According to the question raised by

According to the question raised by your company, the engineering department of our company inspected the inventory (the product is the same as the product shipped by your company) and no problem with your company’s feedback was found. Springrc has never had such a serious problem since its operation, and the products shipped by our company must be 100% tested before shipment. It's incredible to have such a major defect problem! 1. According to the question raised by your company, the engineering department of our company found that when the resistance is too large, it will cause the servo to not receive the signal and cause it to not work. Please adjust the test standard and test according to the normal resistance standard. （(please check the picture)）If the resistance on the controller is too large, our signal may not be recognized. The IO of the single-chip microcomputer needs a certain drive current. You can try to change the resistance to 1K or 2K.2. Please return the 220pcs servo that your company thinks is not working at all, and it will be analyzed and tested by our company. 3. Please provide us with a 10pcs servo confirmed by your company as a good product for comparison, analysis and testing by our company. Please cooperate with your company for the above requirements, thank you!