首先从电视机使用时间来分析,它肯定有元件变质或损坏,再从张歧文师傅的检修过程中可以分析出该机故障是由于滤波电容(C878)容量变小而引起的,因为开关电源的频率是照明电源的几十倍,如果滤波不好.电感L876会产生很大的的感抗,再加上稳压二极管VD848限制电压,所以在A点测量时有115V,而到B点就会下降 First of all, from the TV to use the time to analyze, it is certainly components deterioration or damage, and then from the master Zhang Qiewen overhaul can be analyzed in the aircraft fault is due to the filter capacitor (C878) smaller capacity, because the switching power supply frequency Is several times the lighting power supply, if the filter is not good. Inductance L876 will have a great sense of resistance, coupled with the regulator diode VD848 limit voltage, so when measured at A point 115V, and to B point will drop