JUKI MF-7800D Series, Engineer'S Manual

Page: 158 / 165

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5-10) Irregular stitches 10-A) Throat plate A-1) Incorrect position Polish correctly.
(Left, Middle, Right)
10-B) Spreader adjustment B-1) Stroke of spreader is too large. Refer to the standard adjustment figures.
10-C) Looper C-1) Worn out looper’s pointed end Replace the looper when modified or its is shape
and incorrect polishing changed too much.
10-D) Top covering thread D-1) Drawing-in amount of top Refer to the standard adjustment figures.
take-up covering thread is too much.
10-E) Needle thread tension E-1) Needle thread tension is too weak. Increase tension.
10-F) Threading F-1) Incorrect threading Refer to threading diagram.
10-G) Top covering thread G-1) Thread tension is too weak. Increase tension.
tension
10-H) Looper thread cam H-1) Drawing-in amount of looper Reduce drawing-in amount of thread.
thread guide position thread is too much.
5-11) Ill-tensed seam 11-A) Throat plate A-1) Incorrect polishing. Too long Correct or replace part.
stitch tongue
11-B) Needle B-1) Worn out needle point, needle Replace needle with new one,
bend, wrong needle Use UY128GAS.
11-C) Looper C-1) Worn out looper’s pointed end, Replace the looper when modified or its shape
incorrect polishing is changed too much.
11-D) Needle height D-1) Needle bar position is too low. Refer to the standard adjustment figures.
11-E) Threading E-1) Incorrect threading Refer to threading diagram.
11-F) Needle thread tension F-1) Tension is too weak. Increase tension.
11-G) Needle thread guide rod G-1) Either the position of thread Refer to the standard adjustment figures.
guide is too low or too high.
11-H) Looper thread tension H-1) Tension is too strong. Reduce tension.
11-I) Looper thread cam I-1) Drawing-in amount of looper Increase drawing-in amount of thread.
thread guide position thread is too little.
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Trouble (1) Trouble (2) Cause (1) Cause (2) Corrective measures