LG 50PK250 Service Manual

The LG 50PK250 is a 50-inch Plasma TV featuring HD resolution, built-in digital/analog tuner, multiple input options including HDMI, component video, composite video, PC input, USB port, and various audio outputs. This service manual provides detailed technical information for service technicians including disassembly instructions, circuit diagrams, troubleshooting procedures, and replacement part information.

Product Specifications

Technical specifications for the LG 50PK250 Plasma TV.

Specification	Details
Display Type	50-inch Plasma Panel
Resolution	1366 x 768 (HD Ready)
Tuner	ATSC/NTSC/QAM Built-in
Inputs	3x HDMI, 2x Component, 2x Composite, 1x PC Input
Outputs	Digital Audio Optical, Analog Audio
USB Port	1x USB 2.0 for service and media playback
Power Consumption	350W typical, 0.5W standby
Power Supply	100-240V AC, 50/60Hz
Dimensions	48.1" x 30.9" x 3.9" (with stand)
Weight	62.8 lbs (with stand)

Safety Precautions

Critical safety information for service technicians.

1. Disconnect AC power before servicing - plasma TVs contain lethal voltages.
2. Use proper grounding equipment and anti-static precautions.
3. Plasma panels are fragile - handle with care during disassembly.
4. Allow sufficient cooling time before handling internal components.
5. Use only specified replacement parts to maintain safety standards.

WARNING! High voltages are present in power supply and sustain boards - discharge properly before servicing. Plasma panels contain hazardous materials - dispose of properly.

Disassembly Instructions

Step-by-step disassembly procedure for the LG 50PK250.

1. Remove stand: Lay TV face down on soft surface, remove screws securing stand.
2. Remove rear cover: Remove all screws from rear casing, carefully separate cover.
3. Disconnect cables: Note cable positions before disconnecting from main boards.
4. Remove main board: Unscrew mounting brackets, disconnect all cables.
5. Remove power supply: Discharge capacitors, remove mounting screws.
6. Access plasma panel: Remove front bezel carefully to access panel connections.

CAUTION! Handle plasma panel with extreme care - do not apply pressure to screen surface.

Circuit Diagrams

• Power Supply Circuit: Detailed schematic of AC input, rectification, and DC output stages.
• Main Board Circuit: Complete diagram of video processing, audio, and control circuits.
• Y-Sustain Board: Schematic for vertical scanning and sustain circuitry.
• X-Sustain Board: Diagram for horizontal scanning and sustain functions.
• Control Board: Circuit for panel driving and timing control.
• Logic Board: Interface between main board and plasma panel.

PCB Layouts

Printed Circuit Board layouts for all major components.

Main Board: Component placement and trace routing for video/audio processing.

Power Supply Board: Layout showing high voltage and low voltage sections with component identification.

Y-Sustain Board: Component placement for vertical drive circuitry with heat sink locations.

X-Sustain Board: Layout for horizontal sustain circuit with power device locations.

Control Board: Interface board layout showing connector positions and test points.

Voltage Measurements

Standard operating voltages at key test points.

1. Power Supply Outputs: VS: 195V, VA: 55V, 15V, 5V, 3.3V
2. Y-Sustain Board: Vscan: -95V, Vset: 165V, Ver: 125V
3. X-Sustain Board: Vbias: 105V, Vsch: 95V
4. Main Board: 12V, 5V, 3.3V, 1.8V digital supplies
5. Logic Board: 3.3V, 2.5V, 1.2V logic voltages

Tip: Use high impedance multimeter and proper grounding when measuring voltages.

Troubleshooting Procedures

Systematic troubleshooting flow for common issues.

1. No Power: Check AC input, fuse, standby voltage, power supply outputs.
2. No Picture/Sound: Verify main board operation, check video processing ICs.
3. Abnormal Colors: Test video DAC, check LVDS cable, examine panel drivers.
4. Image Retention: Check sustain boards, verify panel driving waveforms.
5. Audio Issues: Test audio amplifier, check speaker connections, verify audio processing.
6. HDMI Problems: Verify HDMI receiver IC, check input selection, test EDID communication.

WARNING! Always discharge high voltage capacitors before testing sustain boards.

Replacement Parts List

Authorized replacement components with part numbers.

Component	Part Number	Description
Main Board	EBR61553801	Complete main processing board
Power Supply	EAX61759401	AC/DC power supply board
Y-Sustain Board	EAX61760101	Vertical sustain and scan board
X-Sustain Board	EAX61760201	Horizontal sustain board
Control Board	EAX61760301	Panel control and timing board
Plasma Panel	50P3DC1D	Complete 50-inch plasma display module
Remote Control	AKB72915207	Original remote control unit

Adjustment Procedures

Factory adjustment and calibration procedures.

White Balance Adjustment: Access service menu, adjust R/G/B gains and offsets for proper color temperature.

Geometry Adjustment: Set proper scanning parameters and image positioning.

Color Decoder: Adjust color decoding for accurate color reproduction.

Audio Level: Set audio output levels and balance.

Panel Aging: Initial panel aging procedure for new plasma panels.

Firmware Update

Software update procedures for the LG 50PK250.

1. Download latest firmware from LG service portal.
2. Extract files to USB drive formatted as FAT32.
3. Insert USB drive into TV USB port while TV is off.
4. Enter service mode and select USB update option.
5. Do not interrupt power during update process.
6. TV will restart automatically after successful update.

CAUTION! Never interrupt firmware update - may cause permanent damage requiring board replacement.

Service Mode Access

Function	Access Method	Description
Service Menu	Menu + 0000 on remote	Access adjustment and test patterns
Factory Reset	Service Menu Option	Restore all factory default settings
Burn-in Reduction	Orbiter function	Activate pixel shifting to reduce image retention
Panel Test	Service Menu Pattern	Display test patterns for panel evaluation
Error Log	Service Menu Display	View stored error codes and history

Reset: Service Menu > Factory Reset > Enter password 0413

Technical Support: LG Service Hotline: 1-800-243-0000