Bernina 740 Manual page 119

Attachment
Malfunction
Upper thread breaks
Lower thread breaks
Needle breaks
Display is inactive
Stitch width not adjustable
120
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.
036044.50.04_2014-09_Manual_740_EN
Repair
> Match the needle with the thread size.
> Reduce the upper thread tension.
> Rethread.
> Use quality thread.
> Contact your BERNINA specialized dealer to eleminate
the damages.
> Change the stitch plate.
> Remove the screw (1) at the cover with the Torx Allen
wrench.
> Pull the cover carefully to the front.
> Flip the cover slightly upwards to remove it.
> Remove the thread remnants.
> Attach the cover and tighten the screw.
> Replace the bobbin case.
> Contact your BERNINA specialized dealer to eleminate
the damage.
> Change the stitch plate.
> Change the needle.
> Insert the needle with the flat side to the back as far it
will go and tighten the screw.
> Feed the fabric evenly.
> Use the appropriate presser foot, i. e. the Jeans foot No.
8, for thick material.
> Use the height compensation tool for thick seams.
> Use quality thread.
> Switch the machine off.
> Switch the machine on and at the same time push the
button «Needle left/right» and keep pressed.
> Calibrate the display again.
> Touch the icon «eco».
> Change the needle.
> Change the stitch plate.