Brother NV4000D Service Manual page 380

Bobbin Winder Mechanism
Perform wiring operation in accordance with a following procedure.
6 - 12
Push around here.
1. Pass the BW motor lead wire and the
BWSW lead wire over a coating clip as
shown in left picture.
2. Bend the coating clip toward left.
3. Bend the coating clip toward right.
4. There should be some slack in the BW
motor lead wire. (Make sure the lead
wire touches the BW motor when the
lead wire is pushed.)