Trouble Shooting; Skipped Stitches; Needle Breaks - Bernina Artista 640 User Manual

104 Trouble Shooting

Trouble Shooting
In most cases you will be able to identify and remedy faults by checking the following.
Check whether:
• the upper and lower threads are threaded correctly
• the needle is inserted correctly with the flat side to the back
• the needle size is correct – check the needle/thread table page 17
• the sewing computer is clean – brush out any thread lint
• the hook race is clean
• any threads are trapped between the tension discs or under the bobbin case spring
Upper Thread Breaks
Possible Faults:
• The upper thread tension is too tight.
• The needles are of a poor quality. Ideally
needles should be purchased from your
BERNINA dealer.
• The needle has been inserted incorrectly.
The flat side of the shank must be to the
back.
• The needle is bent or blunt.
• Poor quality, knotted or dried out thread
has been used.
Possible Solutions:
• Use the correct spool disc.
• Stitch plate or hook tip damaged. Take
your sewing computer to your BERNINA
dealer.
Removing Trapped Thread
If the lower thread breaks and the thread is
trapped in the area of the take-up lever,
proceed as follows:
• power switch to «0» (off)
• remove the screw on the head frame with
the angular Torx key
• pull head frame to the left
• remove remnants of thread
• attach head frame and tighten screw
Lower Thread Breaks
• The lower thread tension is too tight.
• The bobbin is jamming in the bobbin case:
• Remove and replace the bobbin.
• The hole in the stitch plate has been
damaged by the needle:
• This must be repolished by an authorized
BERNINA technician.
• The needle is blunt or bent.
Calibration of the Display
To open the calibration screen directly,
proceed as follows:
• press both needle position buttons on the
body simultaneously and keep them
pressed
• turn on the sewing and embroidery
computer
• as soon as the calibration screen is opened,
release the two buttons
• Calibration of the Display see page 96

Skipped Stitches

• Wrong needles used:
• Use only 130/705H system.
• The needle is blunt, bent or incorrectly
inserted:
• Push right to the top when inserting.
• Needle is of inferior quality or badly
polished.
• The needle point does not suit the fabric
being sewn. If necessary use a ball point
for knitted fabrics and cutting point for
hard leather.

Needle Breaks

• Needle clamp screw loose.
• Fabric taken out in front of instead of
behind the presser foot.
• When sewing over a thick area, the fabric
was pushed with the needle still in the
fabric; use Jeans foot No. 8 (optional
accessory).
• Poor quality thread, unevenly wound or
knotted.
• Information on needles see page 17
Faulty Stitching
• Remnants of thread between the tension
discs:
• pull folded, thin fabric (do not use
fabric edge) between the tension
discs and clean them by moving the
fabric forwards and backwards on
the left and right side of the thread
tension
• Remnants of thread under the bobbin case
spring.
• Incorrect threading. Check upper and
lower threads.
• Use the correct spool disc.
• clean and oil the hook race area
Cannot Sew Thick Fabric
• Needle/thread combination is not correct
(the thread is too thick for the inserted
needle).
• Use hight compensating tool, when sewing
over a thick seam.
Sewing Computer Fails to
Run or Runs Slowly
• Plug not properly inserted.
• Power switch in off position («0»).
• Sewing computer has been standing in a
cold room.
• restart sewing computer
Defective Sewing Light
• Please note that the CFL-sewing light must
be replaced by an authorized BERNINA
technician.
Upper Thread Indicator
Sensor
• not activated in the Setup Program
Lower Thread Indicator
Sensor
• bobbin cover is not closed
• not activated in the Setup Program
• remove any thread lint and remnants from
the bobbin case
Update error
If the update process is at a still stand (hour
glass remains) proceed as follows:
1. Remove the USB stick and turn off the
Sewing/Embroidery computer
2. Turn on the Sewing/Embroidery computer
and proceed with the update as indicated
by a message on the display