HE-800B
11. TROUBLESHOOTING
77
11. TROUBLESHOOTING
• Please check the following points before calling for repairs or service.
• If the following remedies do not fix the problem, turn off the power switch and consult a qualified technician or the place of
purchase.
CAUTION
Turn off the power switch and disconnect the power cord before carrying out troubleshooting, otherwise the
machine may operate if the treadle is depressed by mistake, which could result in injury.
11-1. Upper thread breakage
Items with a “*” in the “Page” column should only be handled by a qualified technician.
Cause Check
Remedy
Page
Needle facing
As viewed from the direction of the face plate, attach
the needle so that the groove of the needle faces
frontward.
21
Needle installation height
Insert the end of the needle shank so that it touches
the top edge of the needle hole of the needle bar.
21
Bent needle
Replace needle.
21
Blunt needle tip or burr
Replace needle.
21
Needle
Needle and thread
Replace needle that fits the thread.
–
Upper thread threading
Thread the upper thread correctly.
22
Threading
Lower thread threading
Thread the lower thread correctly.
25
Flaw or abrasion on the
thread path
Polish with buff or replace the part.
Especially, pay attention to finishing around needle
plate hole.
*
Flaw on the rotary hook tip
and rotary hook edge
Polish with buff or replace the part.
*
Thread path
Flaw on the rotary hook
holder
Polish with buff or replace the part.
*
Zigzag thread upper thread
tension
Adjust the upper thread tension appropriately.
26, 27
Thread tension
Bar tack thread upper
thread tension
Adjust the upper thread tension while checking
stitches. (The stitches on top are the upper thread and
the stitches underneath are the bobbin thread.)
26, 27
Thread take-up spring Thread take-up spring
tension and height
Loosen the thread take-up spring tension or lower the
height to such a degree that does not cause double
hooking. Adjust it while checking bar tacking stitches.
28
(Continued on next page)
3996Q
3997Q
Needle plate hole
Adjust the rotary hook
overlap amount.
Check flaw here