Uneven Seams; Seam Lifts Up At The Sewing Start; Uneven Sewing Pitch At The Sewing Start; Poor Rounding Of Seam - Brother HE-800A Instruction Manual

１６-５. Uneven seams (3) ......Seam lifts up at the sewing start
Seam lifts up and does not tighten at the sewing start
Cause
Upper thread
scissors
Upper thread feeding
１６-６. Uneven seams (4) ...... Uneven sewing pitch at the sewing start
Bird's nests form at the sewing start, and after 5 – 6 mm the sewing pitch suddenly increases
Cause
Lower thread clamp
１６-７. Uneven seams (5)......Poor rounding of seam
Cause
Thread tension
Threading
Stitch patterns
Tension release
１６-８. Uneven seams (6) ...... Around rear tack or front tack
Cause
Tension release
Threading
Zigzag thread
tension
Upper thread
scissors
Check
Upper thread scissors
gradual opening timing
Upper thread scissors
operation
Thread take-up amount
Check
Lower thread clamp
opening timing
Check
Zigzag thread upper
thread tension
Zigzag tension disc
opening
Lower thread tension
Upper thread threading
Lower thread threading
Purl stitch, whip stitch
Tension release timing
Check
Tension release timing
Upper thread threading
Lower thread threading
Zigzag tension disc
opening
Upper thread scissors
operation
Remedy
Adjust the timing so that the upper thread scissors
gradually start opening when the feed mechanism
moves about 1.5 - 2.5 mm.
Apply grease to the inclined face of the opening
cam.
Loosen the screw to decrease thread take-up
amount so that upper thread does not pull out of
scissors assembly at the sewing start.
Increase
Decrease
Remedy
Advance the timing at which the lower thread clamp
starts to open.
Remedy
Adjust the upper thread tension appropriately.
Check the opening of the zigzag tension discs.
Replace the tension release solenoid.
Adjust the lower thread tension appropriately.
Thread the upper thread correctly.
Thread the lower thread correctly.
Set using parameter number 11.
Use parameter numbers 63 to 66 to change the
tension release on and off timing.
Remedy
Use parameter numbers 63 to 66 to change the
tension release on and off timing.
Thread the upper thread correctly.
Thread the lower thread correctly.
Adjust the tension disc opening amount.
Check the opening of the zigzag tension discs.
Replace the tension release solenoid.
Apply grease to the inclined face of the opening
cam.
HE-800A
16. TROUBLESHOOTING
Page
76
76
Screw
-
4000Q
Page
77
Page
62
62
61
58
60
37
44
Page
44
58
60
62
76
96