Help with Brother 1204C

todd.embroidery

The thread keeps popping off of the sensor wheel. This is happening now on various needles at various times. This didn't used to happen at all. Any ideas why this is happening?

luke711

check the tension discs before and after the sensor wheel. If loaded with debris, clean out. Also sometimes the sensor wheel assembly gets worn out and wobbly-check that out

Miarobi

Perhaps you are installing the needle incorrectly or it has some kind of defect. Or maybe a low quality thread. This is one of the most primitive reasons. But of course, a bobbin case malfunction is also possible or the shuttle is out of balance