4-2 Phaser 7400 Color Printer Service ManualIntroductionThis section covers the start-up, Power On Self Test (POST), Service Diagnostics, andpower supply operations of the printer to aid in troubleshooting problems notassociated with a reported error. For problems associated with an error message orcode, see "Error Messages and Codes" on page 3-1. Troubleshooting tips are availableon the Xerox website at: www.xerox.com/office/7400support.Troubleshooting procedures isolate a problem to a specific component orsubassembly. If you go through the procedures and are still unable to solve theproblem, re-read the “Theory of Operation” section for the problem area tounderstand how that section of the printer functions.System StartupListed here is a typical startup routine from a cold start. The printer requiresapproximately 45 seconds to complete this sequence.1. When the power switch is turned On, the ‘Health’ LED on the Image ProcessorBoard turns on immediately.2. System RAM is tested. If an error is detected, RAM ERROR displays and one orboth of the Control Panel and Health LEDs alternately blink at 1/2 secondintervals.3. The Boot Loader then loads and runs POST diagnostics.4. POST turns off the Health LED.5. POST checks the Control Panel.6. POST checks the keypad buffer. If a shortcut has been selected, the printerdisplays Processing Input and the shortcut executes. If a random button ispushed, or there is an indication of a button press, Processing Input displays andPOST continues. If no buttons have been pushed, POST continues execution.7. The display is reset (addressable area turns “Gray”).8. The Control Panel LED cycles: Green, Yellow, Red, and then Off.9. The display backlight turns on (high intensity), with nominal contrast display.10. The display area is turned on, dark Black for 1 second.11. The display is cleared.12. The display backlight turns on with nominal intensity.13. The POST Vn.nn message displays, and tests are quickly executed.14. For Hard Faults, the display indicates the last test run and “CALL SERVICE”.15. After the POST tests have successfully finished, the Xerox ‘splash screen’displays on the Control Panel and PostScript begins initialization.16. If the printer is able, the display reads Warming up - Please wait.17. When the final operating state of the printer is determined, the printer displays amessage and LED color, Red, Yellow, or Green to indicate its condition.
