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[例1]故障现象:长虹PT4288型彩电,指示灯亮,“二次”开机后,能听见继电器吸合的声音,屏幕无光栅,2s后,回到待机状态。分析与检修:指示灯亮,说明电视机的电源板STB5V电路工作正常,怀疑故障范围在信号主板和屏电路上。为缩小故障范围,对主板进行更换,故障依然存在,说明故障应该在屏电路上。对屏上组件检查后,发现电源板除STB5V电压正常外,其他电压均无输出。取下电源板,测量后发现各组电压对地电阻正常。将插座P12的⑩脚和ICl70的輷輦訛脚对地短路,通电瞬间各
[Example 1] Symptom: Changhong PT4288-type color TV, light, “twice ” boot, the relay can hear the sound of the pull, the screen without grating, 2s, back to standby. Analysis and Maintenance: Indicator light, indicating that the TV power supply board STB5V circuit is working properly, suspect the fault range in the signal board and the screen circuit. In order to narrow the fault range, replace the motherboard, the fault still exists, indicating that the fault should be on the screen. On the on-screen component inspection, found that the power board except STB5V voltage is normal, no other voltage output. Remove the power board, the measurement found that the normal voltage to ground resistance. The socket P12 ⑩ feet and ICl70 輷 辇 Erroneous feet short to ground, the power of the moment