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Service Guide ML520/521
Chapter 3 Maintenance & Disassembly
3.1.03 Maintenance Precautions
1.Do not disassemble the unit if it is operating normally.
2.Before starting disassembly and assembly, always turn the AC power switch OFF and pull out the AC plug.
3.Detach the interface cable, if installed.
4.Do not remove parts unnecessarily. Try to keep disassembly to a minimum.
5.Use the recommended maintenance tools.
6.When disassembling, follow the listed sequence. Failure to follow the correct sequence may result in damaged parts.
7.Since screws, collars and other small parts are easily lost, they should be temporarily attached to the original positions.
8.When handling circuit boards use extreme care. Integrated circuits (microprocessors, ROM, and RAM) can be destroyed by static electricity.
9.Do not place printed circuit boards directly on conductive surfaces.
10.Follow the recommended procedures when replacing assemblies and units.
11.Perform the printhead gap adjustment procedure (Refer to Section 3.3 of this Service
Handbook) when the any of the following occur.
Print Quality is darker on one side of the document.
Parts are replaced
Printhead (3.2.02)
Space Motor Assembly (3.2.11)
Space Rack (3.2.13)
Guide Rail (3.2.15)
Platen Assembly (3.2.19)
Carriage Shaft (3.2.25)
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