Post Faults; Fault Reporting Devices; Led Blink Patterns - Xerox phaser 6250 Service Manual

POST Faults

There are two kinds of faults: soft and hard.
A soft fault is any fault that is discovered by POST, but does not prevent the operating
system from initializing and becoming available as a tool for troubleshooting. These
POST faults do not stop execution and are reported on the StartPage in a red box after
the system is running.
A hard fault is any fault discovered by POST that prevents the operating system from
initializing successfully. A hard fault prevents the system from further execution and
is halted with blinking LEDs (front panel and health LED). The test name of the test
that failed is displayed on the front panel.

Fault Reporting Devices

There are four fault presentation devices.
■
All soft faults are printed on the StartPage.
For hard faults:
■
The health LED flashes according to the fault code.
■
The front panel LED flashes in unison with the health LED.
■
The last posted message to the graphic front panel is present.

LED Blink Patterns

For faults identified as hard faults, the POST firmware causes the IP health LED to
blink in a particular pattern to identify the fault. There are short and long blinks. A
long blink is worth 5 and a short blink is worth 1. If a fault blink pattern is flashed as
long, long, short, short, this is fault code 5+5+1+1=12, which indicates a failure in the
CPU interupt test. See "POST Diagnostics Test Descriptions" on page 4-7.
The exception to the above pattern is a RAM test error. The RAM tests have a special
blink pattern and the front panel displays "RAM Error". During power up the front
panel LED is on. If the RAM tests fail, the Image Processor Board health LED is
turned off, and the front panel LED is red. At 1/2-second intervals, the health LED
and the front panel LED toggle continuously.
4-6 Phaser 6250 Color Laser Printer Service Manual