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1.故障现象:三洋 A3分立元件开关电源,屡烧开关管及交流保险管、电源激励管、大功率电阻。故障检修方法和维修实例:(见图1)。(1)若开机瞬间屡烧开关管,检查代换300 V 滤波电解电容。300 V 滤波电容失容(表面大多有变形),使其两端含有大量的高频脉冲,在开关管截止期间与反峰电压叠加后,导致开关管过压损坏。如:海信TC2125C 型(三洋 A3系列机心)彩电中的 C507。(2)更换+130 V(115 V)整流二极管。(3)开机瞬间屡烧开关管,同时在开关电源中有多个元件损坏。要重点查换 R519(22Ω或27～47Ω)、R526(2.7 kΩ)、R524(39Ω)、R510(0.22Ω)、R517(1
1. Symptom: Sanyo A3 discrete components switching power supply, switch and repeatedly burning switch fuse, power excitation tube, high-power resistors. Troubleshooting methods and repair examples: (see Figure 1). (1) If the power switch instantaneous burn switch, check replace 300 V filter electrolytic capacitor. 300 V filter capacitor loss of capacity (most of the surface deformation), so that both ends contain a large number of high-frequency pulse, the switch deadline with the anti-peak voltage superimposed, resulting in over-voltage switch damage. Such as: Hisense TC2125C type (Sanyo A3 Series Movement) color TV C507. (2) Replace the +130 V (115 V) rectifier diode. (3) burn the switch instantaneous start-up at the same time, there are multiple components in the switching power supply damage. R519 (22Ω or 27 ~ 47Ω), R526 (2.7kΩ), R524 (39Ω), R510 (0.22Ω), R517 (1