Sometimes thread gets itself buried in the bobbin case or in the tension disks. It takes just a tiny tuff of thread to cause all kinds of problems! Take a look with a flashlight with the bobbin and bobbin case removed. Look at the bobbin case itself too. Occasionally I use unwaxed dental floss and floss the tension disks, just to make sure I clean those out too.

Pam

Did you take out bobbin case and clean the machine, sometimes this does the trick

Many times, I have heard that rethreading helps, and it had helped me. Good luck with your machine, It's wonderful that you have a quilting friend nearby! That helps! Hang in there!

Perhaps if you can take your machine to your friends home. With her fresh eyes she may see something you are not....

Perhaps the bobbin just isn't seated correctly? Sometimes just that tiny bit is the problem. Take it out, check for dust bunnies and hidden thread, and then make sure it seats correctly when replacing. Also, make sure to change your needle.

In the meantime, have a GREAT time quilting with your friend.

oh, i'm sure you will enjoy quilting with your friend. maybe thats the way they were supposed to be. good luck with your machine and i hope it helps you to destress. :D