Lexmark T420, Service Manual

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General Information
1-1
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1. General Information
The Lexmark™ T420(n) laser printer is a monochrome laser printer
designed for single users or small workgroups. There are two
models:
•
The T420 Base printer, with 16MB of memory standard, a
parallel port, and a USB port.
•
The T420 Network printer, with 32MB of memory standard, an
integrated Ethernet adapter, a parallel port, and a USB port.
The purpose of this chapter is to provide an overview of the
capabilities of the printer and available options for each of the
T420 models.
Note: Unless otherwise noted, all references to the Lexmark
T420(n) laser printer are intended to refer equally to both the
T420 Base and the T420 Network models.
Maintenance Approach
The diagnostic information in this manual leads you to the correct
field replaceable unit (FRU) or part. Use the error code charts,
symptom index, and service checks to determine the symptom and
repair the failure. See
“Diagnostic Information” on page 2-1 , for
the location of each section. See the “Repair Information” on
page 4-1 to help identify parts. After completing the repair, perform
tests as needed to verify the repair.
Special Tools
Long Phillips screwdriver (approximately 6–inch shank)
Slotted screwdriver
Small Phillips screwdriver
When taking voltage readings, always use the printer frame as
ground unless another ground is specified.