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在检修过程中,检测元器件好坏这一步相当重要。但有时会因检测工具等原因误将已损坏的元器件判为良好元器件。所以当怀疑易损件损坏,但用万用表检测却无异常时,不妨采用代换法试一下。故障现象:长虹 DT2000彩电,出现水平一条亮线。分析与检修:有光线,说明 CPU 及行扫描电路输出的数据信号正常,故障在场扫描电路,场扫描电路由TDA9332部分电路及 TDA8351组成,如图1所示。检测 TDA8351的各脚电压,发现除③、⑥脚外,其余脚电压均异常。断电后,检测 TDA8351各脚的对地电阻值均正常。又将偏转线圈等处补焊一遍仍无济于事,说明TDA8351自身无异常,故障点应在 TDA9332或TDA9332至 TDA8351之间的电路上。
In the overhaul process, testing components is good or bad this step is very important. But sometimes because of testing tools and other reasons, the damaged components will be judged as good components. Therefore, when the suspect wearing parts damaged, but no abnormalities detected with a multimeter, may wish to use the substitution method to try. Symptoms: Changhong DT2000 TV, there is a level of a bright line. Analysis and Maintenance: There are light, indicating that the CPU and the line scan circuit output data signal normal, the presence of fault scanning circuit, field scan circuit by the TDA9332 part of the circuit and TDA8351 components, as shown in Figure 1. TDA8351 detection of the voltage of each foot and found that in addition to ③, ⑥ feet, the other foot voltage anomalies. After power failure, the test TDA8351 feet of the resistance to the value of normal. Turn the other side of the deflection coil welding is still useless, that TDA8351 itself is no exception, the fault point should be TDA9332 or TDA9332 to TDA8351 between the circuit.