LG 24LF452B Service Manual

The LG 24LF452B is a 24-inch LED monitor featuring Full HD 1920x1080 resolution, IPS panel technology, HDMI and D-Sub inputs, built-in speakers, energy-saving features, and advanced display settings. This service manual provides comprehensive technical information for service technicians including disassembly procedures, troubleshooting guides, parts lists, and schematic diagrams.

1. Product Overview 2. Technical Specifications 3. Disassembly Procedures 4. Parts List 5. Circuit Diagrams 6. Troubleshooting Guide 7. Adjustment Procedures 8. Safety Precautions 9. Service Tools Required 10. Firmware Update 11. Contact Information

Product Overview

Main components: 24-inch IPS LED panel, main board, power supply board, control board, stand assembly, and connectivity ports.

Component	Description
Main Board	LVDS connector, HDMI input, VGA input, audio input
Power Supply Board	AC input, DC output to main board and LED backlight
Control Board	Power button, menu controls, LED indicators
Panel Assembly	24-inch IPS LCD with LED backlight
Stand Assembly	Tilt adjustment, VESA mount compatible
Input Ports	HDMI, D-Sub (VGA), Audio input
Built-in Speakers	2x 2W speakers

Technical Specifications

Screen Size: 24 inches IPS LED
Resolution: 1920 x 1080 Full HD
Brightness: 250 cd/m²
Contrast Ratio: 1000:1 (static)
Response Time: 5ms
Viewing Angle: 178°/178°
Inputs: HDMI, D-Sub (VGA)
Audio: 2W x 2 speakers, audio input
Power Consumption: 25W typical, <0.5W standby
Power Supply: Internal 100-240V AC, 50/60Hz
Dimensions: 565.9 x 417.9 x 218.5 mm (with stand)
Weight: 3.8 kg (with stand)

Disassembly Procedures

Follow these steps carefully to disassemble the monitor for service.

Remove stand: Lay monitor face down on soft surface, press stand release button and pull stand away.
Remove rear cover: Remove 4 screws from rear, carefully pry plastic clips around perimeter.
Disconnect cables: Note cable positions before disconnecting LVDS, power, and control cables.
Remove main board: Remove mounting screws and lift board from chassis.
Remove power board: Disconnect AC input and output cables, remove mounting screws.
Access panel: Remove metal shield and carefully handle LCD panel assembly.

WARNING! Disconnect power before disassembly. Handle LCD panel with care to avoid damage.

Parts List

Part Number	Description	Qty
EBT39595801	Main Board Assembly	1
EAX38596801	Power Supply Board	1
ECB39595801	Control Board	1
LC240WUN-SAB1	LCD Panel Assembly	1
6841-001597A	LED Backlight Unit	1
3831FR-0098A	Stand Assembly	1
3831FR-0099A	Rear Cover	1
3831FR-0100A	Front Bezel	1

Circuit Diagrams

Refer to separate schematic diagrams document for detailed circuit information:

Main Board Schematic - Page 15-20
Power Supply Schematic - Page 21-25
Control Board Schematic - Page 26-28
Backlight Driver Schematic - Page 29-30
Connector Pinouts - Page 31-32

Note: All voltages measured with respect to ground unless otherwise specified.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No power	Power board failure, fuse blown	Check AC input, test fuse F101, check DC output voltages
No display	Main board, LVDS cable, panel	Check LVDS connection, test main board voltages, verify panel operation
Backlight failure	LED strips, backlight driver	Test LED strings, check backlight driver IC, replace LED strips if needed
No sound	Audio IC, speakers, cables	Check audio input, test speaker continuity, replace audio IC U701
Image distortion	Main board, T-con board	Check T-con voltages, replace main board if pattern issues persist
Buttons not working	Control board, flex cable	Test button continuity, check flex cable connection, replace control board

Adjustment Procedures

Service menu access: Press and hold MENU button on monitor for 5 seconds while powered on.

White Balance Adjustment: Use color analyzer to adjust R-G-B gain and offset
Backlight Adjustment: Set appropriate brightness level for power saving
Geometry Adjustment: Adjust horizontal/vertical position and size
Factory Reset: Reset all settings to factory defaults
Panel Information: Check panel type and usage hours

CAUTION! Service menu adjustments should only be performed by qualified technicians.

Safety Precautions

Always follow these safety guidelines during service:

Disconnect AC power before servicing
Use anti-static wrist strap when handling boards
Handle LCD panel with care to avoid breakage
Check capacitors for proper discharge before touching
Use insulated tools when working with live circuits
Replace safety-critical components with exact specifications

WARNING! High voltage present in power supply and backlight circuits.

Service Tools Required

Digital Multimeter
ESD-safe screwdriver set
Anti-static wrist strap
LCD opening tools
Oscilloscope (for advanced troubleshooting)
LED backlight tester
Color analyzer (for white balance adjustment)

Firmware Update

Firmware update procedure via service port:

Download latest firmware from LG service website
Connect USB-to-TTL converter to service port (J800)
Set baud rate to 115200, 8N1
Power on monitor while holding factory reset combination
Follow on-screen prompts to complete update
Do not interrupt power during update process

Note: Firmware updates may erase user settings and service adjustments.

Contact Information

For technical support and parts ordering:

LG Electronics Service Division: 1-800-243-0000
LG Service Website: www.lg.com/us/support
Parts Ordering: [email protected]
Technical Documentation: [email protected]
Service Centers: Refer to LG website for authorized service locations

Service Hours: Monday-Friday 8:00 AM - 9:00 PM EST