Errors and Faults
95
2022-08 EN 5020077.40A.04
12 Errors and Faults
12.1 Troubleshooting
Fault
Cause
Repair
Uneven Stitch Formation
Upper thread too tight or too
loose.
> Adjust the upper thread tension.
Needle blunt or bent.
> Replace the needle, make sure that a new BERNINA
quality needle is used.
Poor quality needle.
> Use a new BERNINA quality needle.
Poor quality thread.
> Use quality thread.
Incorrect needle/thread
combination.
> Match the needle with the thread size.
Incorrectly threaded.
> Rethread.
The fabric has been pulled.
> Feed the fabric evenly.
Dust or thread remnants under
the tension spring of the bobbin
case.
> Remove any dust or thread remnants from under the
tension spring of the bobbin case.
Skipped Stitches
Incorrect needle.
> Use the needle system 130/705H.
Needle blunt or bent.
> Replace the needle.
Poor quality needle.
> Use a new BERNINA quality needle.
The needle is incorrectly inserted.
> Insert the needle with the flat side to the back as far up
as it will go into the needle holder and tighten the
screw.
Incorrect needle point.
> Match the needle point to the texture of the material.
Faulty Stitching
Thread remnants between the
thread tension discs.
> Fold a piece of thin material and slide the folded edge
(not the raw edges) between the thread tension discs.
Incorrectly threaded.
> Rethread.
Thread is caught in the hook.
> Remove the upper thread and the bobbin case, turn the
handwheel backwards and forwards by hand and
remove the thread remnants.
Incorrect needle/thread
combination.
> Check the needle/thread combination.
Summary of Contents for b77
Page 1: ...User Manual...
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