2-58 Phaser 4400 Laser Printer Service ManualImage Processor POST Error CodesThe Image Processor Power-On Self-Test (POST) detects two major types of faults: Hard faults are those that are known to prevent initialization of the operatingsystem used by the Image Processor board CPU. Soft faults are those that are not a core resource to the operating system, anddo not prevent it from initializing and becoming available as a tool fortroubleshooting. Soft faults are reported on the Startup Page after the systemis running.Fault Reporting DevicesThere are four fault presentation devices: the health LED, the Front Panel LED, theFront Panel display, and the Start Page. (Refer to Image Processor Board onpage 1-10 for the health LED location on the Image Processor Board.) These devicesare used only after initial tests indicate they are functioning properly.For hard faults: The health LED blinks according to the fault code. The Front Panel LED blinks in unison with the health LED. The last posted message to the Front Panel display is present.For soft faults: All soft faults are printed on the Start Page.LED Blink PatternsFor faults identified as hard faults, the POST firmware blinks the Health LED in aparticular pattern of short and long blinks to identify the fault. A long blink is worth 5and 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. Note that for test 5, the blink pattern is five shortblinks.The exception to the pattern just described is a RAM test error. The RAM tests have aspecial blink pattern and the front panel displays RAM Error. During power-on thefront panel LED is on. If the RAM tests fail, the Image Processor Board health LEDturns off, and the front panel LED is red. At 1/2-second intervals, the health LED andthe front panel LED toggle continuously.
