When starting to sew, the thread goes down into the bobbin area and then gets tangled around the bobbin and breaks. Just ends with a knot being sewed

SOURCE: Timing

Question: How does one find the tension discs??? I have a White 1740 with a top drop in bobbin and I went thru the same problems as night_wolf above, then, ultimately, the top thread will now not pick-up the bobbin thread through the fabric. It picks up the bobbin thread without fabric in play, but once fabric is added (for free motion quilting) it won't pick it up. This is after using the machine for the last 10 days to piece and quilt without a problem until this morning.

I'm at a loss.
Tks, Candace

SOURCE: Upper thread knots up with bobbin thread when sewing a stich

Thread test
Test your thread quality to start, thread your machine and LIFT the presser foot (this opens the tension disks). Pull your top thread straight back. If you feel no tension no mater how much thread you pull, your thread is good. If that your machine passes that test, then let me know, we can go to step 2. If not, try different spool of thread, same test until you get a smooth pull (tip: always check your thread this way when you thread your machine)
Step 2:
Pull on your threaded bobbin thread while it’s in the machine. Does it pull smooth and even? If so, go to step 3. If not, try a new bobbin (bobbins get bent or distorted if wound too tight).
Clean thoroughly in the hook and bobbin case area and oil 1-2 drop is all.
Thread knotting on the bobbin can be a lot of things but here's some guidance:
Tension:
If the thread is loose on the bottom of the fabric, it's actually the top thread is too loose. Think of 2 little elves playing tug of war in your machine, one on toip and one underneath. If you have loops on bottom, the top needs to pull harder (tighten top tension)
Jamming bobbin case:
If it is damaged from turning out of place once, it could have rough spots on it that makes the thread hang on it, and keeps making it turn over and over. Use a finger nail board (fine sanding) and smoothall rough spots. Then reset the bobbin case taking care to put the notch in the bobbin case in alignment with the proper spot in the machine (basically 5 o’clock) when looking at the round area where the bobbin case goes.

SOURCE: thread knotting around bobbin case

hello, I had the exact same problem and could not find the solution until i took my machine to my sewing sensei and i solved my tedious problem. It was actually not a tension problem at all but a threading problem. Make sure you have threaded your bobbin correctly and that when you pull on the bobbin thread that the bobbin turns the right way. (mine must spin anti clockwise to work)  Make sure that when you pull up the bobbin thread using the needle that it is not over the feed dogs connective bar but under it. A big problem when the thread gets caught around the bobbin case wheel is that the thread is looped around the feed dogs once and that causes the thread to get caught around the bobbin wheel. In conclusion, thread the bobbin correctly and read over your instruction book before spending the money to get it fixe in s shop.

SOURCE: lower bobbin thread gets tangled

try changing the needle --make sure the needle is the right one
for the fabric being sewed
try a different thread
make sure the bobbin is not over filled
make sure the bobbin is turned the right way in the bobbin case
make sure the thread has not come off the thread take up lever