ZEISS
7 Troubleshooting | 7.2 Column
7.2.2.4.4 Installing the Brass Retaining Washer | LaB₆
The tip of the LaB₆ filament needs to be located at a distance of 0.375 mm below the top of the
firing unit (Wehnelt cap).
To adjust the filament tip to this position, you need to install and tighten the brass retaining
washer. You also need to adjust the grub screws to center the filament.
You need to check the correct filament distance and the centering of the filament with a stereo
microscope or with a hand lens.
Info
If the filament is not accurately centered or if the filament distance is not correctly adjusted,
then this may negatively affect the filament lifetime and the performance.
NOTICE
Contamination by dust particles or fingerprints
Dust particles or skin grease can cause contaminations, which lead to flashovers or to bad vac-
uum.
4
Wear lint-free gloves throughout the whole procedure of replacing the filament.
Parts and Tools
Lint-free gloves
Stereo light microscope or a magnifying glass
Prerequisite
ü
The filament holder is inserted into the firing unit.
Procedure
1. Insert the brass retaining washer.
2. Use the adjust key to gradually tighten the
brass retaining washer until the filament is flush
with the top of the firing unit.
Instruction Manual ZEISS EVO | en-US | Rev. 10 | 354706-0780-006
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Summary of Contents for EVO
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