The LG 42LK450 is a 42-inch LCD TV featuring Full HD 1080p resolution, built-in digital/analog tuner, multiple HDMI inputs, USB connectivity, energy saving technology, Clear Voice II for enhanced dialogue clarity, Intelligent Sensor for automatic picture adjustment, and various picture modes. Below are key sections for technical specifications, disassembly procedures, troubleshooting, circuit diagrams, and service adjustments.
Technical specifications and key components: LCD panel, power supply board, main board, T-CON board, backlight inverter, and various connectors.
| Specification | Details |
|---|---|
| Screen Size | 42 inches LCD |
| Resolution | 1920 x 1080 Full HD |
| TV System | ATSC/NTSC/QAM |
| Inputs | 3x HDMI, 2x Component, 1x Composite, 1x PC Input |
| USB Port | 1x USB 2.0 for media playback |
| Power Consumption | Typical 85W, Standby <1W |
| Power Supply | 100-240V AC, 50/60Hz |
| Backlight Type | CCFL |
| Sound Output | 10W x 2 |
| Dimensions | With Stand: 38.2" x 26.1" x 9.8" |
Step-by-step procedure for disassembling the TV unit for service and repair.
WARNING! Disconnect power before disassembly. Handle LCD panel with care to avoid damage.
Detailed circuit schematics for all major components and boards.
Common problems and solutions for the LG 42LK450 LCD TV.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No Power | Power supply failure | Check fuse F101, measure standby voltage, replace power board if necessary |
| No Backlight | Inverter or CCFL failure | Check inverter output, test CCFLs, replace faulty components |
| No Picture/Sound | Main board failure | Check main board voltages, reprogram or replace main board |
| Vertical Lines | T-CON or LCD panel | Check T-CON board connections, replace T-CON board |
| No HDMI Input | HDMI port or main board | Check HDMI port connections, replace main board if needed |
Printed circuit board layouts and component locations.
Main Board: Component side and solder side views with test points labeled.
Power Supply Board: Layout showing high voltage and low voltage sections.
T-CON Board: Component placement and connector pinouts.
Inverter Board: Transformer locations and output connectors.
Standard voltage measurements at key test points.
| Test Point | Normal Voltage | Tolerance |
|---|---|---|
| Standby 5V | 5.1V DC | ±0.2V |
| Main 12V | 12.0V DC | ±0.5V |
| Main 24V | 24.0V DC | ±1.0V |
| Panel VCC | 12.0V DC | ±0.5V |
| VGH | +25V DC | ±2V |
| VGL | -7V DC | ±1V |
Recommended replacement parts and part numbers.
Note: Always verify part numbers before ordering replacements.
Instructions for updating TV firmware and software.
CAUTION! Incorrect firmware may damage the TV. Use only official LG firmware.
Important safety information for service technicians.
ELECTRICAL SAFETY: Always disconnect power before servicing. Discharge capacitors before handling boards.
LCD PANEL: Handle with care - glass is fragile. Use proper anti-static precautions.
BACKLIGHT: CCFL tubes contain mercury - dispose of properly according to local regulations.
How to access service menu for adjustments and diagnostics.
WARNING! Only qualified technicians should access service menu.
Warranty terms and service contact information.
Standard warranty: 1 year parts and labor from date of purchase. Extended warranties available. For service under warranty, contact LG authorized service center. Out-of-warranty repairs available at standard service rates.
Service Support: 1-800-243-0000
Website: www.lg.com