The use of electronic components in circuits is very common, and it is inevitable that circuit faults will occur due to circuit problems during long use. Line detection often encounters many problems in the maintenance of electronic products. Usually, the circuit is checked with a multimeter, and the resistance value of the resistor indicated by the multimeter is used to judge whether the line is normal.

 Usually we will connect the two test leads of the multimeter to the starting point of the control circuit. After turning on the circuit, check the reading of the multimeter. If the resistance is 0Ω, the circuit has a short circuit. If the resistance has a certain value, the circuit is normal, and there is no short circuit was found. In this process, many line inspectors will take the resistance segmentation detection method to judge whether the circuit is normal, and the latter to determine which electronic component has a problem.

In the resistance segmentation detection method, the inspection of the main circuit is extremely important, and many circuit problems are caused by problems in the main control circuit and cannot be operated. Usually after the control circuit is checked, the main purpose is to check whether there is a short circuit in the main circuit. When the main circuit is inspected, the DC resistance of each phase winding of the motor is small, generally below 10 Ω, and the electric blocking should be selected as ×1 Ω. After connecting the motor, press the contactor contact bracket to simulate the contactor according to the working sequence of each contactor, and use the universal meter to measure the resistance between the main switch outlet points. The resistance should be equal and the motor should be between any two power leads resistance. If the resistance is zero, it means that the main circuit is short-circuited; if there is a large resistance or ∞, it indicates that the main circuit has poor contact or open circuit. 

After the above resistance sectional measurement method, if the resistance value meets the above rules, the circuit wiring is basically correct without serious faults (short circuit), the power-on success rate is high, and the level of the analysis and judgment circuit is also improved in the measurement process. If the above method still can't detect the problem of the circuit, then you can only choose to give up the repair and replace a new main circuit. Although the cost is a bit high, it can guarantee the smooth and long-term operation of the circuit. This situation is generally on the domestic washing machine. Circuit maintenance is mostly common, and many after-sales personnel choose to directly replace the main circuit.