HE-800B
11. TROUBLESHOOTING
84
11-12. Uneven seams (10) …… All stitches
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check
Remedy
Page
Upper thread threading
Thread the upper thread correctly.
22
Threading
Lower thread threading
Thread the lower thread correctly.
25
Thread path
Flaw or abrasion on the
thread path
Polish with buff or replace the part.
Especially, pay attention to finishing around needle
plate hole.
*
Needle installation
Insert needle fully into needle bar.
21
Needle
Needle size
Replace needle with thicker one.
*
Thread chips or dust
Rotary hook rim
Rotary hook edge
Around needle plate hole
Remove thread chips or dust.
62, 63
Upper thread tension
Increase upper thread tension while checking stitches.
26, 27
Upper thread
Thread and needle
Replace needle with one that fits for the thread.
–
Flaw on the rotary hook
holder
Polish with buff or replace the part.
*
Rotary hook holder
Rotary hook holder and
inner rotary hook overlap
amount
Adjust the rotary hook holder and inner rotary hook
overlap amount.
66*
Rotary hook
Rotary hook lubrication
Decrease the quantity of lubrication oil.
* Note that if you reduce the amount of oil too much,
thread breakages may occur.
16*
Bobbin thread tension
Use the tension nut to adjust the lower thread winding
tension.
24
Bobbin winder tension
bracket
Uneven bobbin winding
Move bobbin winder tension bracket up and down to
adjust.
24
Lower thread
Lower thread tension
Adjust the lower thread tension.
26
Bobbin case
Damaged outside of
bobbin case and bent
bobbin holder spring, etc.
Polish with buff or replace the part.
* Use the HE-800B bobbin case.
*
Stitch patterns
Purl stitch, whip stitch
Set using parameter number 53.
40
3996Q
3997Q
Needle plate hole
Adjust the rotary hook
overlap amount.
Check flaw here