VWR VisiScope 400 Serie Manual De Instrucciones página 12

Centering the ring
► Usually this operation is not needed.
If necessary, please proceed with the
following steps:
1. Place a specimen on the stage and focus
it.
2. Take out the eyepiece from the tube without
the dioptric adjustment, and replace it with
the centering telescope (CT). (Fig.26)
3. Check that the phase ring and the objective
correspond, and that both are steadily set
on a click stop.
4. Use the CT to focus on the light ring's image
① and the phase contrast ring's image ②.
If the light ring's image is not sharp, adjust
the CT's eyepiece until you can see a clear
image of the light ring.
5. Adjust the bolts of the two centering
holes in the phase contrast slider using a
screwdriver until the light ring center and
the phase contrast ring center coincide.
6. The 10X and the 20X phase contrast
objectives use the same ring on the phase
contrast slider. The coincidence of the light
ring center and the phase contrast center
must be verified with both objectives.
(Fig.27; Fig.28)
► If the light ring is centered incorrectly,
the contrast will be severely impaired.
► The phase ring may need recentering
during and after observation of very
thick specimens.
► The phase ring may show an apparent
misalignment if the cover glass is not
flat.
②
12
①
Fig.26
Fig.27
Fig.28