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例30故障现象;TCL LCD32K73液晶彩电,VGA图像不良,有绿色的彩条干扰。分析与检修:开机测试,发现在VGA状态下图像有绿色的条状干扰。切换其他信号测试正常,故障现象只是在VGA状态下存在。根据信号流程图我们知道,VGA信号通过VGA插座进入后,直接耦合到超级芯片U100(MST718BU)处理。因为是绿色干扰,于是检测G信号的输入脚12、13,发现13脚没有G信号的波形,12脚正常,更换G信号输入耦合电容C123,通电测试13脚有波形,试机,故障排除。
Example 30 fault phenomenon; TCL LCD32K73 LCD TV, VGA image is bad, with green color bar interference. Analysis and overhaul: boot test, found in the VGA state of the image strip of green interference. Switching other signals test is normal, the fault phenomenon exists only in the VGA state. According to the signal flow chart we know that VGA signal through the VGA socket into the direct coupling to the super chip U100 (MST718BU) processing. Because it is a green interference, so the detection of G signal input pin 12, 13 found no signal waveform G, 12 feet normal, replace the G signal input coupling capacitor C123, power test 13 feet waveform, test machine, troubleshooting.