are you sewing the same level of thickness or the same type of fabric, if you are sewing a different level of thickness or even different fabric, you have to adjust the tension, also make sure to clean lint out of the machine, and rethread both bobbin and top. hope this helps

Make sure your presser foot is down when you adjust the top tension.

Wha-a-a-aWho-o-o-o for you! I know the feeling of working hours with finding that little piece of thread, lint or whatever the machine decided it did not like. Seems those little gears and levers have a real mind of their own. Glad you got it fixed.

I have a can of compressed air that I use to clean out the bobbin area. Just dont watch too close or you will end up with lint up your nose, in your eyes or in your mouth.

I have 2 babylocks and have not had the problem...if you are under warenty you can take it to any babylock dealer... check the internet to see the one near you....I had a bobbin case nick on my Ellageo, bought in Fl., I took it to a dealer in NC and they sanded my bobbin case for me and it worked fine love my Adury it was my Christmas present this year form my DH...He saw me sitting watching my big machine embroidery and ask me what could I be doing if I had a smaller machine...You have to remember we live in a RV...I told him I could sew...sew...sew
he is one who enables....He loves to go so we are always finding new QS or on our way to Joanns or Handcocks....he is a keeper.

It sounds to me as if your top thread is too tight, therefore, not being pulled to the middle of the thickness you are stitching. If the top tension is set above zero, you might consider giving it just a nudge toward zero. At the same time, tighten the bobbin tension 1/4 turn. Always adjust the top tension with the presser foot down.

If the top tension is 4 or 5 above zero, turn it at least 2 numbers toward zero and try this before doing anything to the bobbin tension.

As you pull both threads from the threaded machine with your hand (presser foot up), they should both pull with the same amount of tension.

Hope this helps.

I keep a hand vac ready to go between my two machines. The other day I cleaned that bobbin area at least 3 times and while it still sewed okay, I could tell by the sound there was some junk in there somewhere.

I looked, vacuumed, tried pipe cleaners, brush, pulled all apart that I could, wiped it with a nice clean cloth, put it back together. Sewed great for about 6 inches and there was the noise again!

I figured I'd try one more time and if that didn't do it, I'd sew until it broke. Then we'd be able to see what was causing the problem. EXCEPT this time, I taped part of a toilet paper tube to the end of the already small end so it was just a smidgen of suction area. That did it!

Wherever and whatever it was just popped right in there and it's been great ever since. I have no idea where that "piece" was lurking, but it was big enough to make a sound!

I immediately ordered one of those small area tube attachments which came today and is even smaller than my toilet paper tube one.

My little Fuller hand vac and I are getting to be great friends.

It sounds like you need a computer adjustment. This happened to me a few years back. 5 minutes and the repairman was done.

It sounds to me like the tension on the bobbin case is off. It sounds like it is too loose. Try taking the bobbin case with the bobbin in it and threaded the normal way and lay it flat in the palm of your hand. Make sure your hand is out flat. Now take the thread and lift up the bobbin case with it. The bobbin should almost, but not quite, come off your hand. If it comes up off your hand then it is too tight and if it unwinds too easy, it is too loose. The bigger of the two screws on your bobbin case is what adjusts the tension. Good luck. Hope this helps

Rethread the bobbin and brush and blow out every area where the bobbin sits.