Bobbin Winding Cannot Be Done - Brother PE770 Service Manual

Failure Investigation for Electronic Parts Bobbin winding cannot be done
5 - 14
Bobbin winding cannot be
done.
Is the bobbin winder mechanism
assembled and attached correctly?
Y
Is the resistance between the bobbin
winder assy. connector pins 1 & 2
normal?
• Bobbin winder shaft in bobbin wind
position .......... 1 Ω or less
• Bobbin winder shaft not in bobbin
wind position ... ∞
Y
Is the FFC connected correctly
between the main PCB (CN5) and the
motor PCB (CN1)? Are both connector
locks applied correctly? Is the FFC
free breakage or short circuit?
Y
Replace the main PCB assy.,
or
Replace the motor PCB assy.
N
Reassemble the bobbin
winder mechanism.
N
Replace the BW switch assy.
N
Connect the FFC or replace it.