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最近维修几台德生收音机,均出现一打开电源开关便发出最大音量的广播声音,调节音量电位器无效,经换电位器后故障均排除,这是因为电位器内部的接地端与碳膜开路引起的。为什么电位器的故障率如此之高呢?不难理解:因为在这些收音机中的电位器与电源开关设在了一起,只有先拨动音量电位器打开电源开关,此时音量在最小位置,然后方可逐渐打开音量,往往打开电源开关时需用一点力去拨动音量电位器,若长期频繁受力之后容易将电位器内部弹片变形或弄
Recent maintenance of several German students radio, there is a power switch will open a maximum volume of the broadcast sound, adjust the volume potentiometer is invalid, after the replacement of the potentiometer fault are ruled out, this is because the potentiometer internal ground and carbon membrane open caused. Why potentiometer failure rate is so high? It is not difficult to understand: Because these radios in the potentiometer and the power switch together, only the first toggle the volume potentiometer to open the power switch, then the volume at the minimum position, and then Before gradually opening the volume, often need to open the power switch to force a little bit to dial the volume potentiometer, if the long-term frequent force easily after the deformation of the internal shrapnel or get