Introduction; Power-Up Error Messages And Led Codes - Xerox Phaser 8400 Service Manual

Introduction

This section covers troubleshooting procedures for the Phaser 8400 Printer using front
panel error messages and codes. Some procedures require running service diagnostic
test functions to verify that a specific printer part is operating correctly. For
information on Service Diagnostics and all internal printer test functions, see the table
"Diagnostic Mode Menu" on page 4-5.
To troubleshoot problems, such as startup and power on, media, paper path, print-
quality or image problems, and electrical failures not associated with a front panel
message or code, refer to the section "General Troubleshooting" on page 4-1.
If an error message or code is not visible on the front panel, the Service Usage Profile
report and Printer Status page list errors reported by the printer.

Power-Up Error Messages and LED Codes

The Phaser 8400 Printer has three sets of tests that are run when the printer is first
powered on: Built-In Self Tests (BIST), Power On Self Tests (POST), and Print
Engine Self Tests (PEST). BIST verifies basic Electronics Module CPU operation and
reports failures with interface panel LED blink codes ( A long flash represents a 5, while
a short flash is a 1. For example, a long flash followed by 4 short flashes is 5 + 4 = 9.
).
POST checks communication paths from the Electronics Module CPU to other parts
of the Electronics Module and to some other systems of the printer. PEST runs once
Postscript is operational, and checks for connection to and operation of, various
system components.
POST testing initializes the front panel and if an error occurs a POST error message
will be displayed on the front panel LCD. POST errors are also displayed using
interface panel LED patterns in case the communication path to the front panel has
failed.
Some POST errors are "soft" errors that do not prevent the printer from powering up
completely. These errors are displayed on the front panel for 5 seconds and then the
printer continues through the remainder of POST. Because soft errors do not stop the
printer from powering up, there are no rear panel LED codes associated with them.
Most soft errors will also cause the printer to print a Startup Page with the error
message on it. BIST and POST errors are not stored in the fault history logs.
3-2 Phaser 8400 Printer Service Manual