Thread Is Not Cut Normally - Brother PR600 Service Manual

Failure Investigation for Electronic Parts Thread is not cut normally.
Is the thread cutter sensor's lead
properly connected to CN11 on the
main PCB?
Is the thread cutter motor's lead
properly connected to CN6 on the
main PCB?
Does the machine function normally when the thread
cutter sensor PCB is replaced with a reliable one?
Is the resistance between pins 1 and 2, and
3 and 4 of the thread cutter motor 5.6 - 6.4Ω,
respectively, when the motor's connector
CN6 is removed from the main PCB?

Thread is not cut normally.

Y
Y
N
Y
Change main PCB.
N
Connect it properly.
N
Connect it properly.
Y
Change thread cutter sensor PCB.
N
Change thread cutter motor.
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