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我们的维修店里经常会碰到一些“三无”故障的彩电,根据经验它们大多是电源部分出了故障,且多为保险丝熔断、开关管击穿的恶劣故障。修理这种故障的关键点是在于找出开关管损坏的原因,否则刚换好的新管将有可能再次被击穿。而开关管损坏的原因却是多种多样的,电源电路中每一个元件的微小变化,例如取样电路中的滤波电容性能变差等,都可造成开关管基极输入的脉冲变劣,从而使开关管导通的时间延长、功耗增加,最终导致损坏。并且像上述的元件其微小变化
Our repair shop often encounter some “three no ” fault color TV, according to experience most of them are the power part of the fault, and mostly fuse blown, switch breakdown of the harsh fault. The key point to repair this failure is to find out the reason for the switch damage, or just replaced the new tube will likely be breakdown again. However, the reason for the switch damage is varied. Small changes in each element of the power supply circuit, such as poor performance of the filter capacitor in the sampling circuit, can cause the pulse input to the base of the switch transistor to deteriorate, Switch on the extension of time, power consumption increases, eventually leading to damage. And like the above-mentioned components its slight changes