Xerox 6250N Service Manual - Page 165

Power On Self Test (POST) The following tests are performed when the printer is powered on, after the boot loader runs, and before the operating system is loaded and initialized. POST diagnostics are intended to provide a quick means of isolating a defective subsystem associated with the Image Processor Board, SDRAM, and ROM. POST returns control to the boot loader and the operating system is loaded. The operating system then loads the imaging processing software. If POST detected any soft errors, a message is printed in a red box on the start page. If the start page has been turned off, POST forces a start page to be printed. If POST detects any hard errors, both the front panel and health LED blink the error code pattern, see "LED Blink Patterns" on page 4-6. POST Startup indications ■ At power-on, the hardware default is to turn on the Image Processor (IP) Board 'health' LED. ■ The IP Board 'health' LED is turned off. ■ The front panel display is reset (addressable area becomes "gray"). ■ The Green LED turns on for 1/3 second. ■ The Yellow LED turns on for 1/3 second. ■ The Red LED turns on for 1/3 second. ■ The front panel LED is turned off. ■ The backlight is turned on (high intensity), with nominal contrast display. ■ The front panel display area is turned on, dark black for 1 second. ■ The front panel display is cleared. ■ The backlight is turned on with nominal intensity. ■ The POST Vn.nn message appears, and tests are quickly executed in the order shown in the Post Test Sequence table. ■ If any tests fail, the front panel screen freezes with the name of the test displayed and the line posted is "Call Customer Service". ■ After the POST tests have finished running, the Xerox 'splash screen' is posted to the front panel and PostScript begins initialization. 4-4 Phaser 6250 Color Laser Printer Service Manual