Baby Lock Pro-Stitcher BLPS3 Instruction And Reference Manual page 19

4. Align the new Y-Encoder circuit board so the five pins
on the encoder fit into the five-pin connector on the
circuit board and gently push into position. The screw
hole on the circuit board should match up with the
hole in the encoder housing.
5. Replace the Phillips screw.
6. Plug the stitch regulator cable into the new Y-encoder circuit board.
Pro-Stitcher User Manual Installation | 3.9