Unraveling Of Thread Trimmed By Upper Thread Trimmer Assembly - Brother HE-800B Service Manual

11-14. Unraveling of thread trimmed by upper thread trimmer assembly

Items with a "*" in the "Page" column should only be handled by a qualified technician.
Cause
Upper thread trimmer
assembly
Tension release
timing
Check
Installation position
upper thread trimmer
assembly
Burr on tips of upper thread
trimmer M and upper
thread trimmer U.
Opening amount of zigzag
tension discs and bar tack
tension discs (particularly
zigzag tension discs)
of Adjust the installation position of upper thread trimmer
assembly by moving the setting plate assembly.
・ Upper thread
adjustment
・ Upper thread trimmer cutting depth adjustment
Polish with buff or replace the part.
・ Adjust the zigzag tension discs by moving the
tension stud bracket in and out.
・ Adjust the bar tack tension discs opening amount to
0.5 - 1.0 mm by removing the top cover and moving
the tension release cam.
Zigzag tension
HE-800B
11. TROUBLESHOOTING
Remedy
trimmer longitudinal
Check burr on upper
side here
Check burr here
Tack tension
0.5 - 1 mm
Page
position
98, 99
4005Q
–
4009Q
108
4008Q
158