LG RAT376B Service Manual
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LG RAT376B Service Manual

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Internal Use Only
Website http://biz.lgservice.com
Mini Hi-Fi System
SERVICE MANUAL
MODEL: RAT376B
(RAS376BF/W)
CAUTION
BEFORE SERVICING THE UNIT, READ THE "SAFETY PRECAUTIONS"
IN THIS MANUAL.
P/NO : AFN74972241
JANUARY, 2011

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  • Page 1 Internal Use Only Website http://biz.lgservice.com Mini Hi-Fi System SERVICE MANUAL MODEL: RAT376B (RAS376BF/W) CAUTION BEFORE SERVICING THE UNIT, READ THE “SAFETY PRECAUTIONS” IN THIS MANUAL. P/NO : AFN74972241 JANUARY, 2011...
  • Page 2 CONTENTS SECTION 1 ..GENERAL SECTION 2 ..CABINET & MAIN CHASSIS SECTION 3 ..ELECTRICAL SECTION 4 ..REPLACEMENT PARTS LIST...

  • Page 3: Table Of Contents

    SECTION 1 SUMMARY CONTENTS SERVICING PRECAUTIONS ........................1-3 ESD PRECAUTIONS ..........................1-5 SERVICE INFORMATION FOR EEPROM ..................1-6 PROGRAM DOWNLOAD GUIDE ......................1-7 SPECIFICATIONS ............................1-9...

  • Page 4: Servicing Precautions

    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.

  • Page 5: Opt2

    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.

  • Page 6: Esd Precautions

    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.

  • Page 7: Service Information For Eeprom

    SERVICE INFORMATION FOR EEPROM POWER ON FLD no disc status or AUX status. Remote control ‘2’ + Front ‘STOP’ DETECT NEW EEPROM push same timing during 5 seconds. (OPTION EDIT SCREEN) NAME OPT0 FLD ‘OP-0…. OPT1 OPT2 OPT3 OPT4 Move to appropriate position and OPT5 make changes with remote control OPT6...

  • Page 8: Program Download Guide

    PROGRAM DOWNLOAD GUIDE 1. AUDIO PROGRAM Download program file name must be RAT376.HEX If security program (Water Wall) is activated on your PC, you must save the file to the USB storage device and disable the security software, then download the file to your set. Caution: When downloading the file, you should neither unplug the USB device, change to the other function, nor power off the device.
  • Page 9 2. CD PROGRAM Download program file name must be HB001_DATE_00.BIN If security program (Water Wall) is activated on your PC, you must save the file to the USB storage device and disable the security software, then download the file to your set. Caution: When downloading the file, you should neither unplug the usb device, change to the other function, nor power off the device.

  • Page 10: Specifications

    SPECIFICATIONS • GENERAL Power supply Refer to main label. Power consumption Refer to main label. Net Weight 3.4 kg External dimensions (W x H x D) 202 x 307 x 297.5 mm (without foot) BUS power supply (USB) DC 5 V 500 mA Operating conditions Temperature 5 °C ~ 35 °C (41 °F to 95 °F)
  • Page 11 MEMO 1-10...
  • Page 12 SECTION 2 CABINET & MAIN CHASSIS CONTENTS EXPLODED VIEWS ............................. 2-3 1. CABINET AND MAIN FRAME SECTION (RAT376) ................2-3 2. MECHANISM DECK SECTION (CDM-345) ..................... 2-5 3. PACKING ACCESSORY SECTION ......................2-7 4. SPEAKER SECTION ..........................2-8...
  • Page 13 MEMO...

  • Page 14: Exploded Views

    EXPLODED VIEWS 1. CABINET AND MAIN FRAME SECTION (RAT376) NOTES) THE EXCLAMATION POINT WITHIN AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT THE SERVICE PERSONNEL TO THE PRESENCE OF IMPORTANT SAFETY INFORMATION IN SERVICE 260L LITERATURE. FRONT SMPS CABLE2 MAIN 260R...

  • Page 15: Mechanism Deck Section (Cdm-345)

    MEMO 2. MECHANISM DECK SECTION (CDM-345)

  • Page 16: Packing Accessory Section

    3. PACKING ACCESSORY SECTION 824 AM Loop Antenna 801 Instruction Ass'y 825 FM Wire Antenna 808 Battery 900 Remote Control 803 Packing 804 Bag 802 Box...

  • Page 17: Speaker Section

    4. SPEAKER SECTION 4-1. FRONT SPEAKER (RAS376BF)
  • Page 18 4-2. PASSIVE SUBWOOFER (RAS376BW)
  • Page 19 MEMO 2-10...
  • Page 20 SECTION 3 ELECTRICAL CONTENTS ONE POINT REPAIR GUIDE ........................3-2 1. NO POWER ............................3-2 2. NO BOOTING WHEN POWER ON THE SET ..................3-4 3. VFD IS NOT DISPLAYED WHEN POWER ON THE SET ..............3-5 4. NO OPERATION OF MD ........................3-6 5.

  • Page 21: One Point Repair Guide

    ONE POINT REPAIR GUIDE 1. NO POWER If the unit doesn’t work by no power problem, repair the set according to the following guide. 1-1. FUSE & BRIDGE DIODE 1-1-1. Solution Please check and replace F901, BD901, TH901 on SMPS board. 1-1-2.
  • Page 22 ONE POINT REPAIR GUIDE NO POWER If the unit doesn’t work by no power problem, repair the set according to the following guide. 1-2. D929 1-2-1. Solution Please check and replace D929 on SMPS board. 1-2-2. How to troubleshoot (Countermeasure) 1) Check the Anode-Cathod Voltage of D929 with a digital multi-meter, it is normally 0.2 ~ 0.3 V.

  • Page 23: No Booting When Power On The Set

    ONE POINT REPAIR GUIDE 2. NO BOOTING WHEN POWER ON THE SET The set doesn’t work when press the power button on the front board or the remote control. 2-1. FLASH MEMORY 2-1-1. Solution Please check and replace IC101 on MAIN board. 2-1-2.

  • Page 24: Vfd Is Not Displayed When Power On The Set

    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 3-1-1. Solution Please check and replace DIG502 on FRONT board. 3-1-2.
  • Page 25 ONE POINT REPAIR GUIDE 4. 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.

  • Page 26: No Operation Of Md

    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.
  • Page 27 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.
  • Page 28 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.
  • Page 29 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.
  • Page 30 ONE POINT REPAIR GUIDE 5. NO SOUND There is no sound output in the CD FUNCTION, repair the set according to the follow- ing guide. 5-1. IN THE CD FUNCTION 5-1-1. Solution Please check and replace IC602, IC801 on MAIN board. 5-1-2.

  • Page 31: No Sound

    ONE POINT REPAIR GUIDE NO SOUND There is no sound output by DIGITAL AUDIO AMP DAMAGE, repair the set according to the following guide. 5-2. BY DIGITAL AUDIO AMP DAMAGE (IN ALL FUNCTIONS) 5-2-1. Solution Please check and replace IC700, IC701(Only RAT376) on MAIN board. 5-2-2.
  • Page 32 ONE POINT REPAIR GUIDE NO SOUND There is no sound output in the USB FUNCTION, repair the set according to the fol- lowing guide. 5-3. IN THE USB FUNCTION 5-3-1. Solution Please check and replace IC801 on MAIN board & IC505 on USB board. 5-3-2.
  • Page 33 ONE POINT REPAIR GUIDE NO SOUND There is no sound output in the AUX FUNCTION, repair the set according to the fol- lowing guide. 5-4. IN THE AUX FUNCTION 5-4-1. Solution Please check and replace IC401 on MAIN board. 5-4-2. How to troubleshoot (Countermeasure) 1) Check AUX_L/R signals to IC401 (Pin7, 8).
  • Page 34 ONE POINT REPAIR GUIDE NO SOUND There is no sound output in the TUNER FUNCTION, repair the set according to the following guide. 5-5. IN THE TUNER FUNCTION 5-5-1. Solution Please check and replace IC401, TU100 on MAIN board. 5-5-2. How to troubleshoot (Countermeasure) 1) Check if TUNER_LR is entered from Pin1,3 of TU100 to IC401(Pin23, 24).

  • Page 35: Audio Electrical Troubleshooting Guide

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 1. POWER (SMPS) No 3.7 VA Is F901 normal? Replace F901 (Use the same fuse). Is BD901 normal? Replace BD901. Is TH901 normal? Replace TH901. Is Vcc (10 V ~ 18 V) supplied to Is D904 normal? IC901 Pin7? Check or replace D904.
  • Page 36 AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE No PVDD Is F901 normal? Replace F901 (Use the same fuse). Is BD901 normal? Replace BD901. Is TH901 normal? Replace TH901. Is Vcc (10 V ~ 18 V) supplied to Is D905 normal? IC902 Pin7? Check or replace D905. Is Q910 base "H"? •...
  • Page 37 AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE No 12 V Is Vcc Check or replace D921. (15 V) supplied to Q953 collector? Is the Check P-CTRL “H” signal 13 V Supplied to Q953 from μ-COM. base? Check or replace Q953. No 5 V Is Vcc Check or replace D923.
  • Page 38 AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE No VFD Check or replace D925. Is D925 normal? Check or replace ZD951. Is ZD951 normal? Is Q951 normal? Check or replace Q951. Check or replace VFD. 3-19...

  • Page 39: Μ-Com Part Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 2. μ-COM PART CHECK μ-COM PART CHECK Check if Refer to voltage of CN105 Pin10 SMPS troubleshooting. is 3.7 VA. Check Check if output of both end voltage of D105(MBR0540) is 3.7 V. D102, D105. Check if IC102_Pin49 and Check D102, D105.

  • Page 40: Fld Display Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 4. FLD DISPLAY CHECK FLD DISPLAY CHECK Check CN104 Pin1,2,3 input Refer to SMPS troubleshooting. voltage. Check if both end voltage of F1,F2 are over 3.4 V VKK : over 26 V. Check CN304 connection and power Check CN304 connection.

  • Page 41: Pwm Modulation Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 5. PWM MODULATION CHECK PWM MODULATION PART CHECK Check Refer to CN105 Pin10 3.7 VA. SMPS troubleshooting. • Check IC602(PS9850) VDD 3.3 V (Pin16,24,29,32,35,40,48,61,64) • Check VDD Core 1.2 V (Pin1,21,43,57,59,60) • Check X602(19.2 MHz) Check Check X602 X602(19.2 MHz) Replace X602(19.2 MHz).
  • Page 42 AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE Check Check IC602(PS9850) Refer to CD Assy communication input data CD troubleshooting. Pin4, 5, 6. Pin4, 5, 6 PWM wave. Check Check each line IC602(PS9850) input resistor output. data. Check Check modulator output Replace IC602(PS9850). IC602(PS9850). FL: Pin31(+),30(-) FR: Pin28(+),27(-) and others.

  • Page 43: Power Amp Part Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 6. POWER AMP PART CHECK POWER AMP PART CHECK Check CN105 Pin2: +12 V Refer to SMPS troubleshooting. Pin13,15: 29 V. Check IC700, IC701 Pin30,31,38,39,42,43,50,51 input voltage. Check each IC603 Check each line resistor output voltage. Pin64:+12 V input.

  • Page 44: Tuner / Aux Function Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 7. TUNER / AUX FUNCTION CHECK FUNCTION CHECK Check IC401 (CS5346) Pin7,8, Check JK401,TU100. 23,24 input. Check IC401 Check IC401 Check CN105 Pin7: +5 V Pin5: +5 V (CS5346) Pin9 output Pin9,10: +3.3 V. Pin46: +3.3 V. data.

  • Page 45: Tuner Function Check

    AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE 8. TUNER FUNCTION CHECK TUNER FUNCTION CHECK Check tuner Check tuner module voltage module(TU100) (Pin4: +3.3 V). operation. Check IC102 Pin21, 22, 23, 24, 25 data in/output. Check tuner module data. Refer to function check. 3-26...

  • Page 46: Cdp Electrical Troubleshooting Guide

    CDP ELECTRICAL TROUBLESHOOTIHG GUIDE 1. CD FUNCTION CD FUNCTION Can the Is Motor_open/close Is load +,- ok? disc insert? OK? (IC301 Pin10,11) Check IC301. Is Motor ok? Check loading motor. (about 12 Ω) Focus/ Check IC301 OPU driving (Focus Disc reading tracking/sled signal (Motor drive IC).

  • Page 47: Usb Function

    CDP ELECTRICAL TROUBLESHOOTIHG GUIDE 2. USB FUNCTION USB FUNCTION Plug-in usb device. Display “NO USB”. Check USB_5V. Check CN401. Check USB_D+/D- Display “READ”. Check usb jack (JK501). (R501,R502). Display “NO FILE”. Check IC801(Pin116, 117). Replace IC801. Check usb audio fi le in usb device (MP3, WMA fi...

  • Page 48: Waveforms

    WAVEFORMS 1. SDRAM IC802 Pin38 DATA IC802 Pin53 ADDRESS IC802 Pin35 IC803 Pin1 2. SERVO IC801 Pin63 CD-16M 3-29...
  • Page 49 IC302 Pin61 IC302 Pin62 IC302 Pin13 IC302 Pin63 3. AUDIO PATH IC801 Pin100 CD_BCK IC801 Pin102 CD_LRCK CD_DATA IC801 Pin101 3-30...
  • Page 50 DAC_MCK IC801 Pin86 DAC_BCK IC801 Pin87 DAC_LRCK IC801 Pin88 DAC_DATA IC801 Pin83 4. USB USB_5V IC801 Pin116 IC801 Pin117 3-31...
  • Page 51 MEMO 3-32...

  • Page 52: Wiring Diagram

    WIRING DIAGRAM (CDM-345) CN301 CN303 CN901 CN105 CN104 CN302 CN902 6PIN CN304 CN401 CN903 CN502 CN501 3-33 3-34...

  • Page 53: Block Diagrams

    BLOCK DIAGRAMS 1. OVERALL BLOCK DIAGRAM 16.93MHZ 12.288MHZ A,B,C,D,E,F DECK MECHANISM BU9543KV DAC-BCK/LRCK/MCLK RF+ SERVO DSP TAS5612 DAC-DATA P/UP PS9850 SLED ,F ,T SLDO SPDO SPINDLE AM5890S LOAD MOTOR EEPROM 9.8304MHZ OP/CL SPI-DO/DI/CLK/ CS RESET; MU ADC-RST I2S CLK MICOM MLC9800 OP/CL LI MIT ADC-DAT...

  • Page 54: Smps Block Diagram

    2. SMPS BLOCK DIAGRAM SMPS On/Off Snubber Block CN901 On/Off 5V LDO 5.6VA Main SMPS IC CN902/3 Regulation Block On/Off Block 3.7VA Noise Y-Cap Feedback Filter Photo coupler CD P.CTL Block (X-cap P.CTL Y-Cap Photo coupler On/Off Line Filter) Snubber Block PVDD SMPS IC...

  • Page 55: Circuit Diagrams

    MODIFIED OR ALTERED WITHOUT PERMISSION IMPLEMENTATION OF THE LATEST SAFETY AND during Play mode. FROM THE LG CORPORATION. ALL COMPONENTS PERFORMANCE IMPROVEMENT CHANGES INTO SHOULD BE REPLACED ONLY WITH TYPES IDENTICAL THE SET IS NOT DELAYED UNTIL THE NEW SERVICE TO THOSE IN THE ORIGINAL CIRCUIT.

  • Page 56: Micom & Ad Circuit Diagram

    2. MICOM & AD CIRCUIT DIAGRAM µ-COM & AD EBY61070801(#1) Rev 1.9 2010.11.09 3-41 3-42...

  • Page 57: Pwm & Amp Circuit Diagram

    3. PWM & AMP CIRCUIT DIAGRAM PWM & AMP EBY61070801(#2) Rev 1.9 2010.11.09 3-43 3-44...

  • Page 58: Cd Dsp & Servo Circuit Diagram

    4. CD DSP & SERVO CIRCUIT DIAGRAM 10 12 11 17 18 CD DSP & SERVO : WAVEFORM NUMBER EBY61070801(#3) Rev 1.9 2010.11.09 3-45 3-46...

  • Page 59: Front Circuit Diagram

    5. FRONT CIRCUIT DIAGRAM FRONT EBY61070901 Rev 2.2 2010.11.09 3-47 3-48...

  • Page 60: Usb Circuit Diagram

    6. USB CIRCUIT DIAGRAM EBY61071001 Rev 1.5 2010.11.09 3-49 3-50...

  • Page 61: Circuit Voltage Chart

    CIRCUIT VOLTAGE CHART 1. SMPS Board P.OFF(STANBY) P.ON (Unloaded) CD_PLAY (USB insert) Location Pin No. Specifi cation EE Mode (V) Margin Playback Mode (V) Margin Location Mode Voltage Current Voltage Current Voltage Current 43 (VDD_CORE) 1.08~1.32 1.24 0.08 1.24 0.08 (mA) (mA) (mA)
  • Page 62 MEMO EEMode Play back Rec voltage Location Value (uF) Spec Margin Margin Margin C118 1000uF 6.3V 3.5V 3.5V 2.8V 3.44V 3.44V 2.86V 3.39V 3.39V 2.91V C302 100uF 0.22V 0.22V 15.78V 3.31 3.31 12.69V 3.26 0.03 3.23V 12.77V C304 100uF 1.65V 1.65V 14.35V 1.64...

  • Page 63: Printed Circuit Board Diagrams

    PRINTED CIRCUIT BOARD DIAGRAMS 1. MAIN P.C.BOARD (TOP VIEW) Rev 2.2 3-55 3-56...
  • Page 64 MAIN P.C.BOARD (BOTTOM VIEW) EAX63554401 Rev 2.2 3-57 3-58...

  • Page 65: Smps P.c.board

    2. SMPS P.C.BOARD 3. FRONT P.C.BOARD NOTE) Warning Parts that are critical with respect to risk of fire or electrical shock. Rev 6.2 3-59 3-60...

  • Page 66: Usb P.c.board

    MEMO 4. USB P.C.BOARD 3-61 3-62...
  • Page 67 MEMO MEMO 3-63 3-64...

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