Singer Quantum Stylist 9960 Service Manual page 24

Bobbin winder switch sensor (W)
Is located in the bobbin winding unit
Check
Move the bobbin winder spindle left or right and check this switch.
W: Bobbin Winder Switch
1=Bobbin winder spindle is in right position
0=Spindle is in left position
Bobbin winding stop (w)
Is located in the bobbin winding unit
Check
1. Move the bobbin winder spindle to winding position.
2. Then move the bobbin winder stopper to the right to check switch
w: Bobbin Winding Stop Switch
1=Bobbin winder stop is not pushed (Bobbin winding is not full)
0=Bobbin winder stop is pushed to the right (Bobbin winding is full.)
Presser foot sensor switch (O)
Is located on the back of the zigzag step motor unit.
Check
Lower or lift the presser foot lifter and check the response of this switch.
O: Presser foot switch
1=Presser foot is lowered
0=Presser foot is lifted
Upper Thread sensor (Y)
Is located at the thread take up spring
Check
To check the response of this sensor -
Thread the upper thread and pull it up or slack it off to move the thread take up spring
Y: Upper thread sensor
1= threaded
0= not threaded
24 Singer Quantum Stylist
TM
9960