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 video and pictures provided by your company, the engineering department of our company simulates the problem to reproduce the experiment, and 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 refer to 1k-2k resistance, output signal 1K-10K (please see the picture)2. Please return it first. The 220pcs servo that you think is not working at all 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!