UMAX Data Systems Astra 1220U, Service Manual

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Service Manual
5. Environment vs. Performance
What’s in this Chapter:
•
Overview
•
Shock and Vibration
•
Temperature
•
Humidity
•
Dust
•
Aging
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
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