Pulse Motors Do Not Return To Starting Point - Brother NV-10A Service Manual

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 returns to starting point
Is the connector of the Z pulse motor
correctly connected to CN8 of the main
PCB assy.?
Is the connector of the F pulse motor
correctly connected to CN10 of the main
PCB assy.?
Is the resistance between the 1 & 2 pins
and 3 & 4 pins on the pulse motor
connectors 6.7 – 7.7 Ω?
Is the voltage between pins 3 & 4 of CN5
on the main PCB assy. 30 V DC?
Regardless of needle position this
pulse motor returns to the starting point
5 - 4
Y
Y
Y
Y
Y
Attach the main PCB assy. to
the correct position of the
shutter cover
N
Reconnect it correctly
N
Reconnect it correctly
N
Replace the pulse motor
N
Replace the power supply
PCB assy.
N
Replace the main PCB assy.