Troubleshooting; Upper Thread Breakage - Brother HE-800C Instruction Manual

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.
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
Needle
Threading
Thread path
Thread tension
Thread take-up spring
Check
Needle facing
Needle installation height
Bent needle
Blunt needle tip or burr
Needle and thread
Upper thread threading
Lower thread threading
Flaw or abrasion on the
thread path
Flaw on the rotary hook tip
and rotary hook edge
Flaw on the rotary hook
holder
Zigzag thread upper thread
tension
Bar tack thread upper
thread tension
Thread take-up spring
tension and height
CAUTION
Remedy
As viewed from the direction of the face plate, attach
the needle so that the groove of the needle faces
frontward.
Insert the end of the needle shank so that it touches the
top edge of the needle hole of the needle bar.
Replace needle.
Replace needle.
Replace needle that fits the thread.
Thread the upper thread correctly.
Thread the lower thread correctly.
Polish with buff or replace the part.
Especially, pay attention to finishing around needle
plate hole.
Needle plate hole
Polish with buff or replace the part.
Polish with buff or replace the part.
Adjust the upper thread tension appropriately.
Adjust the upper thread tension while checking
stitches. (The stitches on top are the upper thread and
the stitches underneath are the bobbin thread.)
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.
HE-800C
11. TROUBLESHOOTING
3996Q
Check flaw here
Adjust the rotary hook
overlap amount.
3997Q
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