Originally Posted by Cari-in-Oly

You beat me posting. That's what my first thought is too, symptoms are exactly what happened to me with my first embroidery machine. After the first few times it happened, I got to where I could hear it from the bobbin case when the thread was gonna break. It was in fact the thread was breaking when the spool jerked and the thread wrapped around the spool pin. Didn't matter whether I was using the horizontal or the vertical spool pin. Putting the spool in a cup behind the machine until I got a thread stand solved all my thread problems.

Cari