Troubleshooting 83System Boot Sequence1. When the main power switch is turned on, the health LED on the Image ProcessorBoard turns on immediately.2. The boot loader checks for RAM present and functional. If not, it posts a verylarge ìRAM ERRORî on the front panel and blinks the LED 1/2 second on/offcontinuously.3. The boot Loader then runs POST diagnostics.4. POST turns off the health LED.5. Post checks the front panel.6. If keys have been pushed, the front panel displays ìProcessing Inputî.7. The front panel LED cycles: Green, Yellow, Red, and then off.8. The front panel turns on, the LED turns Green and the POST tests are run.Power On Self Test (POST)The following tests are performed when the printer is powered on, after the bootloader runs, and before the operating system is loaded and initialized.POST diagnostics are intended to provide a quick means of isolating a defectivesubsystem associated with the Image Processor Board and SDRAM. POST returnscontrol to the boot loader and the operating system is loaded. The operating systemthen loads the imaging processing software. If POST detected any soft errors, amessage is printed in a red box on the start page. If POST detects any hard errors,both the front panel and health LED blink the error code pattern, see "LED BlinkPatterns" on page 84.POST Startup indications At power-on the hardware default is to turn on the IP board ëhealthí LED. The Image Processor Board ëhealthí LED is turned off. The front panel display is reset (addressable area becomes ìgrayî). 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. If any tests fail, the front panel screen freezes with the name of the testdisplayed and the line posted is ìCall Customer Serviceî. After the POST tests have finished running, the Xerox ësplash screení isposted to the front panel and PostScript begins initialization.
