Stereo Scan 440 - DCU

6-10 Chapter 6 Fault Diagnosis! "I
Fitting a New LaB, roament
The new emitter should be fitted, accurately, according to Section 2.2.4 Changing
the Filament.
Running Up an LaB6 Filament
ALaB6 emitter should also be run up using the instrument's automatic procedure
(selcting Beam On from the gun control box on the toolbar). The procedure is
designed to maximise the filament life. Similarly the Beam Off procedure
should always be used to run the gun down.
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The only exception to this is when a Kimball LaB6 emitter is installed for the first
time. To ensure that the Kimball emitter is saturated at the correct filament
current (1.8-2.0A) it should be run up slowly using the Manual option and the
Gun Set Up panel. Once the filament has been saturated, the automatic routines
can be used safely.
The most imrortant factor of all in maximising LaB6 life is to ensure that the
emitter has been fully cooled down before exposing it to air, as otherwise, the
LaB6 crystal is liable to be severely damaged, or even destroyed.
LaB, Beam Current.
The beam current is fixed for LaB6 operation, and not user changeable.
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6.4. LEO Error Messages
There are many reasons why error messages may appears. With each message
on-line help is available. In addition an alphabetical list of all error messages is
included below.
6.4.1. E"or Messages
ACQUIRE COMMAND ERROR
This error is given when a signal acquisition command fails.
Code numbers greater than 40 indicate the failure of an internal consistency
check. Contact Leica
Code numbers less than 40 indicate that there is a failure in the communication
to the DSP subsystem.
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Stereoscan 440 Operator Manual
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