Disassembly Guide
Required Tools:
- Torx screwdriver set (T10-T25)
- Phillips screwdrivers (#1, #2)
- Flathead screwdriver
- Nut drivers (7mm, 8mm, 10mm)
- Multimeter
- Pliers set
Step-by-Step Disassembly
- Safety First: Disconnect power supply and water connections before beginning any service procedures.
- Top Panel Removal: Remove rear screws and slide top panel backward to release from front panel clips.
- Control Panel Access: Detach control panel connectors and remove mounting screws to access electronic components.
- Front Panel Removal: Remove door seal clamp, detach door lock mechanism, and unscrew front panel mounting points.
- Drum Assembly Access: Remove counterweight, drive belt (if applicable), and motor mounting bolts.
- Pump and Valve Service: Access drain pump and water inlet valves by removing lower front panel and service cover.
- Reassembly: Reverse disassembly procedure, ensuring all connectors are properly seated and fasteners are tightened to specification.
Component Specifications
| Direct Drive Motor | Permanent Magnet Synchronous Motor |
| Motor Power Rating | 400W nominal, 800W peak |
| Control Board | Main PCB with inverter control |
| Drain Pump | 25W centrifugal pump |
| Water Inlet Valves | Solenoid type, 24V DC operation |
| Door Lock | Electronic interlock with thermal cutout |
| Temperature Sensor | NTC thermistor, 10kΩ at 25°C |
| Pressure Switch | Diaphragm type, 3-level detection |
| Tachometer Sensor | Hall effect sensor, 12 pulses/revolution |
| Heater Element | 1800W, stainless steel sheath |
Replacement Parts Information
- Motor Assembly: Part #MCL73883701
- Main Control Board: Part #EBR77629403
- Drain Pump: Part #4681EA2001T
- Door Lock: Part #AH3533165
- Drum Spider: Part #4723FR1006B
For genuine LG replacement parts, contact LG Parts Distribution at 1-800-243-0000 or visit LGPart.com
Diagnostic Procedures
| Error Code | Description | Diagnostic Procedure |
|---|---|---|
| PE | Pressure sensor error | Check pressure hose for blockage, test pressure sensor continuity |
| IE | Water supply error | Verify water pressure, test inlet valve operation, check filter screens |
| OE | Drain system error | Inspect drain hose, test pump operation, check for obstructions |
| FE | Water overflow detected | Check pressure system, inspect tub for proper drainage |
| LE | Motor position error | Test hall sensor, check motor connections, verify rotor position |
| TE | Temperature sensor error | Measure sensor resistance, check wiring harness |
Advanced Diagnostics
Service Test Mode
Access service mode by pressing specific button combinations to run component tests and view real-time sensor data for accurate diagnosis.
Motor Diagnostics
Test motor windings for proper resistance values and check hall sensor output signals to identify motor assembly issues.
Control Board Testing
Verify proper voltage outputs from power supply section and test communication between main board and display board.
Repair Instructions
Motor Replacement
Complete procedure for Direct Drive motor replacement including rotor alignment, bolt torque specifications, and electrical connection verification.
Drum Bearing Service
Step-by-step guide for replacing drum bearings and seals, including special tools required and proper lubrication procedures.
Control Board Repair
Troubleshooting common control board failures and replacement procedures for main PCB and power supply components.
Door Seal Replacement
Procedure for replacing door boot seal, including proper alignment and tensioning to prevent leaks and ensure door closure.
Heater Element Service
Testing and replacement instructions for heating elements, including thermal cutout reset and temperature calibration.
Pump Maintenance
Cleaning and replacement procedures for drain pump assembly, including impeller inspection and foreign object removal.
Torque Specifications
| Motor Mounting Bolts | 45-50 Nm |
| Counterweight Bolts | 25-30 Nm |
| Drum Spider Nut | 120-140 Nm |
| Suspension Rod Nuts | 15-20 Nm |
Service Downloads
Service Manuals
WM3900H Series
Service Manual v2.1
WM4000H Series
Service Manual v3.0
WM4200H Series
Technical Bulletin Update
WM9000 Series
Advanced Service Guide
Technical Resources
Wiring Diagrams
Complete schematic set
Parts Catalog
Exploded views and parts list
Firmware Updates
Latest software versions
Technical Bulletins
Service updates and recalls