When picking, see if the machine head is bright, whether there is stripping and bumping, whether the plating layer of the needle board, push plate, panel, upper wheel is intact;

1. Wipe all parts of the machine first; compete and check if 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, whether the protective dev......

ethods as below: 1. Change the needle first. 2. Drop the feeding teeth and see if there is pressure on the presser foot. 3. Open the two screws on the needle plate to remove the needle plate and follow: (1) Shake the handwheel on the right side and shake the needle bar to the lowest position (wh......