Pulse Motors Do Not Return To Starting Position - Brother XR9000 Service Manual

Failure Investigation
for Electronic Parts
When the power is turned ON, the pulse motors do not return to the starting
position.
• When needle is up : Z pulse motor returns to it's starting position.
• When needle is down : F pulse motor returns to it's starting position.
When the Z pulse motor does not
return to starting point, is the resistance
between the pins 1 & 4, 2 & 3, 3 & 2
and 4 & 1 at the ZPM lead wire assy.
1Ω or less?
When the F pulse motor does not
return to starting point, is the resistance
between the pins 1 & 4, 2 & 3, 3 & 2
and 4 & 1 at the FPM lead wire assy.
1Ω or less?
5 - 4

Pulse motors do not return to starting position

Is the resistance between the 1 & 2
pins and 3 & 4 pins on the pulse
motor connectors 6.7-7.7Ω?
Y
Y
Y
Replace the main PCB assy.
N
Replace the pulse motor.
N
Replace the ZPM lead wire assy.
N
Replace the FPM lead wire assy.