Here are the replacement steps:
1) Remove the left and right end caps. There are four flat head fasteners for each end cap.
2) Remove the front two fasteners of the top cover plate. The cover plate can then pivot upward. Put the fasteners back in the holes so the cover plate doesn’t fall forward and pinch the keypad cables on the right side. This will expose the top of the carriage.
3) Loosen the carriage belt tensioner all the way.
4) Remove the carriage cover screw in the front and on the left side. The carriage cover screw in the front locks the carriage on the rail. Remove the carriage cover.
5) Push down on the carriage and pull the bottom towards you carefully just enough so the wheels clear the rail. The carriage wheels on the bottom will unhook from the rail and pivot out allowing the carriage to lift vertically. Be careful not to over-rotate the carriage so the carriage position sensors at the top aren’t damaged. They straddle the rail at the top.
6) Loosen the belt fasteners on the back side of the carriage so the belt may be removed. In some instances, it may be necessary to remove the fasteners. Sometimes the clips will clear the fastener heads and the fasteners won’t need to be removed.
7) Remove the fasteners at the top that connect the carriage position sensor board to the carriage. Note how the cable is sandwiched between the bracket and the PCB so it is stress relieved. You will want to reassemble the same way. I recommend taking a couple pictures so you can see how it currently is assembled.
8) Exchange the wires in the terminal block one by one with the new carriage noting which wire goes into which position in the terminal block.
9) Reverse the steps above to reassemble.