A Needle Is Not Threaded Normally - Brother PR600II Service Manual

Failure Investigation for Electronic Parts A needle is not threaded normally.

A needle is not threaded normally.

Is the needle thread sensor's lead
properly connected to CN14 on the
main PCB?
Is the thread motor's lead properly
connected to CN6 on the main
PCB?
Does the machine function normally when the needle
thread sensor PCB is replaced with a reliable one?
Is the resistance between pins 1 and 2,
and 3 and 4 of the thread motor 4.7 - 5.7Ω,
respectively, when the motor's connector
CN6 is removed from the main PCB?
Y
Y
N
Y
Change main PCB.
N
Connect it properly.
N
Connect it properly.
Y
Change needle thread sensor PCB.
N
Change thread motor.
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