LG 32LM3400 Service Manual

The LG 32LM3400 is a 32-inch LED TV featuring Full HD resolution, built-in digital tuner, multiple HDMI inputs, USB connectivity, Energy Star certification, webOS smart platform, Magic Remote compatibility, built-in Wi-Fi, Clear Voice Pro sound enhancement, and various picture modes. Below are key sections for technical specifications, disassembly procedures, troubleshooting, circuit diagrams, and repair guidelines.

1. Technical Specifications 2. Safety Precautions 3. Disassembly Procedures 4. Main Board Replacement 5. Power Supply Board 6. LCD Panel Replacement 7. Troubleshooting Flowcharts 8. Circuit Diagrams 9. Software Update Procedures 10. Parts List 11. Test Points & Voltages

Technical Specifications

Key components: LED panel, main board, power supply board, T-CON board, backlight system.

Specification	Details
Model	32LM3400
Screen Size	32 inches LED
Resolution	1366 x 768 (HD Ready)
Tuner	ATSC/NTSC/Clear QAM
Inputs	3x HDMI, 2x USB, Component, Composite, RF
Smart Platform	webOS 3.0
Power Consumption	35W typical, 0.3W standby
Power Supply	100-240V AC, 50/60Hz
Backlight Type	LED Edge Lit
Weight	4.8 kg (without stand)

Safety Precautions

Before servicing, ensure proper safety measures are followed.

Disconnect power: Always unplug from AC outlet before disassembly.
ESD protection: Use anti-static wrist strap when handling boards.
Capacitor discharge: Wait 5 minutes after power disconnect for PSU capacitors to discharge.
LCD handling: Avoid pressure on screen; handle by edges only.

WARNING! High voltages present in power supply section. Only qualified technicians should perform repairs.

Disassembly Procedures

Step-by-step guide for accessing internal components.

Remove stand: Lay TV face down on soft surface, remove screws securing stand.
Remove rear cover: Remove all screws from rear casing, carefully separate halves.
Access main board: Remove metal shield covering main board.
Disconnect cables: Note cable positions before disconnecting.
Remove power board: Disconnect AC input and output cables.

CAUTION! LCD panel is fragile; avoid bending or applying pressure.

Main Board Replacement

Part Number: EAX65443301
Tools Required: Phillips screwdriver, anti-static wrist strap
Procedure: Remove rear cover, disconnect all cables, remove mounting screws, replace board
Testing: Verify all functions after replacement
Software: May require firmware update after board replacement

Power Supply Board

Power supply board specifications and troubleshooting.

Output	Voltage	Current	Purpose
+12V	12V ±5%	3.0A max	Main board power
+24V	24V ±5%	1.5A max	Backlight inverter
+5V STBY	5V ±5%	1.0A max	Standby power
+3.3V	3.3V ±5%	0.5A max	Standby circuitry

Common Issues: No power, blinking standby LED, backlight failure

LCD Panel Replacement

Panel replacement requires careful handling and proper tools.

Remove bezel: Carefully pry plastic bezel from front frame.
Remove diffuser sheets: Note orientation for reassembly.
Disconnect LVDS cables: From T-CON board to panel.
Remove panel: Lift straight up from frame.
Install new panel: Reverse procedure with new panel.

WARNING! Do not touch panel circuits; static discharge can damage panel.

Troubleshooting Flowcharts

Systematic approach to common problems.

Symptom	First Check	Next Steps
No power	AC input, fuse	Check standby voltage, PSU components
No backlight	Backlight voltage	Check inverter, LED strips, dimming circuit
No picture/sound	Main board power	Check main board voltages, firmware
Distorted picture	T-CON board	Check LVDS cable, T-CON voltages
No sound	Audio settings	Check audio IC, speakers, connections

Circuit Diagrams

Reference diagrams for main board, power supply, and T-CON board.

Main Board: Block diagram showing processor, memory, input/output sections
Power Supply: Schematic with component values and test points
T-CON Board: Timing controller circuit and gamma reference voltages
Backlight: LED driver circuit and current regulation

Note: Diagrams are for reference only; component-level repair requires advanced skills.

Software Update Procedures

Firmware update methods and troubleshooting.

USB update: Download firmware from LG service site, extract to USB root directory.
Enter service menu: Hold MENU button on both TV and remote for 5 seconds.
Select update: Navigate to software update section.
Start update: Do not power off during update process.
Verification: TV will restart automatically after update.

CAUTION! Incorrect firmware can brick the TV; use exact model-specific firmware.

Parts List

Common replacement parts with part numbers.

Component	Part Number	Description
Main Board	EAX65443301	Complete main logic board
Power Supply	EAX65443302	AC/DC power supply board
LCD Panel	LC320EXN-SEA1	32-inch LED panel assembly
T-CON Board	EAX65443303	Timing control board
Remote Control	AKB73975608	Magic Remote replacement
Stand	AKB73975609	Table stand assembly

Test Points & Voltages

Critical test points for troubleshooting.

Test Point	Normal Voltage	Location
PS_ON	3.3V (standby), 0V (on)	Main board connector
BL_ON	3.3V (backlight on)	Main board to PSU
+12V_Main	12V ±5%	Power supply output
+5V_STBY	5V ±5%	Standby power rail
VGH	+18V to +25V	T-CON board
VGL	-5V to -7V	T-CON board

Reset Procedures: Service menu > Reset to Factory Defaults

Service Support: LG Service Center: 1-800-243-0000; www.lg.com/us/support