Main Motor Does Not Turn - Brother NV4000D Service Manual

Failure Investigation for Electronic Parts Main motor does not turn
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Main motor does not turn

Does the pulley turn easily?
Y
Is the main motor connector
correctly connected to the power
PCB assembly (CN301)?
Y
Is the harness attached to the power
PCB assembly correctly connected
to the main PCB assembly (CN13)?
Y
Is the main motor resistance 0.5-2.5Ω?
Y
Is the resistance for the start / stop
switch, reverse switch, raise needle
switch, thread cut switch, presser
foot lifter switch, and thread switch
normal?
Switch resistance values
When switch is pressed : 1Ω or less
When switch is not pressed : ∞
Y
To next page
N
Adjust the upper shaft
assembly
N
Reconnect it correctly
N
Reconnect it correctly
N
Replace the main motor
N
Replace the SS PCB assembly (D6)
or thread switch PCB assembly.