Instruction Manual

25.Trouble shooting
1.Thread breakage
(thread wear and
tear)
2.Skip stitch
3.Loose stitch
Tr ou bl e
Ca us es
So lu ti on
① Threading course, n eedle tip, h o ok blade
tip or thread passing g r oove on the th r oat
plate is rough.
② Too large needle thre a d tension.
③ Too big clearance of in n er hook guid e .
④ collision between n e edle and hoo k g uide
tip.
⑤ Too small needle thre a d tension.
⑥ TOOlarge or too small s t roke threa d t ake
-up spring tension
⑦ Not timing between ne e dle and hook .
① Too big cle ar ance between ne edle and
the tip of in ne r hook blade.
② Not timing be tween needle an d hook.
③ Too small pre ssure on the oute r presser
foot.
④ the height of n eedle bar is not en ough.
⑤ No effect of ne edle guard plat e.
⑥ Wrong nee dl e size.
⑦ Wrong nee dl e threading.
⑧ Rotary ho ok i s scraped.
① The thread passing parts are not smooth.
② the bobbin cannot rotate smoothly.
③ Too big clearance of inner hook guide.
④ Too weak tension of bobbin thread.
⑤ too tighten when winding bobbin thread.
⑥ bobbing thread doesn't pass the thread
tension spring on the bobbin case
Get rid of the burr on the hoo k blade tip
and polish the thread pa ssing groov e on
the throat plate with fi ne emery clot h.
Adjust the needle thre ad to proper te nsion.
Decrease the clearan ce,refer to 21.
Adjusting the inner ho ok guide.
Rdfer to 19. Adjusting t he needle and
hook.
Adjust the needle thre ad to proper te nsion.
Decrease the tension o f thread take -up
Spring and increase th e spring stro ke.
Refer to 19. Adjusting t he needle and h ool.
Refer to 19.Adjustin g t he needle an d h ook.
Refer to 19.Adjustin g t he needle an d h ook.
Tighten the pressure s c rew.
Refer to 19.Adjustin g t he needle an d h ook.
Refer to 20.Adjustin g t he needle gu a rd
plate.
Change a proper needle .
Refer to 12.Threadin g t he needle th r ead.
Get rid of the burr on the hoo k g uide tip
with fine emery cloth.
Polish them with fine emery cloth.
Reset the bobbin and rotary hook.
Refer to 21. Adjusting the inner hook
guide.
Adjust the bobbin thread tension properly.
Decrease the tension when winding.
Threading the bobbin thread correctly.