5. TROUBLESHOOTING
112
Cause Check Remedy Page
Upper thread feeding Thread take-up amount Loosen the screw to decrease thread take-up
amount so that upper thread does not pull out of
scissors assembly at the sewing start.
101
Needle bar height and
needle bar lift amount
Adjust the needle and hook timing.
1. Adjust the needle bar height to “1” on the gauge.
2. Adjust the needle bar lift amount to “2” on the
gauge.
83
Rotary hook
Thread chips on rotary
hook edge
Remove thread chips.
-
Machine stopping
position
Upper shaft pulley
stopping position
Adjust the needle up sensor position.
103
Lower thread retaining
amount
Adjust the lower thread retaining amount.
96
Lower thread snapping
⋅ Use memory switch No. 02 to retard the work
clamp lifting speed.
⋅ Process the lower thread retainer, lower thread
clamp and lower thread presser plate so that they
do not snap the lower thread.
Instruction
manual
Lower thread
Lower thread clamp
opening timing
Adjust so that the lower thread clamp plate opens
when the feed mechanism moves 6 – 7 mm.
97
Slow speed
Use parameter number 60 to reduce the slow
speed.
Instruction
manual
Sewing start speed
Slow start stitches
Use parameter number 59 to increase the number of
slow start stitches.
Instruction
manual
Bar tack thread
tension
Bar tack thread tension is
too strong.
Make the bar tack tension as weak as possible.
100
Upper thread
breakage
Upper thread breaks. Refer to “5-1. Upper thread breakage”.
104, 105
4000Q
Screw
Increase
Decrease
4003Q
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