not checked at the point, then find 18.7 V at pin7 of IC601.
3) 1), 2) is NG. Replace IC601.
2-2. IC602
1) Check 5.1 VA at L606.
2) If 5.1 VA is not checked at the point, then find 18.7 V at pin7 of IC602.
3) 1), 2) is NG. Replace IC602.
2-3. IC603
1) Check 12 VA at L604.
2) If 12 VA is not checked at the point, then find 18.7 V at pin7 of IC603.
3) 1), 2) is NG. Replace IC603.
< MAIN board top view >
< MAIN board top view >
< MAIN board top view >
L602
L602
L606
L606
L604
L604
IC601 pin7
IC601 pin7
IC602 pin7
IC602 pin7
IC603 pin7
IC603 pin7