If the Xiaomi Robot Vacuum S40 cannot be turned on, please refer to the following steps to troubleshoot:
1. Check if the power of the device is insufficient. Please charge it on the charging dock before use;
2. Examine the charging contacts on both the robot vacuum and the dock for any dirt or debris. Clean them gently with a dry cloth to ensure a good connection;
3. If the ambient temperature is too low (below 0°C) or too high (above 40°C), it will result in the issue of not powering on. Please use it in a proper environment of 0 to 40°C.
If none of the above methods resolve the issue, please contact the local after-sales service center for further assistance.