Baby Lock BLMY Service Manual page 195

Failure Investigation for Electronic Parts Pulse motors do not return to starting point
When the power is turned ON, the pulse motors do not return to the
starting point.
• Needle up Z pulse motor return to starting point
• Needle down F pulse motor and S pulse motor returns to starting point
• Regardless of needle position AT&C pulse motor return to starting position
5 - 4
Is the resistance between the 1 & 2
pins and 3 & 4 pins on the pulse
motor connectors 4 – 6 Ω?
Y
Regardless of needle position this
pulse motor returns to the starting point
N
Is the voltage between pins 5 & 4 of
CN14 on the main NF3D PCB assy. 26 V
DC?
Y
Replace main NF3D PCB assy.
N
Replace pulse motor
Y
Replace NP F2 PCB assy.
N
Replace power supply F