4-6 Phaser 6250 Color Laser Printer Service ManualPOST FaultsThere are two kinds of faults: soft and hard.A soft fault is any fault that is discovered by POST, but does not prevent the operatingsystem from initializing and becoming available as a tool for troubleshooting. ThesePOST faults do not stop execution and are reported on the StartPage in a red box afterthe system is running.A hard fault is any fault discovered by POST that prevents the operating system frominitializing successfully. A hard fault prevents the system from further execution andis halted with blinking LEDs (front panel and health LED). The test name of the testthat failed is displayed on the front panel.Fault Reporting DevicesThere 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 PatternsFor faults identified as hard faults, the POST firmware causes the IP health LED toblink in a particular pattern to identify the fault. There are short and long blinks. Along blink is worth 5 and a short blink is worth 1. If a fault blink pattern is flashed aslong, long, short, short, this is fault code 5+5+1+1=12, which indicates a failure in theCPU 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 specialblink pattern and the front panel displays “RAM Error”. During power up the frontpanel LED is on. If the RAM tests fail, the Image Processor Board health LED isturned off, and the front panel LED is red. At 1/2-second intervals, the health LEDand the front panel LED toggle continuously.
