Changing the Aperture on a CE7000A

The 7000A is equipped with a lever that holds the sample arm away from the instrument while you change the aperture. It is called the “retaining lever” and is operated using the following steps: 

1. Pull the sample arm away from the viewport door.

2. Rotate the retaining lever upward until it stops.

3. Press down on the viewport door release button and rotate the sample
    door to the full open position. The aperture can now be either mounted or      
    removed.