1. Wipe all parts of the machine clean first, and check whether the fastening parts between the parts are loose.
2. Check whether the oil L is unobstructed and lubricate according to the lubrication requirements.
3. Check whether there are any obstacles in each moving part and whether the protective device is intact.
4. Check whether the position between the presser foot and the needle, and between the presser foot and the feed dog is reasonable.
5. After the above preparations are confirmed, the power can be connected, the presser foot is raised, the empty car is running, and the direction of the handwheel is checked. If it is not correct, the power supply should be adjusted.