Singer S900 Manuel D'instruction page 38

HELPFUL MESSAGES
If an incorrect operation is made, a helpful message will be displayed. When
a helpful message is displayed, fix the problem following the instructions
below.
Check bobbin winder and move it to left.
Buttonhole lever is not lowered or raised.
Lower buttonhole lever when sewing buttonholes.
Raise buttonhole lever when sewing stitch patterns.
Foot control plug is pulled out, while operating foot control.
Push in foot control plug.
Machine is locked up due to thread entangled with bobbin case or rotation
interrupted forcibly.
Turn off power switch and eliminate the problem that caused the machine
to stop.
Reverse/tacking stitch button is pushed, while buttonhole stitch is selected.
Tacking stitch is made automatically after buttonhole stitch is completed.
It is not necessary to push the reverse/tacking stitch button.
Breakage of top thread is detected.
Bobbin winder is in operation.
Move bobbin winder to left when it is not used.
36