Brother b831 - Stitches Skip

TROUBLESHOOTING GUIDE
Troub e
Upper thread
breaks.
Lower thread
breaks.
Uneven stitches.
Stitches skip.
•
•
I
Needle bent, needle lip
crushed.
Needle incorrectly install
ed.
Wrong threading.
Upper thread tension loo
tight.
Wrong clearances between
rotary hook and bobbin case
oper^er.
Wrong needle and rotary
hook timing.
Wrong threading.
Lower thread tension too
tight.
Bobbin stained with oil or
lint.
Needle bent, needle tip
crushed.
Presser foot pressure too
small.
Wrong feed dog height.
Wrong upper feed timing.
Needle bent, needle tip
crushed.
Needle incorrectly install
ed.
Wrong threading.
Presser foot pressure too
small.
Wrong needle and rotary
hook timing.
Wrong upper feed timing.
Check
Needle direction.
Threading.
Upper thread tension.
Threading
Intensity of lower thread
tension regulator screw.
Presser foot pressure
Feed dog height
Needle direction and
height.
Threading.
Presser fool pressure.
Remedy
Replace faulty needle.
Install needles in correct
direction.
See the section for upper
threading.
See the section for thread
tension.
See the section for needle and
rotary hook timing ad{ustment.
See the section for needle and
rotary hook timing adiustment.
See the section for lower
threading.
Ad|ust to proper tension.
Remove lint and oil
thoroughly.
Replace faulty needle
See the section for presser
foot adjustment.
See the section for feed
dog height adjustment.
See the section for vibrating
presser foot and lifting presser
fool and needle timing adjust
ment.
Replace faulty needle.
See the section for install
ing the needle.
See the section for upper
threading.
See the section for presser
foot adjustment.
See the section for needle and
rotary hook timing adjustment.
See the section for vibrating
presser foot and lifting presser
foot and needle timing adjust
ment.