In the diverse commodity market, there is always a way to judge the quality of a product, and different consumers always have their own basis and attention to judgment. So for technology-based machinery and equipment, the correct choice is relatively more important. Servo coiling machines are important machinery and equipment in the wire harness processing industry, and judging their quality can be done through transistors. The judgment of the quality of a transistor can be carried out according to the following methods. Firstly, the judgment method for the base and tube type is used. The measured germanium tube uses the R × 100 range, and the silicon tube uses the R × 1K range. First, fix the red probe to contact any one of the pins, and measure the other two pins with the black probe separately to see if the smaller resistance value can be measured twice. Of course, this requires professional understanding and operation.