Step 3: further dismantling and cleaning

To completely open up the machine, you remove the carriage. Pull the carriage all the way to the left and  loosen the screw on the back rail (see black arrow) and pull the carriage off.

Next, unscrew the two screws that hold the remaining part of the cover (see white arrows).  The machine is now completely open and can be fully disassembled for cleaning.

Under the carriage, there is a black wedge that comes up when you push the shift button. This slides onto the axis.

Step 4: