This document provides a comprehensive service manual for the LG LED LCD TV, specifically models 47LV3700 and 47LV3700-SA, built on the LJ12B chassis. It covers essential information for servicing, including safety precautions, technical specifications, adjustment instructions, and exploded views.
Function Description
The LG LED LCD TV is a display device designed for home entertainment, capable of receiving and displaying television broadcasts and various external video and audio inputs. It supports both digital (SBTVD) and analog (NTSC / PAL-M / PAL-N) receivable systems, covering a wide range of channels (VHF: 02 ~ 13, UHF: 14 ~ 69, DTV: 02 ~ 69, CATV: 01 ~ 135). The TV is designed for the North/Latin America, Europe/Africa, and Asia/Oceania markets.
The TV incorporates LED backlight technology, which contributes to its picture quality and slim design. It features local dimming capabilities, enhancing contrast by selectively dimming areas of the screen to achieve deeper blacks and brighter whites. Depending on the specific model variant (Edge LED or ALEF LED), the local dimming implementation varies in block configuration.
The device includes a main processor (BCM35230), DDR memory, and flash memory for its core operations. It supports multiple HDMI inputs (4:1 switch), audio amplification (10W+10W), and various audio/video input/output options such as Component Video, RGB (PC), SPDIF Out, and Earphone Jack. Connectivity features include USB ports (for DVR Ready and Wi-Fi), LAN (Ethernet), and RS-232C for service adjustments. Some models also support 3D TV functionality via HDMI 1.4a and 1.3a inputs.
Important Technical Specifications
- Chassis: LJ12B
- Screen Sizes: 32-inch, 42-inch, 47-inch Wide (1920x1080 resolution)
- Aspect Ratio: 16:9
- Tuning System: FS
- LCD Modules:
- 32LV3700: LC320EUN-SDV2
- 42LV3700: LC420EUN-SDV3
- 47LV3700: LC470EUE-SDV1
- Max Luminance (Center 1-point / Full White Pattern):
- Module: 290-360 cd/m²
- SET: 250-320 cd/m²
- Luminance Uniformity: 77%
- Contrast Ratio: 1000-1400 (NORMAL)
- Color Temperature (Cool/Standard/Warm): Specified x, y coordinates with ±0.015 tolerance for White Balance Adjustment.
- Input Voltage: AC 100-240V~, 50/60Hz
- Operating Environment: Temperature: 0 ~ 40 °C, Humidity: ~ 80%
- Storage Environment: Temperature: -20 ~ 60 °C, Humidity: -85%
- Component Video Input (Y, CB/PB, CR/PR): Supports resolutions from 720x480 (SDTV) up to 1920x1080 (HDTV 1080P) with varying H-freq, V-freq, and Pixel clock values.
- RGB Input (PC): Supports resolutions from 640x350 (EGA) up to 1920x1080 (HDTV 1080P) with specified H-freq, V-freq, and Pixel clock values. RGB PC Monitor Range Limits: Min Vertical Freq - 56 Hz, Max Vertical Freq - 62 Hz, Min Horiz. Freq - 30 kHz, Max Horiz. Freq - 80 kHz, Pixel Clock - 170 MHz.
- HDMI Input (PC/DTV): Supports resolutions from 640x350 (EGA) up to 1920x1080 (HDTV 1080P) with specified H-freq, V-freq, and Pixel clock values. HDMI Monitor Range Limits: Min Vertical Freq - 56 Hz, Max Vertical Freq - 62 Hz, Min Horiz. Freq - 30 kHz, Max Horiz. Freq - 80 kHz, Pixel Clock - 170 MHz.
- HDMI Input (1.4a) (3DTV): Supports 3D input modes like Frame packing, Side by Side (half), and Top and bottom for resolutions up to 1920x1080.
- HDMI Input (1.3a) (3DTV): Supports 3D input modes like Side by Side, Top & Bottom, and Checkerboard for resolutions up to 1920x1080.
- RGB Input 3D (PC): Supports WUXGA (Reduced Blanking) (Side by Side), Top and Bottom at 1920x1080.
Usage Features
- User-Friendly Interface: The TV likely features an intuitive on-screen display (OSD) for navigation and settings adjustment, as indicated by references to "Ez-Adjust Menu" and "Service Remocon."
- Automatic Adjustments: Includes features like automatic white balance adjustment and EDID (Extended Display Identification Data) auto-download for seamless integration with external devices.
- Diagnostic Tools: The service manual describes various test patterns (e.g., 100% Full White pattern, Horizontal Color Bar Pattern) and diagnostic menus (e.g., "Diagnostics menu on OSD," "Test pattern") to aid in troubleshooting and calibration.
- Remote Control Functionality: Supports remote control operations for power, menu navigation, and service adjustments.
- Connectivity: Offers a wide array of input ports (HDMI, Component, RGB, AV) and output ports (SPDIF, Earphone) to connect to various entertainment devices. USB ports enable DVR functionality and Wi-Fi connectivity on compatible models.
- Local Dimming: Enhances picture quality by dynamically adjusting backlight intensity in different screen areas, providing superior contrast.
- 3D TV Support: For specific models, it offers 3D viewing capabilities with various 3D input modes.
Maintenance Features
- Safety Precautions: The manual emphasizes critical safety measures, including the use of an isolation transformer during servicing, proper fuse replacement, maintaining component spacing, and performing AC leakage current checks to prevent electrical shock and fire hazards.
- Electrostatic Discharge (ESD) Protection: Detailed guidelines are provided for handling electrostatically sensitive devices, including grounding techniques, using grounded tools, and proper storage of components to prevent damage.
- Soldering Guidelines: Specific instructions for soldering and unsoldering components, including recommended iron temperature, solder type, and cleaning procedures, are outlined to ensure proper repairs and prevent circuit board damage.
- Component Replacement Procedures: Step-by-step instructions for removing and replacing various components, such as ICs, transistors, diodes, fuses, and resistors, are provided, with special attention to safety-related parts.
- Circuit Board Foil Repair: Techniques for repairing damaged copper patterns on circuit boards are described, including using jumper wires and careful soldering.
- Adjustment Instructions: Comprehensive procedures for factory adjustments, including MAC Address download, Component/RGB adjustments, EDID download, and White Balance adjustment, are detailed. These adjustments can be performed manually or via RS-232C commands.
- LAN Port Inspection (PING Test): Instructions for checking LAN port functionality using a dedicated test program.
- EYE-Q Function Check: A procedure to verify the functionality of the EYE-Q II sensor, which likely relates to automatic picture adjustments based on ambient light.
- USB Download: Instructions for updating firmware via USB stick using an *.epk file.
- Troubleshooting Flowcharts: The manual includes detailed repair process flowcharts for various error symptoms, categorized by high-level and mid-level descriptions (e.g., "No video/Normal audio," "Color error," "No power," "Wrecked audio/discontinuation/noise," "External device recognition error"). These flowcharts guide technicians through diagnostic steps, including checking voltages, cable connections, software versions, and replacing specific boards or modules.
- Visual Aids: Exploded views and diagrams of internal components and connections are provided to assist in assembly, disassembly, and identification of parts.
- Error Symptom Details: The manual provides specific content for each error symptom, such as checking backlight, LED driver voltage, white balance, power board voltages, tuner signal strength, LVDS cable connections, and adjustment test patterns. It also includes visual examples of common T-Con board and module defects.
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