Small Appliance Repair Questions? Ask a Technician ASAP
Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
That is indeed a serious problem. And to be quite honest, it sounds as if it will not be curable readily, but may require (ultimately, after we try several things) a trip to a service shop.
But first, let us consider and try things.
- What sort of control do you change, to change or set the stitch length on your machine? is it a dial, or is it a digital control or setting on a screen?
- And, how old is your Bernina machine, please?
I must suggest, given the information you have provided, that you clean the machine out thoroughly, through all parts of the bobbin case and the stitching area.
I suspect this may not cure the problem, though. I would like to ask where you are located, by zip code, or by town/city and state, so that I may recommend you to a nearby and reputable servicing facility should my suggestions not produce a cure for the problem.
I am in the process of researching this problem's possible variants and aspects.
One minor suggestion: If the display of the stitch length setting ever turns pink, try to sew while it is in that state. It might, rather doubtfully, help. But it's a possible aspect of the problem.
Have you tried changing to a different needle, since this problem started?
Is there anything unusual about thread or fabric quality or density/heaviness?
Note: research indicates that if thread gets loose, and wraps around machine workings, it can 'throttle' or change the stitch length (among other things.) Perhaps that might be the problem's source... look into the needle mounting, with a flashlight, as much into it as you can without breaking anything, see if there's any sign of loose thread 'binding' or wrapped tightly, around that part of the machine's workings.