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该机的故障现象为开机三无。从电路上分析可知。本机在开关电源部分没有设置过流保护电路,当负载电流非正常增大时,很容易造成BG311和A301过载损坏,先检查各路负载对地电阻,+130V对地为17.5kΩ,+16V对地为0.75kΩ,+180V对地为50kΩ,+26V对地为16kΩ,均正常,说明负载无问题,故障在电源电路,查调整管BG311已损坏,测厚膜块A301各脚阻值及电压与正常值有明显的差别。A301各脚阻值及电压正常值如表1。表明A301也损坏。查
The failure of the machine boot three no. From the circuit analysis shows. The machine has no over-current protection circuit in the switching power supply part. When the load current increases abnormally, BG311 and A301 are easily overloaded and damaged. First, check the resistance of each load to ground. The ground resistance of + 130V is 17.5kΩ and + 16V Ground 0.75kΩ, + 180V to ground 50kΩ, + 26V to ground 16kΩ, are normal, indicating that the load is no problem, the fault in the power supply circuit, check the regulator BG311 has been damaged, the thickness of the film block A301 resistance and Voltage and normal there are significant differences. A301 each pin resistance and voltage normal value in Table 1. A301 also shows damage. check