Phaser 7700 Color Laser Printer Service Manual 2-33POST FaultsThere are two kinds of faults: Soft and Hard.A soft fault is any fault that is discovered by POST but does not prevent theoperating system from initializing and becoming available as a tool fortroubleshooting. These POST faults do not stop execution and are reportedon the StartPage, in a red box, after the system is running.A hard fault is any fault discovered by POST that prevents the operatingsystem from initializing successfully. A hard fault prevents the system fromfurther execution and is halted with blinking LEDs (front panel and healthLED). The test name of the test that failed is displayed on the front panel.Note With the DIP switches in service mode, a soft fault isconverted to a hard fault.Fault Reporting DevicesThere are four fault presentation devices. 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.■ All soft faults are printed on the StartPage (when the DIP switches arein Customer Mode), see You can print a service Diagnostics menumap by highlighting “Print Service Menu Map”, using the arrow keyand pressing OK. on page 2-35.LED Blink PatternsFor faults identified as hard faults, the POST firmware causes the PS healthLED to blink in a particular pattern to identify the fault. There are short andlong blinks. A long blink is worth 5 and a short blink is worth 1. If a fault blinkpattern is flashed as long, long, short, short, this is fault code 5+5+1+1=12.The exception to the above pattern is a RAM test error. The RAM tests have aspecial blink pattern and the front panel displays “RAM Error.”During power up the front panel LED is On. If the RAM tests fail, the ImageProcessor Board health LED is turned Off, and the front panel LED is red. At1/2-second intervals, the health LED and the front panel LED togglecontinuously.
