OPTO-EDU A63.7069, Instruction Manual

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7. Maintenance
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Normally, the user can not open the cover plate, in order to avoid the damage to operator.
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Without the guidance of the engineer, the user can not move the position of the SEM, in order
to avoid the damage to instrument.
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This chapter includes following contents: replacing filament and Alignment of Mechanical
Correction, replacement of scintillator of SE detector, check the level of oil in mechanical
pump, check the air desiccator, cleaning of Final Aperture Assembly, stop use SEM for long
term.
7.1. Replacing Filament and Alignment of Mechanical Correction
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The lifespan of filament is dependent on emission current, heating current and vacuum
degree.
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If the display of Beam current change to 0 suddenly, and the screen change to black also, when
normally working, which means the filament is breakdown. It is needs to replace a new one.
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If the value of Beam current always display 0, that means the filament is broke down or there
are some other reasons, such as loose contact, too large deflection of filament. It is needs to
replace a new filament or check the connection of filament and adjust the alignment of the
filament.
Steps of replacing filament are as follows:
1. Click the [OFF] button, close V1, click the [Gun] button, the color of button will change to YELLOW,
V3and V4 will be opened.
2. Take off the cap of gun and take down the filament assembly (wehnelt cap).