Xerox 4400DT - Phaser B/W Laser Printer, Service Manual, Page: 40 / 503

Phaser 4400 Laser Printer Service Manual 2-3
Service Technician Cautionary Statements
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Always turn off the printer and remove the AC power cord, unless instructed
to do otherwise in a procedure. This is particularly important when checking
continuity between wiring.
■
If the printer is kept ON, never touch the conductive parts.
■
Wear an electrostatic discharge wrist strap to help prevent damage to the
sensitive electronics on the printer circuit boards.
■
Wait at least 5 minutes after you have switched OFF the printer power for
the Fuser to cool before you work on or around the Fuser.
■
If checking a specific part with the covers removed and the interlocks, safety
and power switches ON, laser beams may be irradiated from the Laser Unit
causing a health hazard. Observe proper precautions at all times.
■
When using service diagnostics to turn motors, drives and/or gears, never
touch or interrupt the moving parts as damage to the printer will result.
Procedures
Using the Troubleshooting Procedure
s
1. Each Step in a Troubleshooting Procedure instructs you to perform a certain action
or procedure. The steps are to be followed sequentially in the order given until the
problem is fixed or resolved.
2. The Actions and Questions box contains additional information and/or additional
procedures you must follow to isolate the problem.
3. When a procedure instructs you test a component using service diagnostics, see
Service Diagnostics on page 2-7 for the detailed steps and functions for testing
parts of the printer.
4. The action is followed by a question. If your response to the question is “ Yes” ,
then follow the instructions for a “ Yes ” reply. If your response to the question is
“ No” , then follow the instructions for a “ No ” reply.
5. Troubleshooting Procedures may ask you to take voltage readings or test for
continuity at certain test points within the printer. For detailed diagrams, refer to
the section
Wiring Data on page 9-1 for complete information on test point
locations and signal names.
6. Troubleshooting Procedures often ask you to replace a printer component. The
section
FRU Disassembly on page 6-1 provides detailed steps for removing and
replacing all major parts of the printer. The section Parts Lists on page 7-1 details
the location, quantity and part number for all spared parts of the printer.