(Be sure to have a copy or the FW-1000 Manual for the final software alignment of the Filter Wheel)
Step 1: You will need the following tools to adjust the encoder: a Phillips screwdriver, a 3/32” Allen wrench and a.050” Allen wrench.
Step 2: Remove the nine 4-40 flat head Phillips screws from the case and remove the top cover. The cover should just clear the motor housing. On some older models, the cover will not clear the housing and the DB-9 connector may have to be removed with a 3/16” wrench first.
Step 3: Remove the filter wheel body from the housing with a 3/32” Allen wrench. Don’t remove the button head screws entirely as they will hold the lower felt washers in place when the unit is removed.
Step 4: Locate and mark the position of the filter wheel Optical encoder disk with a pencil next to its opening. Next, rotate the wheel manually until the .050” set screw is visible from the opening.
Step 5: Insert a .050” Allen wrench into the encoder disk set screw and loosen the screw. Rotate the filter wheel for ½ of the opening distance, (approximately 1”), while holding the Allen wrench and encoder wheel in place. Check that the encoder wheel is still at the axial distance marked by the pencil line and reset the setscrew.
Step 6: Finally adjust the software offset to center the wheel with the opening in the body. The instructions are in the filter wheel manual and reprinted here.
Now that the wheel is centered, replace the wheel body into the case in reverse order. The button head screws that hold the four corners of the body must be completely hand tightened and then turned back ½ turn to allow the felt to absorb vibrations. Finally, repeat part 9 above and check that the wheel is still centered upon power up.