Pulse Motors Do Not Return To Starting Position - Brother PE770 Service Manual

Failure Investigation for Electronic Parts Pulse motors do not return to starting position
When the power is turned ON, the pulse motors do not return to the
starting position.
• Regardless of needle position, the AT&C pulse motor return to starting position.
Is the resistance between the 1 & 2
pins and 3 & 4 pins on the pulse
motor connector 4 – 6 Ω?
Is the FFC connected correctly
between the main PCB (CN5) and
the motor PCB (CN1)? Are both
connector locks applied correctly?
Is the FFC connecting the main PCB
(CN5) to the motor PCB (CN1) free
from breakage?
Is the voltage between pins 5 & 4 of
CN19 on the motor PCB assy. 26 V DC?
Y
Y
N
Y
Replace the main PCB assy.,
or
Replace the motor PCB assy.
N
Replace the pulse motor.
N
Connect it properly.
Y
Replace the FFC.
N
Replace the power supply unit.
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