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一台2188彩电遭雷击后系统控制集成块IC1102MN15151TWE(29)脚电源控制功能丧失,一般修理应更换芯片。本例修理利用IC1102⑩脚视频静噪控制端的电位变化恢复电源开关功能。该脚正常工作期间呈低电位,遥控关机后呈高电位,与(29)脚一样,但在换台时也有0.5s左右的短时间低电位静噪使屏幕呈现全黑,如果直接将Q803电源控制管基极接上来,就会在换台时关断电源,无法正常工作。为此在Q803基极加入简单延时电路如图1,使在换台期间基极电位不足以上升至Q803导通。RC时间
A 2188 TV was struck by lightning system control IC1102MN15151TWE (29) feet power control function is lost, the general repair should replace the chip. This case repair IC1102⑩ foot video mute control side of the potential change to restore the power switch function. The foot during normal operation was low potential, the remote control was high after the shutdown, and (29) the same foot, but when there is a change of Taiwan about 0.5s short period of low-voltage noise so that the screen appears all black, if the Q803 power supply When the control tube base is connected, it will turn off the power when changing stations, and can not work normally. To this end in the basic Q803 add a simple delay circuit shown in Figure 1, so that the base potential during the change is not enough to rise to Q803 conduction. RC time