2
  PROBLEM   CAUSE      REMEDY        REFERENCE 
 
  3. Breaking   1. Initial sewing speed is too fast.    Start with medium speed.
    upper thread 
      2. Thread path is incorrect.     Use the proper thread path.
    
      3. Needle is bent or dull.   Replace with a new needle. 
      4. Upper thread tension is    Adjust upper thread tension   P. 8
        too strong.   correctly.
      5. Needle size is inappropriate    Use appropriate needle and 
        for fabric.    thread for fabric in use.  
      
      6. Needle eye is worn.    Change the needle.
      7. Needle hole in needle plate is   Repair the hole or replace the 
        worn or burred.   needle plate.
  4. Breaking  1. Incorrectly thread bobbin case.   Thread bobbin case correctly.
  bobbin thread     
      2. Too much thread is around on   Adjust the position of stopper.
    the bobbin.   
      3. Lint is stuck inside the hook     Clean the hook race. 
    race.
      4. Thread quality is too low.    Change to a high quality sewing
      thread.
      5. Thread is jamming around the    Clear out the jamming thread.
        bobbin.   
      6. Bobbin thread tension is too   Adjust bobbin thread tension   P. 9
    strong.   correctly.
  5. Needle  1. Needle is hitting the needle    See mechanical adjustment  P. 12
    breaks    plate.    “Needle drop .”
      2. Needle is bent or worn.    Change the needle. 
      3. Needle is hitting the hook race.    See mechanical adjustment  P. 13, 14
            “Clearance between needle and 
      hook .”
      4. The fabric moves while the   See mechanical adjustment  P. 11
        needle is piercing it, or the    “Needle swing.”
        needle zigzags while in fabric.
     
      5. Fabric is being pulled too    Guide the fabric gently while
        strongly while sewing.   sewing.