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Provides essential guidelines for safe operation during servicing of the TV receiver.
Details X-ray radiation sources and measurement procedures for safety during servicing.
Outlines mandatory safety measures and procedures for handling the receiver during service.
Instructions for removing the CRT and critical safety warnings for handling the picture tube.
Essential safety measures, required test equipment, and initial setup for adjustments.
Step-by-step guide for adjusting the purity of the CRT display using magnets.
Diagnostic steps for common issues like no raster, no picture, or no sound.
This document outlines the service and maintenance procedures for the LG COLOR TV, specifically models CT-21Q41KE/KEX/42KEX, which utilize the MC-019A chassis. It serves as a comprehensive guide for technicians, emphasizing safety, proper servicing techniques, and detailed adjustment instructions to ensure the television operates correctly and safely.
The television is designed for a range of viewing experiences, supporting various video input systems and tuning ranges, making it adaptable to different broadcast standards. Its control interface is user-friendly, featuring both a remote control handset and front panel buttons for easy navigation and adjustment of settings. The remote control allows for comprehensive control over the television's functions, including power, channel selection, menu access, volume, and special features like "EYE" function, "Q.VIEW," "TELETEXT," "PSM" (Picture Status Memory), and "TURBO PICTURE / SOUND." The front panel offers essential controls for power, menu, volume, and input selection, ensuring basic functionality even without the remote.
For optimal performance and longevity, the television incorporates several usage features. The "EYE" function, when available, automatically adjusts picture settings based on ambient light conditions, enhancing viewing comfort and potentially reducing power consumption. The "PSM" feature allows users to recall their preferred picture settings, providing a personalized viewing experience. Similarly, the "SSM" (Sound Status Memory) feature recalls preferred sound settings. The "TURBO PICTURE / SOUND" button offers quick access to enhanced picture and sound modes. For convenience, the television includes a sleep timer function, allowing users to set a duration after which the TV will automatically switch to standby. Connectivity options are robust, with multiple audio/video input sockets, including a headphone jack, and a PERI connector for full SCART functionality, enabling connection to various external devices like DVD players and game consoles.
Maintenance of the LG COLOR TV is crucial for safety and performance. The manual provides detailed safety precautions that must be observed during servicing, including the use of an isolation transformer to protect against electrical shock and the importance of replacing safety-related parts with specified components to prevent hazards like X-RADIATION, shock, or fire. Technicians are advised to handle the picture tube with extreme care due to its high vacuum and large surface area, emphasizing not to lift it by its neck. Regular checks for high voltage and AC leakage current are mandatory after servicing to ensure the set is safe for operation.
The adjustment procedures are meticulously detailed, covering critical aspects such as CDL data adjustment, option data adjustment, focus adjustment, screen voltage adjustment, and white balance adjustment. These adjustments ensure accurate color reproduction, proper screen geometry, and stable high voltage. For instance, the focus adjustment involves tuning the TV to a specific channel and adjusting the FBT's focus volume for the best picture clarity. Screen voltage adjustment requires connecting an oscilloscope to the CPT board and adjusting the FBT's screen volume to achieve a specified waveform, which is vital for preventing premature component failure. White balance adjustment, performed after screen voltage adjustment, ensures accurate color temperature and gray scale tracking.
Deflection data adjustment is another key maintenance feature, allowing technicians to fine-tune vertical linearity, vertical amplitude, vertical "S" correction, vertical shift, and horizontal shift. These adjustments are essential for correcting geometric distortions and ensuring the image fits correctly on the screen. The manual also provides a comprehensive guide for purity and convergence adjustment, which is critical for ensuring that the red, green, and blue electron beams converge accurately on the screen, producing a sharp and clear image without color fringing. This involves careful manipulation of the deflection yoke and beam bender magnets, with specific instructions to avoid disturbing purity adjustments during convergence procedures.
The document also includes exploded views and parts lists, which are invaluable for identifying and replacing components. Parts identified as "critical for safety" must be replaced with the exact specified part numbers to maintain the television's safety standards. General soldering guidelines are provided to prevent damage to sensitive components, emphasizing the use of grounded-tip soldering irons and anti-static solder removal devices. Instructions for removing and replacing various components, including ICs, transistors, diodes, fuses, and resistors, are detailed, along with procedures for repairing circuit board foil damage. These guidelines ensure that repairs are performed correctly and safely, preserving the integrity and functionality of the television.
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