Bernina 720 User Manual page 152

Fault
Upper thread breaks
Lower thread breaks
Needle breaks
Display is inactive
Stitch width not adjustable
Cause
Incorrect needle/thread
combination.
Upper thread is too tight.
Incorrectly threaded.
Poor quality thread.
The stitch plate or the hook tip is
damaged.
The thread is caught in the area
of the thread take-up lever.
1
The bobbin case is damaged.
The stitch hole in the stitch plate
is damaged.
Needle blunt or bent.
The needle is incorrectly inserted.
The fabric has been pulled.
Thick fabric has been pushed.
Knotted thread.
Incorrect calibrating data.
The eco-function is active.
The selected needle and stitch
plate cannot be used in
combination.
036045.50.04_2014-10_Manual_B720_EN
Repair
> Match the needle with the thread size.
> Reduce the upper thread tension.
> Rethread.
> Use quality thread.
> Contact the nearest specialized BERNINA dealer to have
the damages repaired.
> Replace the stitch plate.
> Remove the screw (1) on the headframe with the
angular Torx wrench.
> Pull the headframe at the bottom slighty forward.
> Flip the headframe upwards a bit and remove it.
> Remove the thread remnants.
> Attach the headframe and tighten the screw.
> Replace the bobbin case.
> Contact the nearest specialized BERNINA dealer to have
the damages repaired.
> Replace the stitch plate.
> Replace the needle.
> Insert the needle with the flat side to the back as far up
as it will go and tighten the screw.
> Feed the fabric evenly.
> Use the correct presser foot for thick material e.g. Jeans
foot No. 8.
> Use the height compensating tool when sewing over a
thick seam.
> Use quality thread.
> Switch the machine off.
> Switch the machine on and at the same time push
button «Needle left/right» and keep it pressed.
> Re-calibrate the Display.
> Touch the icon «eco».
> Replace the needle.
> Replace the stitch plate.
Attachment
153