Check for the following matters.

• Probable cause

  Thread tensions are not adjusted properly.

   

  Remedy

  Adjust the thread tension.

   

  Refer to the instructions to learn the adjustment of thread tension.

  Adjusting the thread tension dials

  Thread tension adjustment

• Probable cause

  Improper threading.

   

  Remedy

  Thread correctly.

   

  Refer to the instructions to learn threading.

  Threading the loopers

  Threading the needles