Deco 650 runs unbalnced

try using a can of air in the bobbin area, also check for lint or loose threads, make sure the bobbin is turned correctly in the bobbin case, try a different bobbin.

You need to take the machine to a Bernina dealer for service. It may just need the timing adjusted, or there could be something else that needs to be done.

Turn the little screw on the bobbin case.

The tensions are not calibrated properly. To get by, or if you do not want to take it back to the shop, just lower the upper tension a little at a time until it looks ok.
I have 25 years experience working on sewing machines

hi! there,
open needle plate if the shuttle race and the bobbins has been pull out that making noise,or accumulation of thread under bobbins, if nothing there, run machine and check if shuttle race and bobbins are moving,also with the needle if not,there are opening at the bottom of machine try to open if some gears are broken,or belt is slip.
if broken gears there a lot of parts before you can pull out gear, beside the timing order you cannot put back.this should be done by technician expert
in sewing machine.take this to service center.
cheers have a nice day just rate me.

You should use some klnd of stabilizer under your hoop. I use the paper kind which is thin or there is a heavier tear away stabilizer. I have used all cotton thread for embroidery or you can use rayon. There is a finer thread called bobbin thread for the bobbin but I gernerally use the same as on the top so it will be the same. Are you using an embroidery needle? .As for your thread getting wound around the bobbin the only thibng I can think of is tht it is threaded incorrectly. if it isn't the lack of a stabilizer. I hope this helps but I think it the the lack of stabilizer that is causingyour problems. The needle is going in and our of the same hole during embroidery and is getting stuck on your bobbin. Let me know if this helps! Suz

Jim!

Perfect phrasing of the question, you have all the lingo/parts down pat!

First make sure your new needle is straight, then check to make sure it lines up in the center of the hole in the stitch plate.

There is basically a 1/2 sheet of papers (we use the fine waxy sticker backing paper as our guages don't fit well .1mm! ) distance between the hook and the needle.

Rotate your hook so that it is aligned with the needle in the center position, there should be 2mm between the top of the needle eye and the bottom edge of the hook.

See if drive belt is not running against the plastic body on right side.!

It could be that there is a loose piece of thread, or some fluff which is obstructing the tension gauge. Try blowing around the theading area (or even run the hoover pipe near it to see if you can **** it out). I cleared mine by folding a piece of non fluffy material and rubbing gently between the tension dial and machine.

Good luck

Try a dry or powder lubricant in bobin case ,not to mutch ! You must try and remove plastic on right side ,to get to working parts ,do not spray on sensors!