I see that you have tried everything. I have a couple of small Brothers too and sometimes I don't realize that the bobbin thread jumps out of that little hook thing in the bobbin case and it causes very wonky stitches. I always think I have done it correctly and maybe I have but it jumps out. Maybe if you haven't checked that it is a possibility? The Brothers are usually trouble free so I hope your problem is easily fixed. Keep us posted.

Would it help if you looked at the YouTube tutorial about tension by Jamie Wallen? If this tip does not work, then a trip to the sewing repair store may be warranted. Good luck.

Alyce.... I want to say thank you, thank you, thank you
I just tried that and realized that the last little area that the thread is supposed in go in has a little bent edge. I put in the bobbin and the problem was there...took it out and used a couple of small knives to get the bent area smoothed out. Popped everything back, said a prayer and started to sew. OMG...it was perfect! You wouldn't think that such a tiny little bit of a bent would cause such problems. I would not have noticed it if I hadn't been watching carefully to make sure the thread was going into that little hooked area. It didn't pop out but I think the thread was hooked a bit on the damaged edge. I had taken the bobbin out of that case a dozen times but didn't examine the case carefully. I am so, so relieved! Can you tell I am happy!

Had to take a minute to post here to let you all know the problem was fixed and to tell you that you are all such wonderful people. No matter who asks or what is asked, there is always plenty of people to pop on and give help and advice.

So glad to hear! You know, it is always the last thing you try!!!!

Great news!