Leica Microsystems DM2000 Manuel D'utilisation page 120

7. Start-up
Caution:
In older lamps, the structure of the arc is no
longer clearly recognizable. The image is
then more like that of a HG 50 lamp. The im-
age and mirror image can no longer be su-
perimposed exactly. In this case, align both
images.
• Using the collector, defocus the image with
the knob (41.6) until the arc image and mirror
image are no longer recognizable and the im-
age is homogeneously illuminated.
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