Solution: After re-welding, the fault was eliminated. LG TV, a horizontal bright line appears on the screen.
Analysis and Maintenance: It is estimated that the fault lies in the field scanning circuit, Beijing LG TV Repair Center. This machine uses Philips TDA83625 type microcontroller, and TDA3654 as the field output block, where pin 8 is the feedback end. Measuring the voltage of pin 8 of TDA3654 with a multimeter shows 0V, while it should normally be 8.5V. Upon checking the voltages of other pins, they are all normal. Continuing to check along the circuit, it was found that there is no connection between pin 3 and pin 4 of the frame deflection coil. Careful inspection revealed that one foot of inductor L1200 has already detached from the printed circuit board.
Source of information: Beijing LG TV After-sales Service Phone Number http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3701288.