sebb

Hi,

I hope I can get some answers here as the tips found on internet didn't help.

This happens only sometimes and I'd like to know why. As you can see in the photo, it started making a huge knot underneath and the machine was going crazy, could only stop it from the power off button.

Can't blame it on tension or on wrongfully threading the upper thread or bobbin, since it did everything ok with this color until the last part.

Appreciate any help I can get.

sewingpup

sounds similar to a pfaff I had. It would just start stitching like crazy and I could not turn it off except to unplug it. I also had a bernina that made those fantastic bird's nest on the underside seemingly totally randomly while I was stitching. The Pfaff, I brought in a couple of times and as it is random, it never misbehaved for the tech and checked out fine when tested. The Bernina was brought in several times, the tech finally tweaked the timing a bit, but it still happened, that one I traded it in for another bernina that is working just fine. The pfaff tech said that the newer machines have such fine settings that even a spec of lint or static can cause them to behave strangely. I had brought him in a old 1950 ish Singer 66 and he said he loved working on them cuz he did not have to be that precise. If you can bring it in and if you can take photos on your phone of what happened and even, if you can, leave the work in the machine and bring it to the shop. That helps the tech figure stuff out.
Oh, another thing is to check the thread you are using. You need a good quality thread to do embroidery and even then, you can get a bad spool.

Rhonda K

Does it happen on different designs? It may be the design is dense in that spot.

Is the bobbin low? My machine gets cranky sometimes when the bobbin starts to run low.

Is there any thread in the bobbin area? Even a small piece can cause issues.

Is the machine set to cut the jump stitches? Is the cutter working?

I would cut out all the bad orange stitches in that one spot on the back and restitch just that section. Slow the machine down so you can catch and stop the machine when needed.

Just an FYI: You may want to add a layer of WSS clear topping on dense designs. It keeps the stitches from sinking into the fabric. It is not necessary but just a tip.