Main Motor Does Not Turn - Brother PE770 Service Manual

Failure Investigation for Electronic Parts Main motor does not turn
Is the main motor connector correctly
connected to CN301 of the power
supply unit?
Is the main motor resistance 1.5 – 3.5 Ω?
5 - 8

Main motor does not turn

Does the pulley turn smoothly?
Y
Y
Y
Are the resistance values for the
Stop/Start switch, Needle position
switch and the thread cuttur switch
normal?
• Switch resistance values
Switch depressed ... 1 Ω or less
Switch out ............. ∞
Y
To next page
N
Adjust the assembly of the
upper shaft assy.
N
Connect it properly.
N
Replace the main motor.
N
Replace the SS PCB assy.