Every sewing machine that I’ve ever seen has a check spring. The check spring is located just before the take-up lever, and takes slack out of the upper thread just as the needle is about to penetrate the fabric.
For some reason, many Bernina machines have a problem where the check spring tends to pop out of position. I don’t really know how this happens, but once it is popped out of position, the machine sews terribly. The machine operator may believe they have tension issues, and the machine may sound loud and rough. Unfortunately, adjusting the tension is not going to help the machine sew better.
For as many sewing machines as I have serviced over the last 12 years, I’ve seen this problem enough to call it a common problem. Take a close look at the image to the right. The check spring is not located in the space (or channel) between the take-up lever guard. Click on the image to enlarge it, and take a closer look.
Fortunately, it’s really easy to pop the check spring back into place. By simply removing the left end cover, you will have access to push the check spring back into place. I just use my finger. In most cases the check spring does not pop back out, and my customer sews happily for many hours. If the check spring does pop back out, then a new upper tension unit will need to be installed.
The second image, shown to the right, shows the check spring in its correct position. Click on the image to enlarge it, and take a closer look.
Both images were taken of a Bernina 153 that came in for service this week. This issue could apply to, but is not limited to, any virtuosa, artista, or activa sewing machine. Most Bernina machines made in the last 15 years could have a check spring problem as described in this post. It’s an easy fix, and hope this information helps somebody.
Posted in Bernina