14
Optical
Problem
Possible Cause
Vignetting or uneven brightness in the field of view or
field of view only partially visible
Lamp not installed properly
Lamp not centred
Diffuser is in intermediate position
Condenser not mounted correctly
Condenser is not centred
Condenser is set too low
Condenser top lens not fully swing in/out (Swing-out condenser)
Field diaphragm closed too far
Aperture diaphragm closed too far
Improper condenser objective combination
Revolving nosepiece not clicked into position
Trinocular eyepiece tube optical path selector lever in intermediate position
Dust or dirt in the field of view
Aperture diaphragm closed too far
Condenser is set too low
Dust or dirt on specimen surface
Dust or dirt on field lens, filter, condenser or eyepiece
Poor image
(low contrast or resolution)
Condenser is set too low
Aperture diaphragm closed too far
No cover glass
Too thick or thin cover glass
Immersion oil not used on immersion procedure
Air bubbles in immersion oil
Specified immersion oil used not used
Immersion oil on dry objective
Greasy residue on eye lens
Incorrect illumination
Unequal focus
Stage installed on inclined plane
Specimen holder not fixed securely on stage
Specimen not secured in position
Image tinged yellow
Lamp voltage is set too low
Blue filter is not being used
Focusing is not possible with high magnification objectives
Slide is upside down
Cover glass is too thick
High magnification objectives strike the specimen when
changing over from low to high magnification
Slide is upside down
Cover glass is too thick
Eyepiece diopter not adjusted
7. Troubleshooting Table
As you use your microscope, you may occasionally experience
a problem.
The troubleshooting table below contains the majority of fre-
quently encountered problems and the possible causes.
