HE-800B
11. TROUBLESHOOTING
87
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 Check
Remedy
Page
Installation position of
upper thread trimmer
assembly
Adjust the installation position of upper thread trimmer
assembly by moving the setting plate assembly.
・
Upper thread trimmer longitudinal position
adjustment
・
Upper thread trimmer cutting depth adjustment
*
Upper thread trimmer
assembly
Burr on tips of upper thread
trimmer M and upper
thread trimmer U.
Polish with buff or replace the part.
*
Tension release
timing
Opening amount of zigzag
tension discs and bar tack
tension discs (particularly
zigzag tension discs)
・
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.
*
4009Q
4005Q
Check burr on upper
side here
Check burr here
4008Q
Tack tension
0.5 - 1 mm
Zigzag tension