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故障现象:一台创维数码8000T—2198型彩电,开机“三无”,但机内发出“吱吱”叫声。检修:开盖检查,发现“吱吱”叫声是由开关变压器T601发出的,说明开关电源已起振,而且振荡频率偏低测量+B端电压为50V左右(正常110V),为判断+B电压过低是开关电源还是负载电路故障,采用“假负载”检修方法:断开行限流电阻R330(该机实为一跨接线),在+B输出端,即Q605e极与地并接
Symptom: a Skyworth Digital 8000T-2198 color TV, boot “three noes”, but the machine issued a “creak” sound. Overhaul: Open lid inspection and found that “creak” sound is issued by the switch transformer T601, indicating the switching power supply has started, and the oscillation frequency is low Measurement + B terminal voltage of about 50V (normal 110V), to determine the + B Voltage is too low is the switching power supply or load circuit failure, the use of “false load” maintenance methods: Disconnect the trip current limiting resistor R330 (the machine is actually a jumper), + B output, that is, Q605e pole and ground