System Start-Up And Post; Power On Self Test (Post) - Xerox Phaser 4500 Service Manual

System Start-Up and POST

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 and SDRAM. 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 POST detects any hard errors,
both the front panel and health LED blink the error code pattern, see "LED Blink
Patterns" on "LED Blink Patterns" on page 3-17.
POST Startup indications
At power-on the hardware default is to turn on the IP board 'health' LED.
The Image Processor Board 'health' LED is turned off.
The front panel display is reset (addressable area becomes "gray").
The Red LED turns on.
The backlight is turned on (normal intensity), with nominal contrast display for
1/4 second.
The front panel display area is turned on, dark black for 1/4 second.
The front panel display is cleared for 1/4 second.
The backlight is turned off with nominal intensity for 1/4 second.
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 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.
3-16 Phaser 4500 Service Manual