Just check step by step, check whether the bolt and wire are electrified, that is, whether the point enters the inside of the bushing, then check the switch and fuse to see if the switch is faulty or the fuse is blown, and then check whether the transformer is normal (if any). If the circuit is used straight, just check whether the rectifier silicon pile is broken, and the same is basically true for electrical power failure. Careful inspection will always find the fault point, which really helps you look forward to it. Just check step by step, check whether the bolt and wire are electrified, that is, whether the point enters the inside of the bushing, then check the switch and fuse to see if the switch is faulty or the fuse is blown, and then check whether the transformer is normal (if any). If the circuit is used straight, just check whether the rectifier silicon pile is broken, and the same is basically true for electrical power failure. Careful inspection will always find the fault point, which really helps you look forward to it.