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Attachment
12.2 Troubleshooting
Fault
Uneven stitch formation
Uneven stitch formation
Skipped stitches
Faulty stitching
176
Cause
Upper thread too tight or too
loose.
Needle blunt or bent.
Poor quality needle.
Poor quality thread.
Incorrect needle/thread
combination.
Incorrectly threaded.
The fabric has been pulled.
The incorrect bobbin cased is
used.
Incorrect needle.
Needle blunt or bent.
Poor quality needle.
The needle is incorrectly inserted.
Incorrect needle point.
Thread remnants between the
thread tension discs.
Incorrectly threaded.
Thread remnants below the
bobbin case spring.
035964.50.04_2014-08_Manual_B790_EN
Repair
> Adjust upper thread tension.
> Replace the needle, make sure that a new BERNINA
quality needle is used.
> Use a new BERNINA quality needle.
> Use quality thread.
> Match the needle with the thread size.
> Rethread.
> Feed the fabric evenly.
> Use the supplied bobbin case with triangles.
> Use the needle system 130/705H.
> Replace the needle.
> Use a new BERNINA quality needle.
> Insert the needle with the flat side to the back as far up
as it will go and tighten the screw.
> Match the needle point to the texture of the material.
> Fold a piece of thin material and slide the folded edge
(not the raw edges) between the thread tension discs.
> Rethread.
> Remove the thread remnants under the spring.
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