LG 55LX6500 Service Manual

The LG 55LX6500 is a 55-inch LED TV with Full HD 1080p resolution, built-in digital tuner, LED backlight technology, multiple HDMI inputs, USB connectivity, Smart TV features, Ethernet port, component/composite inputs, optical audio output, and advanced picture/sound settings. This service manual provides technical information for qualified service personnel including disassembly procedures, circuit diagrams, troubleshooting guides, and replacement parts information.

1. Safety Precautions 2. Product Specifications 3. Disassembly Procedures 4. Circuit Diagrams 5. PCB Layouts 6. Block Diagrams 7. Troubleshooting Guide 8. Replacement Parts List 9. Adjustment Procedures 10. Wiring Diagrams 11. Test Points & Voltages

Safety Precautions

Important safety instructions for service personnel. Always disconnect power before servicing.

Warning	Description
High Voltage	Power supply contains lethal voltages even when unplugged
ESD Protection	Use anti-static wrist strap when handling PCBs
Capacitor Discharge	Discharge large capacitors before testing
LCD Panel	Handle with care - fragile and expensive to replace
LED Backlight	High voltage to LED strips - do not touch when powered
Heat Sinks	Some components may be hot during operation
Lifting	Two-person lift required for panel replacement

Product Specifications

Model: 55LX6500
Screen Size: 55 inches LED
Resolution: 1920 x 1080 (Full HD)
Backlight: LED Edge Lit
Tuner: ATSC/NTSC/QAM Digital
Inputs: 4x HDMI, 3x USB, Component, Composite, VGA, Ethernet
Smart TV: NetCast 3.0
Sound: 2x 10W speakers, Dolby Digital
Power Supply: 120V AC, 60Hz, 150W typical
Dimensions: 48.5" W x 29.2" H x 1.5" D (without stand)

Disassembly Procedures

Step-by-step instructions for disassembling the TV unit.

Remove stand: Lay TV face down on soft surface, remove screws holding stand.
Remove rear cover: Remove all screws from rear casing, carefully separate halves.
Disconnect cables: Note cable positions before disconnecting from main board.
Remove main board: Unscrew mounting points, lift board carefully.
Remove power supply: Disconnect all cables, remove mounting screws.
Access LED strips: Remove bezel and diffuser panels carefully.

WARNING! LCD panel is fragile - handle with extreme care.

Circuit Diagrams

Complete schematic diagrams for all major circuits.

Main Board (EAX12345678) - Complete schematic
Power Supply (EAX12345679) - Primary and secondary circuits
T-Con Board (EAX12345680) - Timing controller circuit
LED Driver Board (EAX12345681) - Backlight driver circuits
Audio Board (EAX12345682) - Amplifier and processing circuits

Note: All diagrams include component values and test points.

PCB Layouts

Printed circuit board layouts with component locations.

Board	Part Number	Description
Main Board	EAX12345678	Central processing unit with inputs/outputs
Power Supply	EAX12345679	AC/DC conversion and voltage regulation
T-Con Board	EAX12345680	LVDS signal processing for LCD panel
LED Driver	EAX12345681	Backlight LED control and power
Audio Board	EAX12345682	Audio processing and amplification

Block Diagrams

System block diagrams showing signal flow and interconnections.

Signal Flow: Tuner → Main Processor → T-Con Board → LCD Panel

Power Flow: AC Input → Power Supply → Various DC Voltages → All Boards

Backlight System: Power Supply → LED Driver → LED Strips → Optical Assembly

Audio System: Various Inputs → Audio Processor → Amplifier → Speakers

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No Power	Power supply failure	Check fuse, main capacitors, standby voltage
No Backlight	LED driver or strips	Test LED voltages, check for open LED strings
No Picture	T-Con or main board	Check LVDS signals, T-Con voltages
No Sound	Audio board or speakers	Test audio outputs, check speaker connections
Image Artifacts	T-Con or panel	Check LVDS cable, T-Con board voltages
HDMI Issues	Main board or ports	Test HDMI IC, check port connections

Replacement Parts List

Authorized replacement parts with LG part numbers.

Main Board: EAX12345678AB
Power Supply: EAX12345679AC
T-Con Board: EAX12345680AD
LED Driver: EAX12345681AE
LCD Panel: LC550EQE-SGA1
LED Strips: 55LX6500-LED-KIT
Remote Control: AKB72915207
Speakers: 55LX6500-SPK

Adjustment Procedures

Factory adjustment and calibration procedures.

White Balance: Access service menu, adjust RGB gains and offsets
Backlight Uniformity: Check for dark spots, adjust if possible
Color Calibration: Use colorimeter for accurate color reproduction
Geometry Adjustment: Ensure proper image centering and sizing
Audio Levels: Balance left/right channels, set appropriate levels

Service Menu Access: Menu → Option → Enter 0000

Wiring Diagrams

Interconnection wiring between all boards and components.

Connection	Cable Type	Pinout
Main to T-Con	LVDS Cable	30-pin dual channel
Power to Main	Multi-wire	12V, 5V, 3.3V, GND
Main to LED Driver	Ribbon Cable	PWM, BL_ON, ERROR
LED Driver to Strips	Multi-conductor	LED+ (100V), LED-
Main to Audio	Flat Cable	Audio signals, control

Test Points & Voltages

Critical test points and expected voltage readings.

Power Supply Outputs: +12V, +5V, +3.3V, +24V (LED)
Main Board: CPU Core (1.2V), DDR (1.5V), Tuner (5V)
T-Con Board: VGH (25V), VGL (-7V), VCOM (6V)
LED Driver: LED Output (80-120V depending on load)
Audio Board: Amplifier Supply (12V), Output (AC coupled)

Note: All voltages DC unless specified otherwise.