LG WT7900H A Series Service Manual
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LG WT7900H A Series Service Manual

LG WT7900H A Series Service Manual

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WASHING MACHINE
SERVICE MANUAL
CAUTION
READ THIS MANUAL CAREFULLY TO DIAGNOSE
PROBLEMS CORRECTLY BEFORE SERVICING THE UNIT.
MODEL : WT7900H*A
Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means), publication, modification, copying or
transmission of this Service Manual is STRICTLY PROHIBITED unless you have obtained the prior written consent of the LG Electronics entity
from which you received this Service Manual. The material covered by this prohibition includes, without limitation, any text, graphics or logos in
this Service Manual.
Copyright © 2018~2019 LG Electronics Inc. All rights reserved. Only training and service purposes.
CONFIDENTIAL
Copyright © 2016 - 2017 LG Electronics Inc. All rights
reserved. Only training and service purposes.

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Summary of Contents for LG WT7900H A Series

  • Page 1 Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means), publication, modification, copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you have obtained the prior written consent of the LG Electronics entity from which you received this Service Manual. The material covered by this prohibition includes, without limitation, any text, graphics or logos in this Service Manual.

  • Page 2: Table Of Contents

    4-2. Wiring Diagram ....... 27 4-3. Test Running Without Water ... 28 4-4. Troubleshooting By Common Washing Problems ......29 4-5. Troubleshooting Summary ....30 Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 3: Specifications

    1 – 19 Hr Lid Interlock Switch Magnet Sensor Control Lock Softener Dispenser Detergent Dispenser Bleach Inlet Auto Power Off Smart Rinse™with Jet Spray Heater Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 4: Installation Instructions

    Wooden floors may need reinforcing to prevent the normal vibration which occurs with an unbalanced load. Do not install the washer on an inclined floor. Improper installation of the washer may cause noise and malfunctioning. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 5 Where the washer is exposed to direct sunlight. Near a heater or heating appliance. Where the washer is exposed to freezing temperatures. In damp environments such as bathrooms or harmful environments. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 6: Connecting Water Supply Hose

    Cold water inlet the washing machine, and then lock it by turning the hose connecting part. connector. new hoses. The old hoses should not be reused. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 7: Connect The Drain Hose

    Failure to do so can result in damage to the machine. or serious injury. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 8: Operating Instructions

    BASE LEVELLING LEGS Use to level the washing machine for correct balance spin operation. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 9: Before Starting To Wash

    Fasten zippers, hooks, and strings to make sure that these items don't snag on other clothes. ※ The nylon washing bag is not supplied by Kenmore. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 10: Water Temperature

    If iron is present in the water, the clothes may become an all-over yellow or they may be stained with brown or orange spots or streaks. Iron is not always visible. Installation of water softener or an iron filter may be necessary for severe cases. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 11: Using Detergent

    Using too much bleach can damage fabrecs. Main Wash Main Wash Powder Detergent Liquid Detergent Compartment Compartment Liquid Fabric Softener Compartment Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 12: Using The Dispenser Drawer

    NOTE: It is normal for a small amount of water to remain in the dispenser compartments at the end of the cycle. NOTE: Do not use powdered or liquid bleach in the dispenser drawer. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 13: Adding Detergent

    Overfilling can cause early dispensing of presoak additives, which could result in damaged clothes. NOTE : Do not pour additives directly on the wash load. It may stain the clothes. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 14: Special Guide For Stain Removal

    Never use highly flammable solvents, such as gasoline, inside the home. Vapors can explode on contact with flames or sparks. For successful stain removal: chart below. powdered detergent and water. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 15: Stain Removal

    Pretreat with prewash stain remover or nonflammable dry cleaning fluid. Rub detergent into dampened area. Wash using bleach safe for fabric. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 16: Function Of Each Button

    ▶ ▶ ▶ ▶ ▶ DELAY WASH (Selection) WASH / TEMP. BUTTON ▶ ▶ ▶ ▶ ▶ ▶ ▶ ▶ ▶ ▶ ▶ Note Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 17 EXTRA RINSE START/ PAUSE BUTTON BUTTON SIGNAL CONTROL LOCK SPIN SPEED SOIL LEVEL BUTTON FUNCTION ▶ ▶ ▶ Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 18: Washing Programs

    Cold Extra Water Turbo Cycle Wash Temp. Soak Steam Speed Level Care Wash Rinse Plus Wash Normal Heavy Duty Bedding Deep Wash Bright Whites™ Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 19 Cold Extra Water Turbo Cycle Wash Temp. Soak Steam Speed Level Care Wash Rinse Plus Wash Sanitary Allergiene Pre Wash+ Normal Delicates Perm. Press Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 20 Cold Extra Water Turbo Cycle Wash Temp. Soak Steam Speed Level Care Wash Rinse Plus Wash Towels Speed Wash Waterproof Downloaded Default: Small Load Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 21: Care And Maintenance

    We do not recommend the use of dye strippers in your washer. Do not use your washer lid as a work surface. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 22: Service Information

    When assembling the PCB and Front panel by pushing the PCB to the upper and check the Segment seated. After assembly check the light spread. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 23: Pressure Switch

    Dispenser Housing & Inlet Valve ① Remove the hoses and Lead Wire from the input valve. ② Disassemble the Inlet valve and the dispenser housing. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 24: Disassembly Of Top Cover

    ⑥ Remove 1 Screw, Cover, and Safety from the Cabinet. ⑦ According to the environment, place the Top cover on the floor at the side or back of the washer. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 25 5) Assemble the service tool (38 mm wrench) 6) Remove the hub attachment nut. (38 mm) Hit the bar using the hammer. Disconnect hub nut and disassemble the inner tub. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 26 (The torque should be 250 kgf/cm or 88 foot- pounds.) Remove the rotor by pulling it straight off the splined shaft. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 27 When assembling the rotor, hold the outer parts and to axial direction. Be careful your fingers are not stuck between rotor and stator by magnetic force. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 28 Loosen the nut at the middle of the heater to relieve the ② tension on the clamp. Then pull it out of the case. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 29: Wiring Diagram

    4-2. WIRING DIAGRAM Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 30: Test Running Without Water

    Agitate (tub) check and Door Lock check t8 and RPM 12 time Spin check t9 and RPM 13 time Unlocks the door None Turns off all LED Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 31: Troubleshooting By Common Washing Problems

    · Incorrect use of chlorine bleach. or snags · Unfastened zippers, hooks, buckles · Ribs, tears and broken threads · Overloading the washer · Degradation of fabric Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 32: Troubleshooting Summary

    4-5. TROUBLESHOOTING SUMMARY Test Points Result Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 33: Pcb Picture

    4-6. PCB Picture Main PCB Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 34: Troubleshooting With Error Code

    If no beep, change the noise filter, including -. Check the Short between top switch the fuse. Heatsink and GY pin by Tester 2. If beep sound, replace the PCBA. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 35: Drain Error

    Check the AIR When you enter the SVC CHAMBER, the Mode, is the water level tube (clogged), frequency below 26.0 kHz? and press switch Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 36 - Part of wire - After pull out the GY3 connector, check the terminal of the connector in wire. Replace the MAIN PCB ASSEMBLY. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 37: Unbalance Error

    If the inlet valve when the power is not work continuously applied? when the power is applied, Replace the MAIN PCB ASSEMBLY Replace the INLET VALVE ASSEMBLY Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 38: Pressure Sensor Error

    (pin 1~ pin 3) Fix the air Is the AIR CHAMBER and the chamber and tube clogged? remove the foreign material Replace the MAIN PCB assembly Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 39: Other Troubleshooting

    Display PCB Reconnect or Is the connector connected to repair the PCB/Noise filter disconnected connector or disassembled? Connecting connector MAIN PCB~ Display PCB Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 40 ASSEMBLY LED light while touch the disassembled? LCD) Connecting connector Main PCB~ Display PCB Is the button of panel stuck? Repair the button Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 41: Component Testing Information

    5-1. FILTER ASSEMBLY (LINE FILTER) Circuit in the MAIN PCB / Wiring Diagram Wiring diagram Test points Result Test Points Result WH to BL YL to RD Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 42: Door Lock Switch Assembly

    – maximum of 3 times of the authorizing period - Upon the fourth authorization of the impulse, the position of CAM goes back to the door-close position. Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 43 Test points Test Points Result (1)To (2) Result (1)-Black / (2)-Brown (4) To (5) 9 ~ 11 AT (4)-White / (5)-Green Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 44: Stator Assembly

    WINDINGS Test points (Windings) (1) (3) Test Points Result (1) to (2) Result (2) to (3) (Windings) (3) to (1) Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 45: Pump Motor Assembly

    * Each circuits of loads in wiring diagram are all same. Test Points Result (1) to (2) (2) to (3) (3) to (1) Test points Result Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 46: Inlet Valve Assembly

    After unplugging the connector of the defective valve, check the resistance. Test Test points (1)-(2) Points Result Result Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

  • Page 47: Exploded View

    6. EXPLODED VIEW BODY-A BODY-B Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 48 A011 A062 A061 A063 A240 A056 A064 A203 A202 A201 A050 A051 A200 A148 A180 A020 A183 A152 A186 A154 A153 A147 A151 A150 A241 A410 A105 A230 A100 A190 A125 A030 A040 A157 A140...
  • Page 49 F032 F011 F005 F070 F005 F005 F000 F100 F090 F040 F020 F086 F080 F027 F023 S100...
  • Page 50 K000 K012 K021 K020 K030 K040 K050 K33A K100 K060 K104 K250 K064 K350 K080 K170 K140 K345 K341 K200 K290 K230 K210 K305 K201 K400 K420 K410 K300...

  • Page 51: Wiring Diagram

    7. WIRING DIAGRAM Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.
  • Page 52 Jan. 2019 PRINTED IN KOREA MFL69647011 Copyright © 2016 - 2017 LG Electronics Inc. All rights reserved. Only training and service purposes.

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