LG SJ4Y Service Manual
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LG SJ4Y Service Manual

Wireless sound bar
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CONFIDENTIAL
Wireless Sound Bar
SERVICE MANUAL
MODEL: SJ4Y
(SJ4Y, SPJ4B-W)
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS"
IN THIS MANUAL.
P/NO : AFN78302533
FEBRUARY, 2019
Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved.
Only for training and service purposes.

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  • Page 1 SERVICE MANUAL MODEL: SJ4Y (SJ4Y, SPJ4B-W) CAUTION BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL. P/NO : AFN78302533 FEBRUARY, 2019 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 2 SECTION 2 ..CABINET & MAIN CHASSIS SECTION 3 ..ELECTRICAL SECTION 4 ..WIRELESS SUBWOOFER PART SECTION 5 ..WIRELESS RECEIVER PART (OPTION) Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 3: Table Of Contents

    REAR SPEAKERS CONNECTION (SOLD SEPARATELY) ................1-6 ABOUT LED CONDITION ..........................1-7 HIDDEN KEY MODE ............................1-8 SOFTWARE UPDATE GUIDE ........................... 1-9 SPECIFICATIONS ............................1-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 4: Esd Precautions

    THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE LITERATURE. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 5: Name Of Each Component

    A o/p : B DC IN : C OPTICAL IN : D PORTABLE IN : E USB F HDMI OUT (TV ARC) / IN : Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 6: Wireless Subwoofer Connection

    2. Turn on the main unit. 3. Pairing is completed. - The green LED on the rear of the wireless subwoofer turns on. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 7: Rear Speakers Connection (Sold Separately)

    + to + and – to –. If the cables are reversed, the sound will be distorted and will lack bass. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 8: About Led Condition

    Condition Description USB LED blinks. BT (Bluetooth Bluetooth BT (Bluetooth) LED blinks. Bluetooth HDMI IN USB and BT (Bluetooth) LEDs Note LED (Red) Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 9: Hidden Key Mode

    Display window : “ON - BT LOCK” <=> “OFF - BT LOCK” Wireless Factory Main unit “MIN” (volume minimum state) + Remote control ' (Mute)' for about 3 seconds. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 10: Software Update Guide

    2) Select the USB function. 3) Insert USB. 4) Never remove USB or AC cord while updating. 5) After update fi nish, power will be off automatically. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 11 2. Using APP (FOTA : Firmware update Over The Air) 2-1. Run BT App (Music Flow Bluetooth) 2-2. Connect Bluetooth Menu button Connection button < Not Connected > < Connected > 1-10 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 12 • Some Country(ex China) can not access to CDN Server. And can not use FOTA. So, This Button can not enable in that country. 1-11 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 13 Using APP (FOTA : Firmware update Over The Air) 2-4-2. FOTA Start Button 2-5. FOTA Caution button FOTA Start button < Internet Connected > 1-12 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 14 2-7. FOTA - OPP Download Cancel Cancel button button Cancel Button is available Cancel Button is not available When CDN downloading. When OPP downloading. 1-13 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 15 2-8. FOTA - Write Flash 2-9. FOTA - Finish Power cable reconnect. Cancel button Cancel Button is not available When Flash writing. 1-14 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 16: Specifications

    Approx. 88 mm x 122 mm x 81 mm (3.46 inches x 4.8 inches x 3.18 inches) • Designs and specifications are subject to change without prior notice. 1-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 17 1-16 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 18 2. HOW TO DISASSEMBLE THE WOOFER ....................2-8 EXPLODED VIEWS ............................2-11 1. MAIN UNIT SECTION ..........................2-11 2. WIRELESS SUBWOOFER SECTION ....................2-13 3. PACKING ACCESSORY SECTION ....................... 2-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 19: Disassembly Instructions

    2) Remove the Case Bottom Assembly. 3) Remove the 2p harness cable (key) connected to the MAIN PCB Assembly. Case Bottom Assembly Figure 1-1 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 20: How To Disassemble The Main Unit

    Figure 1-2 (1) 2) Remove the screw. 3) Remove the Main Frame Assembly (Main Chassis + PCBA). Main Frame Assembly Figure 1-2 (2) Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 21 2) Disconnect the FFC cables from the Main PCB. 3) Remove the 3 screws (Main + HDMI Jack). 4) Remove the Main PCB Assembly. Main Chassis Main PCB Assembly Figure 1-2-2 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 22 5) Remove the WIRELESS module. 6) Disconnect the FFC cable from the WIRELESS module. 7) Remove the WIRELESS module. WIRELESS Module BT Module WIRELESS Module Figure 1-2-3 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 23 Speaker Chamber Left Assembly Figure 1-3 1-4. KEY PCB Assembly 1) Remove the 2 screws. 2) Remove the Key PCB Assembly. Key PCB Assembly Figure 1-4 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 24 Figure 1-5 (1). < Speaker network cable from SPK Chamber L/R Assembly to MAIN PCB > Figure 1-5 (2). < Harness cable from KEY PCB to MAIN PCB > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 25 Figure 2-1 (1) 2) Pull out the Rear Panel Assembly and disconnect the SPK cable. Rear Panel Assembly SPK cable Figure 2-1 (2) Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 26: How To Disassemble The Woofer

    2) Assemble the WIRELESS module into the wireless holder. 3) Attach the EVA sheet (0.15T) to the WIRELESS module. 4) Connect the FFC cable. Figure 2-2 (2) Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 27 AMP+SMPS PCB Assembly Figure 2-3 (1) 2) Remove the 5 screws. 3) Remove the AMP+SMPS PCB Assembly. AMP+SMPS PCB Assembly Figure 2-3 (2) 2-10 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 28: Exploded Views

    EXPLODED VIEWS 1. MAIN UNIT SECTION A80R CABLE1 MAIN 271R FRONT CABLE2 CABLE3 WIRELESS WIRELESS CABLE4 A80L 271L 2-11 2-12 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 29: Wireless Subwoofer Section

    2. WIRELESS SUBWOOFER SECTION A900 A900W A45W A54W 2-13 2-14 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 30: Packing Accessory Section

    3. PACKING ACCESSORY SECTION 806 Optical cable 900 Remote control 300 Power cord 833 AC adapter 836 Screws (2) 835 Wall bracket 2-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 31 2-16 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 32 1. MAIN P. C. BOARD DIAGRAM ......................3-25 2. FRONT P. C. BOARD DIAGRAM ......................3-27 3. KEY P. C. BOARD DIAGRAM ......................3-27 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 33: Wiring Diagram

    WIRING DIAGRAM CN704 CN703 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 34: Block Diagrams

    BLOCK DIAGRAMS 1. SYSTEM BLOCK DIAGRAM Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 35: Power Block Diagram

    2. POWER BLOCK DIAGRAM Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 36: One Point Repair Guide

    1-1-3. Service hint (Any picture / Remark)   IC302 IC302     L302 L302 IC302 IC302   < MAIN board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 37 1-2-3. Service hint (Any picture / Remark)   IC301 IC301 IC301 IC301   L301 L301 < MAIN board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 38 3) If 3.3 VA, 5 V OK, replace FRONT board. 1-3-3. Service hint (Any picture / Remark)         < FRONT board bottom view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 39: Sound

    If no signal, please replace MAIN board. 2-1-3. Service hint (Any picture / Remark)   CN102 CN102   CN102 CN102 < MAIN board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 40 2-2-3. Service hint (Any picture / Remark)         R209 R209 C208 C208 < MAIN board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 41 2) If soldering status and 5.1 VA are abnormal, replace MAIN board. 2-3-3. Service hint (Any picture / Remark)     IC308 IC308 < MAIN board bottom view > 3-10 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 42 2-4-3. Service hint (Any picture / Remark)       IC201 IC201   < MAIN board top view > 3-11 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 43 2-5-3. Service hint (Any picture / Remark)         FB201 FB201 < MAIN board top view > 3-12 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 44: Protection Error

    3-1-3. Service hint (Any picture / Remark) AR601 AR601 CN703 CN703 IC600 IC600 AR602 AR602 CN704 CN704 < MAIN board top view > 3-13 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 45 4) If check point 1), 2), 3) is ok, replace MAIN board. 3-2-3. Service hint (Any picture / Remark) IC701 IC701 IC700 IC700 < MAIN board bottom view > 3-14 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 46 2) If 12 V is OK, replace MAIN board. 3-3-3. Service hint (Any picture / Remark) IC701 IC701 IC700 IC700 < MAIN board bottom view > 3-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 47: Waveforms Of Major Check Point

    WAVEFORMS OF MAJOR CHECK POINT 1. CRYSTAL FIG 1-1. X501 (27 MHz) FIG 1-2. X600 (24.576 MHz) 2. FLASH MEMORY FIG 2. VCC, CS#, CLK, DO 3-16 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 48: Tact Key

    FIG 3-2. Press FUNC Key FIG 3-1. Press Power Key 0.424 ~ 0.485 V FIG 3-3. Press VOL - Key FIG 3-4. Press VOL + Key 3-17 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 49: Usb

    4. USB FIG 4-1. 5 V Voltage FIG 4-2. USB D+ FIG 4-3. USB D- 3-18 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 50: Remote Control

    “ Low” Timing 4.4 ms 3.6 ms ~ 5.04 ms “ High” Timing 4.48 ms 4.08 ms ~ 5.04 ms FIG 5-3. High Timing 3-19 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 51: Optical

    6. OPTICAL FIG 6-1. OPT_IN FIG 6-2. OPT_DET 3-20 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 52: Portable

    7. PORTABLE FIG 7-1. ADC IC 5 V FIG 7-2. ADC IC 3.3 V 1 1 .27 Vrms FIG 7-3. Analog Input Voltage 3-21 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 53 3-22 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 54: Circuit Voltage Chart

    7.8 V 4.2 V ~ 17 V 12.1 V IC803 IC,DC,DC Converter 125 °C 0.8 V ~ 10 V 5.17 V 3-23 3-24 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 55: Printed Circuit Board Diagrams

    PRINTED CIRCUIT BOARD DIAGRAMS 1. MAIN P. C. BOARD DIAGRAM (TOP VIEW) (BOTTOM VIEW) 3-25 3-26 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 56: Front P. C. Board Diagram

    2. FRONT P. C. BOARD DIAGRAM (TOP VIEW) (BOTTOM VIEW) 3. KEY P. C. BOARD DIAGRAM (TOP VIEW) (BOTTOM VIEW) 3-27 3-28 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 57 3-29 3-30 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 58 6. LED ............................... 4-11 CIRCUIT VOLTAGE CHART ........................... 4-13 PRINTED CIRCUIT BOARD DIAGRAMS ....................... 4-15 1. WOOFER SMPS & AMP P. C. BOARD ....................4-15 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 59: Wiring Diagram

    WIRING DIAGRAM 2P, 3.96mm ST, Non Lock SMD Wireless 26P, 0.5mm ST, Non Lock SMD 2P, 3.96mm ST, Non Lock , SMD Power Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 60: Block Diagram

    BLOCK DIAGRAM Wireless LED (RED, GREEN) Wireless AMP_PDN AMP_SD PAIRING Reset KEY SW+/SW- PWM IC AMP IC Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 61: One Point Repair Guide

    If you can’t check 12 VA voltage, refer to the step 1-1. WL707 WL707 WIC705 WIC705 < Woofer SMPS & AMP board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 62 3) 1), 2) is NG  Replace WIC703. If you can’t check PVDD voltage, then replace the PCB board. WIC703 WIC703 < Woofer SMPS & AMP board bottom view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 63: Wireless Connection

     The main set and the wireless subwoofer are factory reset mode, then power on. WFB604 WFB604 Wireless module Wireless module Connection check Connection check < Woofer SMPS & AMP board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 64: Waveforms Of Major Check Point

    WAVEFORMS OF MAJOR CHECK POINT 1. CRYSTAL FIG 1. WX601 (24.576 MHz) 2. FLASH MEMORY FIG 2. VCC, CS#, CLK, DO Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 65: Voltage

    3. VOLTAGE FIG 3-2. Woofer 12 VA FIG 3-1. Woofer PVDD FIG 3-3. Woofer 3.3 VA FIG 3-4. Woofer 3.3V_PWM Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 66: Amp Voltage

    4. AMP VOLTAGE FIG 4-2. AMP_12V FIG 4-1. AMP PVDD Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 67: Pwm

    5. PWM FIG 5-2. Woofer PWM SW- Signal FIG 5-1. Woofer PWM SW+ Signal 4-10 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 68: Led

    6. LED FIG 6-2. Pairing On Status  Green LED FIG 6-1. Pairing Off Status  Red LED 4-11 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 69 4-12 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 70: Circuit Voltage Chart

    12.52 V 4.5 V ~ 17 V WIC705 DC,DC Converter VOUT: SW: #2 3.42 V 3.42 V 0.76 V ~ 7 V 4-13 4-14 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 71: Printed Circuit Board Diagrams

    1. WOOFER SMPS & AMP P. C. BOARD (TOP VIEW) (BOTTOM VIEW) NOTE) Warning Parts that are critical with respect to risk of fire or electrical shock. 4-15 4-16 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 72 PRINTED CIRCUIT BOARD DIAGRAMS ......................5-9 1. WIRELESS RECEIVER SMPS P. C. BOARD ..................5-9 2. WIRELESS RECEIVER AMP P. C. BOARD ..................5-11 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 73: Wiring Diagram

    WIRING DIAGRAM Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 74: Block Diagram

    BLOCK DIAGRAM Wireless LED (RED, GREEN) Wireless AMP_PDN AMP_SD PAIRING R R eset KEY RL+,-/RR+,- PWM IC Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 75: One Point Repair Guide

    Check 3.3 V. Replace AMP board. 2-3. Service hint (Any picture / Remark) RIC308 RIC308 RIC308 RIC307 RIC307 RIC307 < AMP board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 76 Check Module or connection. Replace AMP board. 3-3. Service hint (Any picture / Remark) RIC308 RIC308 RIC308 RIC307 RIC307 RIC307 < AMP board top view > Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 77: Electrical Troubleshooting Guide

    (RCN301 pin9, 10) no output. AMP 12 V (RIC308 pin4) Check RIC308. no output. 3.3 V (RIC307 pin3) Check RIC307. no output. Check Module or Connection. Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 78: Waveforms

    WAVEFORMS 1. AUDIO PART (I2S) RCN303 pin1 : I2S LRCK RCN303 pin3 : I2S BCK RCN303 pin20 : I2S Audio Data Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 79 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 80: Printed Circuit Board Diagrams

    1. WIRELESS RECEIVER SMPS P. C. BOARD (TOP VIEW) (BOTTOM VIEW) NOTE) Warning Parts that are critical with respect to risk of fire or electrical shock. 5-10 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 81: Wireless Receiver Amp P. C. Board

    2. WIRELESS RECEIVER AMP P. C. BOARD (TOP VIEW) (BOTTOM VIEW) 5-11 5-12 Copyright © 2017 - 2019 LG Electronics Inc. All rights reserved. Only for training and service purposes.

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