Skipped Stitches; Uneven Seams (1) - Brother KE-430HX Service Manual

13. TROUBLESHOOTING
13-2

. Skipped stitches

Items with a "*" in the "Page" column should only be handled by a qualified technician.
Cause
Thread tension
Thread take-up
spring
Needle
Needle bar play
Hook
Needle plate
Feed plate
Work clamp
13-3 . Uneven seams (1) ...... Incorrect thread tightness
Items with a "*" in the "Page" column should only be handled by a qualified technician.
Cause
Upper thread
Thread take-up
spring
Lower thread
173
Check
Upper thread tension
Thread take-up spring
tension and height
Needle facing
Needle installation height
Bent needle
Blunt needle tip or burr
Needle count
Vertical and longitudinal
needle bar play
Blunt shuttle hook tip
Needle bar lift amount
Driver needle guard
Gap between needle and the
tip of the shuttle hook
Relation between material
and needle plate
Relation between material
and feed plate
Relation between material
and work clamp
Check
Upper thread tension
Thread take-up spring
tension
Lower thread tension
KE-430HX/KE-430HS, BE-438HX/BE-438HS
Remedy
Adjust the upper thread tension appropriately.
Loosen the thread take-up spring tension or lower the
height to such a degree that does not cause double
hooking.
Attach the needle so that the long groove on the
needle is at the front.
Insert the end of the needle shank so that it touches
the top edge of the needle hole of the needle bar.
Replace needle.
Replace needle.
Use a needle with a count that matches the thread and
material or one with a smaller size.
Reduce the needle bar play, or replace the parts.
Polish with buff or replace the part.
* Use the KE-430H/BE-438H hook.
Adjust the needle bar lift amount.
Adjust the needle and hook timing
Adjust the driver so that the needle contact pressure is
not too great.
Adjust the gap between the needle and the tip of the
shuttle hook to 0.01 - 0.08 mm. (Adjust to as large as
possible without causing skipped stitches to occur.)
* Move the needle bar back and forth with your finger,
and check that the tip of the shuttle hook does not
strike the needle.
Use a needle plate that matches the material.
Use a feed plate that matches the material.
Use a work clamp that matches the material.
Remedy
Adjust the upper thread tension appropriately.
・ If the upper thread trailing length varies considerably,
increase the thread take-up spring tension.
・ If the upper thread trailing length is short, decrease
the thread take-up spring tension.
・ If the thread take-up spring operation is unstable,
increase the thread take-up tension, and also
increase the stroke.
Adjust the lower thread tension appropriately.
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Instruction
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134
Instruction
manual
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Instruction
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132,
Instruction
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