General Troubleshooting 4-59Electronics TroubleshootingPrinter Power-Up SequenceThe following lists the chain of events that occur when you turn on a printer. You canfollow this list as one means of determining if the printer is operating correctly. Theexact chain of events depends upon the last power down condition and where theprinter has last determined the printhead is positioned, this is stored in non-volatileRAM. The Electronics Troubleshooting Checklist is the primary reference fortroubleshooting power-up problems.1. Power cord is plugged in and the power switch is turned on:2. Power supply senses AC line voltage conditions (110 VAC or 220 VAC) andenables DC voltages. If an overload occurs, the printer turns off the high voltageDC supplies, causing a “blink” effect on the Control Panel LEDs.3. BIST test flashes the PE LED very briefly at a fast rate until the end of the nexttest.4. The Boot loader performs CPU initialization and RAM test. It then sends theboot loader version to the serial port.5. Power-On Self Test (POST) initializes the Control Panel. The Control Panel LEDturns red, green, orange, and then off. The Control Panel LCD then goes blackand then clear. The POST version displays on the LCD and waits two seconds.During this time the operator can press the Back button to bypass the remainingPOST test.6. Low level Power-On Self Test (POST) diagnostics are performed. The ControlPanel displays status messages as each sub-test is performed. This test takesabout 8 seconds. All LEDs are off during the test.If POST diagnostics pass, the Control Panel displays the Xerox logo and turns onthe green LED.If the test detects an error, the error message displays on the LCD and the printerflashes the LEDs with a repeating error code pattern.7. The VxWorks operating system is initialized and engine code is started. Thistakes about 15 seconds. The Xerox logo is displayed.8. Print Engine Self Test (PEST) diagnostics are then performed. These test theheaters, clutches, motors and solenoids. As each clutch is tested, you hearclicking with four high tones as each motor is tested. This test takes about 30seconds.9. The printer now runs the mechanical initialization. The exact sequence dependson the initial position of the printhead and wiper assembly.
