LG 37LC2D-UD Service Manual

The LG 37LC2D-UD is a 37-inch LCD television featuring 1366x768 resolution, built-in digital/analog tuner, multiple input interfaces including HDMI, component video, composite video, PC input, and USB connectivity. This service manual provides comprehensive technical information for service technicians including disassembly instructions, circuit diagrams, troubleshooting procedures, and replacement part information.

1. Safety Precautions 2. Product Specifications 3. Disassembly Instructions 4. Circuit Diagrams 5. Block Diagrams 6. PCB Layouts 7. Troubleshooting Guide 8. Adjustment Procedures 9. Replacement Parts List 10. Exploded Views 11. Service Mode Access

Safety Precautions

Important safety information for service technicians working on the LG 37LC2D-UD LCD television.

Warning	Description
High Voltage	Power supply contains lethal voltages even when unplugged
Capacitor Discharge	Allow 5 minutes for power supply capacitors to discharge
LCD Panel Handling	Handle LCD panel carefully to avoid cracking or damage
ESD Protection	Use anti-static wrist strap when handling circuit boards
Backlight Inverter	Inverter produces high voltage AC for CCFL lamps
Power Board	Isolate power board during testing using isolation transformer

Product Specifications

Model: 37LC2D-UD
Screen Size: 37 inches LCD
Resolution: 1366 x 768 pixels
Brightness: 500 cd/m²
Contrast Ratio: 1600:1
Response Time: 8ms
Viewing Angle: 178°/178°
Tuner: ATSC/NTSC/QAM
Inputs: HDMI x2, Component x1, Composite x2, PC Input, USB
Power Consumption: 150W typical

Disassembly Instructions

Step-by-step procedure for disassembling the LG 37LC2D-UD television.

Remove stand: Lay TV face down on soft surface, remove screws securing stand.
Remove rear cover: Remove all screws from rear cabinet, carefully separate rear cover.
Disconnect cables: Note cable positions before disconnecting from main board.
Remove main board: Remove screws securing main PCB, lift board carefully.
Remove power supply: Disconnect all cables, remove mounting screws.
Access LCD panel: Remove metal shield to access LCD panel and backlight assembly.

WARNING! Handle LCD panel with extreme care to avoid permanent damage.

Circuit Diagrams

Complete circuit schematics for all major sections of the television.

Main Board Schematic: EAX32053801
Power Supply Schematic: EAX32053802
Inverter Board Schematic: EAX32053803
T-CON Board Schematic: EAX32053804
Key & Remote Control Schematic: EAX32053805

Refer to separate schematic diagrams document for detailed circuit analysis.

Block Diagrams

System block diagrams showing signal flow and interconnections.

Diagram	Description
System Block Diagram	Overall system architecture and signal flow
Video Processing	Video signal processing from input to LCD panel
Audio System	Audio processing and amplification path
Power Distribution	Power supply distribution to all subsystems
Control System	Microprocessor control and interface circuits

PCB Layouts

Printed circuit board layouts for all major boards.

Main Board Layout: Component placement and trace routing
Power Supply Layout: High voltage section isolation
Inverter Board Layout: Backlight driver circuit layout
T-CON Board Layout: Timing controller board layout
Input Board Layout: Input connector board layout

Use layouts for component identification and trace continuity testing.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No Power	Power supply failure	Check fuse F101, test standby voltage, replace power board
No Backlight	Inverter failure	Check inverter output, replace CCFL lamps or inverter board
No Video	Main board/T-CON failure	Check LVDS output, test T-CON board voltages
No Audio	Audio circuit failure	Test audio IC U601, check speaker connections
Color Problems	T-CON or panel failure	Check gamma voltages, replace T-CON board
Remote Not Working	IR sensor failure	Test IR sensor IC701, check remote control battery

Adjustment Procedures

Factory adjustment procedures for proper television operation.

White Balance Adjustment: Enter service mode, adjust RGB cuts and drives
Geometry Adjustment: Adjust horizontal/vertical position and size
Color Temperature: Set color temperature to 6500K standard
Backlight Adjustment: Set backlight level to factory specification
Audio Level: Adjust audio output levels for each input

All adjustments require service remote control or service mode access.

Replacement Parts List

Original LG replacement parts for the 37LC2D-UD model.

Part Number	Description	Qty
EAX32053801	Main Board Assembly	1
EAX32053802	Power Supply Board	1
EAX32053803	Inverter Board	1
EAX32053804	T-CON Board	1
6871QDH018A	LCD Panel 37"	1
LGAC34934001	Remote Control	1

Exploded Views

Exploded view diagrams showing all components and their relationships.

Cabinet Assembly: Front bezel, rear cover, and stand assembly
Chassis Assembly: Internal frame and mounting points
LCD Module: LCD panel, backlight, and optical films
Board Assembly: All PCB locations and mounting
Input Panel: Input connector board and wiring

Use exploded views for proper reassembly and part identification.

Service Mode Access

Procedures for accessing and navigating the service menu.

Access Method: Press MENU button on TV, then press 1-1-2-5 on remote
Service Menu: Contains adjustment and test patterns
Factory Reset: Option in service menu to restore factory settings
Burn-in Prevention: Orbiter and pixel shifting options
Panel Information: Display panel usage hours and model information

WARNING! Incorrect service menu settings can cause permanent damage.