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LG 28LB474A Service Manual
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LG 28LB474A Service Manual

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LED TV
SERVICE MANUAL
CHASSIS : LB45N
MODEL : 28LB474A
CAUTION
BEFORE SERVICING THE CHASSIS,
READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL68122404 (1405-REV00)
North/Latin America
Europe/Africa
Asia/Oceania
28LB474A-TF
Internal Use Only
http://aic.lgservice.com
http://eic.lgservice.com
http://biz.lgservice.com
Printed in Korea

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Summary of Contents for LG 28LB474A

  • Page 1 Internal Use Only North/Latin America http://aic.lgservice.com Europe/Africa http://eic.lgservice.com Asia/Oceania http://biz.lgservice.com LED TV SERVICE MANUAL CHASSIS : LB45N MODEL : 28LB474A 28LB474A-TF CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. P/NO : MFL68122404 (1405-REV00) Printed in Korea...

  • Page 2: Table Of Contents

    ADJUSTMENT INSTRUCTION ..............9 TROUBLE SHOOTING GUIDE ............... 13 BLOCK DIAGRAM .................. 24 EXPLODED VIEW .................. 25 SCHEMATIC CIRCUIT DIAGRAM .............. - 2 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 3: Safety Precautions

    An other abnormality exists that must be corrected before the receiver is returned to the customer. - 3 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 4: Servicing Precautions

    - 4 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 5 1. Clip each fuse or resistor lead at top of the circuit board hollow stake. 2. Securely crimp the leads of replacement component around notch at stake top. - 5 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 6: Specification

    20/22/28/29LB4**A: 1EA 32/42LB5**A: 2EA 11. Audio Input (1EA) AV&Component &PC * PC Audio input are only supported the RGB-PC models. - 6 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 7 Min Vertical Freq - 58 Hz/ Max Vertical Freq - 63 Hz Min Horiz. Freq - 28 kHz/ Max Horiz. Freq - 68 kHz Pixel Clock - 150 MHz - 7 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 8 HDTV 1080P 1920*1080 33.75 30.00 74.25 HDTV 1080P 1920*1080 26.97 23.97 74.25 HDTV 1080P 1920*1080 33.716 29.976 74.25 HDTV 1080P - 8 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 9: Adjustment Instruction

    HDMI1 Block 0 check sum (Hex) Block 1 <Small RGB> LB45S/R/N- 22/28/29LB4xxA RGB C/S data check sum(Hex) Block 0 - 9 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 10 - Fix the one of R/G/B gain to 192(default data) and decrease the others. 3) Adjustment mode : Two modes - Medium / Warm - 10 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 11 GND. target - Hi-pot Test = POWER CORD GND and LIVE & NEUTRAL. (4) LEAKAGE CURRENT: At 0.5 mArms - 11 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 12 6.White Balance, you can select one of 2 Test-pattern: ON, OFF. Default is inner(ON). By selecting OFF, you can adjust using RF signal in 216 Gray pattern. - 12 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 13: Trouble Shooting Guide

    Is there any waver at 11pin of P120, change IR board when use remote control? Or check Line short or open of P120 Insert F/W X501 - 13 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 14 If is under 4.5V at L110, Check open and short Of line between L110 and P101. Insert the F/W back or REPLACE LCD MODULE - 14 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 15 Or Check LVDS cable have damage. Another is change IC501. Change module WAVEFORMS 6,7,12,13,15,16,18,19 Pin of 1201 9,10Pin of P101 (Data Line) (Clock line) - 15 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 16 44 pin of IC501? IC501 or TU401 Change Main PCBA WAVEFORMS 43,44pin of IC501 4Pin of TU401 (SDA) 3Pin of TU401 (SCL) - 16 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 17 Check Line between JK101 and IC501 is open or short, Another is Is waveform at R505 change AV cable Change IC501 WAVEFORMS R505 (CVBS) - 17 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 18 Is waveform at R501 is open or short, Another is R502, R504 Change RGB cable Change IC501 WAVEFORMS R601(B) R604(R) R502(G) - 18 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 19 Check Line between JK203 and IC501 Is waveform at 1,3,4,6,7,9pin is open or short, Another is Of JK203? Change HDMI cable Change IC501 - 19 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 20 And then check resistance Is there any waveform P301? of speaker is under 4ohm. Another is change IC301 Change speaker and wire - 20 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 21 44 pin of IC501? IC501 or TU401 Change Main PCBA WAVEFORMS 43,44pin of IC501 4Pin of TU401 (SDA) 3Pin of TU401 (SCL) - 21 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 22 Check Line between JK101 and IC501 is open or short, Another is Is waveform at C520,C521 change AV cable Change IC501 WAVEFORMS C520,C521(audio in) - 22 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 23 Check Line between JK203 and IC501 Is waveform at 1,3,4,6,7,9pin is open or short, Another is Of JK203? Change HDMI cable Change IC501 - 23 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 24: Block Diagram

    BLOCK DIAGRAM - 24 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

  • Page 25: Exploded View

    X-RADIATION, Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer. - 25 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 26 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. INPUT1/LVDS INPUT1/LVDS Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 27 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR INPUT2 THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. INPUT2 Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 28 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR AUDIO THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. AUDIO Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 29 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR TUNER & IR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. TUNER Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 30 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MAIN SOC MAIN SOC Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 31 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR LED_Driver THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. LED DRIVER Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 32 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. POWER POWER Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
  • Page 33 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR DC BOOST UP THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. BOOST-UP Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...

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