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HE-800A
16. TROUBLESHOOTING
95
Cause Check Remedy Page
Lower thread tension Adjust the lower thread tension appropriately. 61
Bobbin holder spring Add tension to the bobbin holder spring.
.
-
Lower thread retainer
position
Adjust the lower thread retainer position.
* Adjust lower thread retainer so that a 35 – 40 mm
thread leader is left after trimming.
-
Bobbin presser position Adjust the bobbin presser position. 77
Bobbin insertion Insert the bobbin correctly. 60
Lower thread (bobbin
slip)
Work clamp lifting speed Reduce the setting for memory switch No. 02. 79
ውዒ
-
ዐ
. Uneven seams (2) …… Lower thread is lifted up at the sewing start
The end of the lower thread protrudes above the seam at the sewing start
Cause Check Remedy Page
Lower thread
retainer
Lower thread retaining
amount
Adjust the lower thread retaining amount.
-
Lower thread clamp
opening timing
Adjust so that the lower thread clamp plate opens
when the feed mechanism moves 6 – 7 mm.
77
Lower thread clamp
Lower thread clamping
force
If the lower thread clamp and lower thread presser
are bent, replace them.
Check that the screws are tightened.
-
4001Q
Add tension to the spring by the same
amount that the bobbin tab is projecting
Make a gap
4003Q
4002Q
35 - 40mm
3999Q
Lower thread
clamp
Screw