Van Guard 1200CM Series, Operation Manual

Setup

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Once the phase contrast condenser assembly has been centered, the phase contrast 

annulus rings must be centered for the objectives.  Phase contrast is a system which 

involves  a  series  of  light  baffling  annular  rings.    Proper  alignment  of  these  rings  is 

absolutely necessary to achieve phase contrast.

Aligning the Phase Contrast Annulus Rings

Begin by turning on the substage illuminator with the power switch.  
Set the objectives so they are in the approximate position for actual use.  This is best 

achieved by placing a slide on the stage, rotating the 100X objective into position, 

and raising the stage until the tip of the 100X objective is just above the slide (almost 

touching).  
Rotate the nosepiece until the 10X objective is in the light path.

Rotate the annuli turret in the phase contrast condenser assembly until the “10” is 

seen in the viewing window.  
Remove an eyepiece from one of the eyetubes and replace with the phase contrast 

centering telescope.

Looking through the phase contrast centering telescope, turn the uppermost piece 

of the phase contrast centering telescope until the image is in focus.
The image seen through the phase contrast centering telescope should resemble 

rings superimposed on one another (see Figure 7).  What is actually being viewed 

are the phase rings.  Holding a white sheet of paper on the stage and sliding back 

and forth between the objective and stage will make this easier to see.
Turn the phase annuli centering knobs, which extend from the phase contrast 

condenser assembly, until the two rings of light are centered upon one another (see Figure 8).

Once the phase rings are centered, remove the phase contrast centering telescope and replace with the eyepiece.
The phase rings are now centered for the other remaining objectives.  This process shouldn’t need to be repeated 

for each objective setting, although it is advised to perform off and on checks with the phase contrast centering 

telescope to confirm that the phase rings are still centered.

NOTE:  Brightfield work can be achieved on models with a phase contrast condenser.  The “0” setting on 

the phase annulus turret is used for this purpose.

Verifying that the illuminator is centered will allow maximum light to reach the specimen.  This adjustment is usually 

not required as our microscopes are shipped with the illuminator pre-centered.  If for some reason the illuminator 

should need to be centered again follow the instructions below.  

Centering the Illuminator

Remove the substage collector by loosening the set screw on the left hand side.

The bulb filament should be centered in the opening.  If it is not, loosen the bulb centering mechanism on 

the bottom of the microscope.

Reposition the bulb so that the filament is at the center of the opening.  Make sure that the reflector beneath 

the bulb is aligned with the light bulb access door so that the access door can still be opened.
Tighten the bulb centering mechanism.
Reinstall the substage collector.

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All Models

Phase Contrast Models

If you purchased a brightfield model this completes your setup.  Skip ahead to page 10, “Using your 

1200CM Series Microscope”.  If you purchased a phase contrast model, continue below.

Figure 7

Figure 8