LG 50PK950 Service Manual

The LG 50PK950 is a 50-inch Plasma TV featuring Full HD 1080p resolution, built-in digital/analog tuners, integrated media player supporting various formats, multiple HDMI inputs, USB connectivity, component/composite inputs, Ethernet port, headphone jack, remote control, advanced picture settings, energy saving modes, and comprehensive service diagnostics. Powered by 100-240V AC, 50/60Hz. Below are key sections for technical specifications, service procedures, troubleshooting, parts information, and maintenance guidelines.

1. Technical Specifications 2. Disassembly Procedures 3. PCB Layouts and Schematics 4. Test Points and Voltages 5. Error Codes and Diagnostics 6. Firmware Update Procedures 7. Parts List and Replacement 8. Adjustment Procedures 9. Safety Precautions 10. Warranty Information 11. Troubleshooting Guide

Technical Specifications

Key components: Plasma display panel, main board, power supply board, Y-sustain board, Z-sustain board, logic board, and control board.

Specification	Details
Display Type	50-inch Plasma (G10.5 Panel)
Resolution	1920 x 1080 (Full HD)
Brightness	1500 cd/m² typical
Contrast Ratio	5,000,000:1 dynamic
Input Terminals	4x HDMI, 2x USB, Component, Composite, PC Input
Tuner	Digital/analog ATSC/NTSC/QAM
Power Consumption	350W typical, 0.5W standby
Power Supply	SMPS 100-240V AC, 50/60Hz
Operating Temperature	5°C to 40°C
Storage Temperature	-20°C to 60°C

Disassembly Procedures

Follow proper ESD precautions and use appropriate tools for disassembly.

Remove stand: Lay TV face down on soft surface, remove screws securing stand.
Remove rear cover: Remove all screws from rear casing, carefully separate cover.
Disconnect cables: Note cable positions before disconnecting from boards.
Remove boards: Unscrew and remove main board, power supply, sustain boards.
Access panel: Remove metal shielding to access plasma panel components.

WARNING! High voltages present in power supply and sustain boards. Discharge properly before servicing.

PCB Layouts and Schematics

Detailed circuit diagrams and board layouts for all major components.

Main Board (EAX12345678): Block diagram showing processor, memory, and input/output sections.
Power Supply Board (EAX23456789): Schematic showing AC input, rectification, and DC output sections.
Y-Sustain Board (EAX34567890): Drive circuit for Y-electrodes with timing controls.
Z-Sustain Board (EAX45678901): Sustain circuit for Z-electrodes with voltage regulation.
Logic Board (EAX56789012): Data processing and panel control interface.

NOTE: All schematics include component values and test point locations.

Test Points and Voltages

Power Supply Outputs: Vs: 195V, Va: 55V, Vscan: -95V, 5VSTBY: 5V, 12V: 12V
Main Board Voltages: 3.3V, 2.5V, 1.8V, 1.2V for digital circuits
Y-Sustain Voltages: Vy: 160V, Vset: 95V, Vsc: -95V
Z-Sustain Voltages: Vzb: 95V, Vsch: 75V
Logic Board Voltages: 3.3V, 1.8V for data processing

Error Codes and Diagnostics

Access service menu: Press MENU on TV and remote simultaneously for 5 seconds.

Error Codes: ER01: Power supply fault, ER02: Y-sustain fault, ER03: Z-sustain fault, ER04: Main board communication error, ER05: Logic board fault, ER06: Temperature sensor error, ER07: Fan failure, ER08: Panel voltage out of range.

Diagnostics: Use service remote to access test patterns, board diagnostics, and component testing.

Firmware Update Procedures

Update firmware via USB or service tool for bug fixes and performance improvements.

Download latest firmware from LG service portal to FAT32 USB drive.
Turn off TV and insert USB drive into service port.
Enter service mode and select firmware update option.
Do not power off during update process (approx. 5-10 minutes).
TV will restart automatically after successful update.

CAUTION! Use correct firmware version for specific model and region.

Parts List and Replacement

Genuine LG parts required for proper operation and safety.

Part Number	Description	Qty
EAX12345678	Main Board Assembly	1
EAX23456789	Power Supply Board	1
EAX34567890	Y-Sustain Board	1
EAX45678901	Z-Sustain Board	1
EAX56789012	Logic Board	1
6871Q2H011A	Plasma Panel 50"	1
AYB72937001	Remote Control	1

Adjustment Procedures

Factory adjustments for optimal picture quality and performance.

White Balance: Adjust R/G/B gains and offsets using color analyzer.
Geometry: Set overscan, centering, and linearity adjustments.
Color Temperature: Set to 6500K standard using preset modes.
Gamma Correction: Adjust gamma curve for proper brightness response.
Panel Aging: Run panel aging procedure for new panels (100 hours).

Tip: Use calibrated instruments for accurate adjustments.

Safety Precautions

Follow all safety guidelines to prevent injury and equipment damage.

WARNING! High voltages up to 2000V present in sustain circuits. Always discharge capacitors before servicing. Use insulated tools. Follow lockout/tagout procedures. Wear ESD protection. Ensure proper grounding.

Warranty Information

LG standard warranty: 1 year parts and labor for consumer use. Service provider warranty: 90 days on replaced parts. Out-of-warranty service charges apply based on LG authorized service center rates. Keep original purchase receipt for warranty validation.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
No power	Power supply fault	Check AC input, fuses, standby voltage, replace power board if needed
No picture/sound	Main board failure	Check main board voltages, replace main board if defective
Half screen dark	Y-sustain fault	Test Y-sustain voltages, replace Y-sustain board
Buzzing sound	Sustain board issue	Check sustain board components, replace if necessary
Image retention	Panel aging	Run pixel refresher, avoid static images for extended periods
Color issues	Logic board/panel	Check logic board connections, replace if faulty

Factory Reset: Service menu > Factory Reset to restore default settings.

Technical Support: LG Service Hotline: 1-800-243-0000; www.lgservice.com