Bernina 990 - Upper Thread Breaks; Upper Thread Indicator Issues; Buttonhole Sewing Problems; Stitch Plate Not Detected

Maintenance
15 Troubleshooting 105
Upper Thread Breaks
Incorrectly threaded.
►
Rethread the upper thread.
Poor quality thread.
►
Use quality thread.
The stitch plate or the hook tip is damaged.
►
Contact your BERNINA dealer to have the damages
repaired.
►
Replace the stitch plate.
The thread is caught in the area of the thread take-up
lever.
►
Slide the cover at the front of the sewing machine
head to the left and remove the cover.
►
Remove the thread remnants.
►
Guide the 4 knobs of the cover into the recesses
provided and push the cover to the right until it
clicks into place.
Upper Thread Indicator fails to respond
The upper thread indicator is not switched on.
►
Switch on the upper thread indicator in the
Settings. [}see page44]
The upper thread indicator is defective.
►
Contact your BERNINA dealer.
Upper Thread Indicator reacts too frequently
Upper thread not threaded correctly.
►
Thread the upper thread correctly. [}see page34]
Upper thread tension too low.
►
Adjust the upper thread tension. [}see page50]
The upper thread indicator is defective.
►
Contact your BERNINA dealer.
Buttonholes are repeatedly not sewn properly
The Buttonhole Foot with Slide#3A is not calibrated
with the machine.
►
Calibrate Buttonhole Foot with Slide#3A. [}see
page47]
Lens on the presser foot is dirty.
►
Clean the lens with a soft, slightly damp cloth.
Stitch Plate not detected
Stitch Plate without sensor.
►
Attach Stitch Plate with sensor.
Disturbance due to magnetic field.
►
Remove magnetic accessories in the area of the
stitch plate.
Sensor on the stitch plate defective.
►
Contact your BERNINA dealer.