Main Motor Rotation Abnormal - Brother PE770 Service Manual

Failure Investigation for Electronic Parts Main motor rotation abnormal
• The rotation of the main motor is unstable.
• The rotation speed does not reach maximum.
When the upper shaft pulley is slowly
turned by hand, does the voltage
between pins 6 & 1, pins 4 &1 and
pins 5 & 1 of CN7 on the motor PCB
assy. vary 0 – 5 V DC?
5 - 10
or
Y
Y
Replace the main PCB assy.
N
Replace the NP PCB assy.