Bobbin sensor problem, should be a new topic.


Jim Stutsman
 

The bobbin sensor works by pushing the little "flipper" on the bobbin case out until it stops. As it's moving, inside the machine there is a metal strip with slots cut in it. As the flipper moves, the strip goes through a light beam and the computer counts how many times the light beam was broken between slits. It doesn't have many moving parts. If the flipper isn't moving, that's an internal issue that you cannot do anything about other than go to your dealer. This could also be the case if accumulated lint in the machine is blocking the light beam. That requires disassembly and cleaning. Depending on your level of comfort, you could lay the machine on its back and remove the two Phillips (crosspoint) screws holding the bed cover in place. Of course the embroidery unit must not be on when you do this. Vacuum out all the lint that you can, then replace the cover. That's as far as you should go - anything more is dealer territory.

The other thing to look at is how the system works in embroidery. When you start a design, the flipper will measure the remaining bobbin against the number of stitches in the current color. If it looks like you will run out, you get a warning. On some designs, such as lace, the first color may have more than one bobbin's capacity in stitches. You'll get a warning, even with a full bobbin. Whether you think it's an error or not, you have to continue. At some point the bobbin will run out, without stopping the machine or issuing a warning. That's because during embroidery they don't keep checking the bobbin like they do in regular sewing. You can see this when you do regular sewing. At the end of nearly every seam you'll hear the click as the bobbin sensor checks. Some machines, e.g. Pfaff, use an optical sensor on the bobbin and will trip when it runs out in any mode. The top load of Janome machines is not really suited to that kind of sensor, so we get what we've got.


Fiona Williams
 

Hi Jim,

Thank you so much for your input. I just had the machine serviced so lint should not be a problem. I read something online about resetting it, turn machine off then turn back on holding start/stop button, mention may have to do this 5 or 6 times but wasn’t sure if I should try it.

Fiona


On Jan 27, 2022, at 8:50 AM, Jim Stutsman via groups.io <onlinesewing@...> wrote:

The bobbin sensor works by pushing the little "flipper" on the bobbin case out until it stops. As it's moving, inside the machine there is a metal strip with slots cut in it. As the flipper moves, the strip goes through a light beam and the computer counts how many times the light beam was broken between slits. It doesn't have many moving parts. If the flipper isn't moving, that's an internal issue that you cannot do anything about other than go to your dealer. This could also be the case if accumulated lint in the machine is blocking the light beam. That requires disassembly and cleaning. Depending on your level of comfort, you could lay the machine on its back and remove the two Phillips (crosspoint) screws holding the bed cover in place. Of course the embroidery unit must not be on when you do this. Vacuum out all the lint that you can, then replace the cover. That's as far as you should go - anything more is dealer territory.

The other thing to look at is how the system works in embroidery. When you start a design, the flipper will measure the remaining bobbin against the number of stitches in the current color. If it looks like you will run out, you get a warning. On some designs, such as lace, the first color may have more than one bobbin's capacity in stitches. You'll get a warning, even with a full bobbin. Whether you think it's an error or not, you have to continue. At some point the bobbin will run out, without stopping the machine or issuing a warning. That's because during embroidery they don't keep checking the bobbin like they do in regular sewing. You can see this when you do regular sewing. At the end of nearly every seam you'll hear the click as the bobbin sensor checks. Some machines, e.g. Pfaff, use an optical sensor on the bobbin and will trip when it runs out in any mode. The top load of Janome machines is not really suited to that kind of sensor, so we get what we've got.