Brother BAS-416A Supplementary Manual page 3

Now turn the shaft counterclockwise very slowly until just 2 is flashing.
Install the new color change potentiometer onto the machine by inserting the
shaft in to the color change collar and also that the mounting bracket goes into
the slot. Make sure not to turn the shaft while inserting it into the machine. Then
tighten the two outer setscrews to hold it into position. If you have to rotate the
collar to get to the second setscrew, make sure that one is tightened before
rotating.
Setscrews
Color change collar
Potentiometer
Slot
Slowly rotate the color change collar counterclockwise so that needle 2 is still
displayed and that the "N" changes to an "O" on the needle bar selection screen
that is displayed on the right of the screen. This "O" means that the machine is
directly on needle number 2.
Check to make sure that the needle the machine is on matches the needle
displayed by color changing with the arrow keys and checking all the needles.
Press the End key when done.
Make sure to reinstall any wire ties or clips that hold the wire of the potentiometer
and you are finished.