Environment Vs. Performance; Overview; Shock And Vibration; Temperature - UMAX Data Systems Astra 1220U Service Manual

5. Environment vs. Performance

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Overview

The Astra 1220U offers excellent performance, but, (as with other high end products), in a limited range of
environments. Astra 1220U performance drops, and perhaps will fail, under adverse environmental
conditions. For correct diagnosis of malfunctions, it is important to understand the relationship between
environment and performance.

Shock and Vibration

The image sensing unit (chassis assembly) is precisely aligned by several adjustment procedures. This
guarantees maximum resolving power. This component is especially sensitive to shock and vibration. If the
scanner is unintentionally dropped, as may occur in the shipping process, the drop could cause some of the
optical components to become misaligned. Misalignment has a negative effect on the Modulation Transfer
Function (MTF) of the optical system. The following information might be useful in correcting a problem
caused by misalignment:
Make sure all the screws on the optical assembly are tight and all of the optical components
are firmly secured in their respective locations to avoid the dislocation of components such
as the optical assembly's guide shaft.

Temperature

Significant changes in temperature can cause thermal expansion. Under severe conditions, permanent
damage can be done because of irreversible changes in the physical properties of certain materials. For
example, the timing belt loses its creep resistance at temperatures below -40 degrees centigrade. After it
has reached this point, the belt will usually lengthen. The following information should be helpful to you in
maintaining the Astra 1220U:
1. Never expose the scanner to temperatures above 50 degrees centigrade or below -40 degrees centigrade.
2. Operation of the Astra 1220U in a low temperature situation could produce the following phenomena:
a. dim lamp
b. rough chassis assembly movement
c. unusually loose timing belt
Overview
Shock and Vibration
Temperature
Humidity
Dust
Aging
Service Manual
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