Brother HE-800C - Uneven Seams; Uneven Sewing Pitch at the Sewing Start; Poor Rounding of Seam; Around Rear Tack or Front Tack

HE-800C
11. TROUBLESHOOTING
83
11-6. 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
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check Remedy Page
Lower thread clamp Lower thread clamp
opening timing
Advance the timing at which the lower thread clamp
starts to open.
71*
11-7. Uneven seams (5)……Poor rounding of seam
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check Remedy Page
Thread tension Zigzag thread upper thread
tension
Adjust the upper thread tension appropriately.
26, 27
Zigzag tension disc
opening
・Check the opening of the zigzag tension discs.
・Replace the tension release solenoid.
*
Lower thread tension Adjust the lower thread tension appropriately. 26
Threading Upper thread threading Thread the upper thread correctly. 22
Lower thread threading Thread the lower thread correctly. 25
Stitch patterns Purl stitch, whip stitch Set using parameter number 53. 40
Tension release Tension release timing Use parameter numbers 54 to 57 to set the timing for
changing the thread tension.
40
11-8. Uneven seams (6) …… Around rear tack or front tack
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check Remedy Page
Tension release Tension release timing Use parameter numbers 54 to 57 to set the timing for
changing the thread tension.
40
Threading Upper thread threading Thread the upper thread correctly. 22
Lower thread threading Thread the lower thread correctly. 25
Zigzag thread tension Zigzag tension disc
opening
・Adjust the tension disc opening amount.
・Check the opening of the zigzag tension discs.
・Replace the tension release solenoid.
*
Upper thread trimmer Upper thread trimmer
operation
Apply grease to the inclined face of the opening cam.
70*
11-9. Uneven seams (7) …… Loose thread end at end backtack
Cause Check Remedy Page
Backtack shape Checking the number of
end backtack stitches
Checking the end backtack
width
Adjust the setting values for parameter numbers 51
and 52.
39