A TCL-42 inch LCD color TV has a black screen with a sound fault. The test machine found that there is no common brightening and extinguishing phenomenon when the power is turned on. The backlight is completely off. The disassemble check backlight constant current board power supply 24V normal, the second boost is in At the moment of booting, the voltage of 200V will slowly fall back. This machine uses high-voltage full-series light bar for LG-42 inch screen. All the lamp beads and light bars are powered in series. There are only two power cables. The disadvantage is that they are only one. Only the light bar or lamp bead is open or damaged, which will cause a black screen. For this type of light bar, it is generally difficult to measure whether it is a light bar itself or a constant current plate by a multimeter. This machine is measuring two output plugs of the light bar. When the line is low, only a small voltage swings back slightly. For those who have no experience, it is often judged to be a constant current board problem, and it is not bright at the start. The best way is to have a light strip test equipment to quickly judge the fault. Part. The following is a picture of the maintenance process. For the dismantling of the screen, it is basically careful and meticulous. Pay attention to the position of the parts, cleaning, etc. There is not much difficulty here. It is not repeated here. The following is the picture of the maintenance process.
Guangdong Ojun Technology Co., Ltd. , https://www.ojunconnector.com