Brother PR670E Operation Manual page 221

Symptom
Probable Cause/Remedy
The upper thread breaks.
The needle is not correctly installed.
• Correctly install the needle.
The needle set screw is loose.
• Use the Allen screw driver to tighten the
needle set screw.
The needle is bent or blunt.
• Replace the needle with a new one.
The area around the hole in the needle plate is
damaged.
1 Scratches/Burrs
• Replace the needle plate.
The needle is touching the needle plate.
1 Needle
2 Needle plate hole
3 Needle touching hole
The presser foot is set too high and not correctly
positioned.
The needle hits/touches the presser foot.
The area around the embroidery foot hole is
damaged.
1 Scratches/Burrs
• Replace the presser foot.
Using a specialty thread like a metallic thread.
• Slow down the machine sewing speed.
Symptom
Page Probable Cause/Remedy
The upper thread breaks.
Sliding surface on hook is not smooth. There
p.79
are burns on it.
p.79
p.30
p.79
1 Hook race area
The thread is loose in the hook area.
• Remove the loose thread. If the thread is
tangled in the hook, clean the hook.
*
The play between the hook and the race is too
much.
The hook does not rotate smoothly.
• Remove lint, clean and apply oil.
The space between the hook stopper and the
hook cannot be adjusted.
The upper thread is not threaded correctly.
*
• Pull the upper thread by hand from below the
presser foot, and check that the thread moves
smoothly. If the thread does not move
smoothly, it is not correctly threaded.
*
Un-thread the machine and
re-thread the machine.
Make sure the thread is correctly positioned
in the needle bar thread guide.
Upper thread is not positioned in upper or
middle thread guide.
• Make sure thread passes completely under
upper and middle thread guide.
* There are knots or tangles in the thread.
• Remove any knots or tangles.
The upper thread tension is too high.
• Decrease the upper thread tension.
The lower thread tension is incorrect.
The thread does not roll out of the bobbin case
smoothly.
• Adjust the lower thread tension.
The bobbin case is damaged.
p.116
• Replace the bobbin case with a new one.
APPENDIX
Page
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p.210
*
p.210
p.214
*
p.50
7
p.50
–
p.103
p.102
p.30
219