Leica DM2000 Operating Manual page 62

11. Troubleshooting
Problem
Phase Contrast
No phase contrast is possible.
Polarization
No polarization contrast is possible.
Transmitted Light Interference Contrast
No transmitted light interference contrast is
possible.
62
Cause/Remedy
The specimen is too thick, too thin or too
brightly stained.
Refractive indiceses of the mounting medium
and specimen are identical, so that there is no
phase jump.
The cover glass is not placed planar.
Check the right light ring (→ p. 51).
Check the centering of the light rings
(→ p. 33f).
Check the condenser centering.
Open the aperture diaphragm completely.
Bring the polarizer and analyzer into cross po-
sition until they reach maximum darkness
(without specimen) (→ p. 53).
The specimen is too thick or too thin.
The embedding medium or specimen are of bi-
refringent material. Rotate the specimen.
The difference in the refractive indices of the
specimen and the embedding medium is too
small.
The cover glass is too thick.
Check the right condenser prism (→ p. 53).
Check the centering of the condenser prisms
(→ p. 34).
Check the Köhler illumination (→ S. 31).
Bring the polarizer and analyzer into cross po-
sition until they reach maximum darkness
(without specimen) (→ p. 53).