Technical data

MD400 Scanner Pocket Service Guide 9
SOFTWARE DYNAMICS GmbH (Germany)
Contacts : Mr Thomas Deharde
Mr Dick Dirks
Mrs Sharon Dirks
Phone: [phone]
FAX : [phone]
Business hours: 09.00 to 17.00
(local time) Monday to Friday
3.3 Shading Correction
If the symptoms are uneven shading, cycle the
power on/off and re-scan.
NOTE
It is necessary for the scanner power to be
periodically cycled in order for the correction
to be fully effective.
The MD400 incorporates shading correction to
compensate for the effects of:
• Uneven illumination
• Uneven sensitivity of CCD elements
• Uneven lens characteristics
• Effects of ageing.
The correction is done by using data stored in a
correction memory. Data is automatically acquired
in the correction memory on power-up, by reading
a plain white tape which is built into the scanner.
3.4 Hardware Service Strategy
Localise the fault using built-in tests and replace
the defective field replaceable unit (FRU). Refer to
Section 4 for the FRU list.