Level Adjustment

Level adjustment is crucial in achieving a uniform contact between your mask and your sample.

On the MJB4, the sample chuck is pushed up by a center stage, which is attached to the base (the part that moves with the Contact Lever) magnetically and aligned with a pin (see attached picture)

Underneath the chuck is three flat head screws for level adjustment.

The way you tell whether your sample chuck is level with the mask, is by first following the normal procedure and making a test contact. 

Note: if the three screws are tightened all the way, it would reduce the stage height to a point where you cannot bring the sample up high enough to make contact with a regular glass mask.
If this starts to happen, you should turn the screws counterclockwise all the way, and start the level adjustment again from there.