Accidental jump needle. Reason 1: machine needle hairiness, machine needle bending, machine needle groove is not smooth or improper selection. Troubleshooting: replace the appropriate needle.

In the absence of any schematic conditions to a relatively unfamiliar circuit board maintenance, the previous so-called "experience" will be difficult to do, although the deep hardware of confidence in...

Analysis: broken tip of machine needle, excessive tension of bottom line, improper adjustment of differential mechanism.

St. Thomas of England invented the hand sewing machine for sewing the single chain stitch of boots and shoes. This sewing machine is made of wood and some parts are made of metal.