Xerox 8500DN Service Manual - Page 186

General Troubleshooting Miscellaneous Electrical Troubleshooting The Electronics Module contains the power supply, image processor board and the power control board. If a component of the Electronics Module fails, and service is necessary, the entire Electronics Module is replaced as a unit. No individual board troubleshooting is required. The printer contains many self test routines to aid in diagnosing problems. Note If the printer encounters certain fault conditions, the printer may reboot up to three times before displaying an error code. This is an attempt to correct the problem and reduce the number of unnecessary service calls. Following the suggested debug procedures, the specified sequence generally provides better test coverage than performing tests in a different order. Error Message Displayed on Control Panel LCD Printer has detected a fault condition. See "Fault Code Error Message Troubleshooting" on page 3-7 for definitions and solutions. Blank Display and the PS and PE LEDs Are Flashing an Error Code Printer has detected a fault condition but can't display a message on the LCD. Some portion of the chain of devices used to drive the LCD may be defective since an error message is not displayed. See "Fault Code Error Message Troubleshooting" on page 3-7 for definitions and solutions. Printer Fails Power-Up: PS, PE and 3.3 V LEDs Do Not Illuminate Printer is not receiving proper AC. Caution Use caution with hazardous voltages when diagnosing AC problems. The 3.3 V LED is located inside the Electronics Module and must be observed through the vent holes close to the AC power switch, see the illustration on page 4-64. 1. Inspect the power cord. a. Verify AC outlet voltage and current capacities are within specifications. b. If necessary, move the printer to a different outlet and retest. 2. Transient on AC line tripped protective circuitry in printer power supply. Cycle power to printer to reset protective circuits in power supply. 3. Short circuit on 3.3 V supply within the Electronics Module. ESD damage to the printer may occur if static electricity is discharged to printer electronics a. With power cord connected, touch the metal Electronics Module to discharge any static electricity. b. Turn off printer and wait 30 seconds for power supply capacitors to discharge. Damage to circuits within the Electronics Module may occur if the power supply capacitors are not allowed to fully discharge. 4-56 Phaser 8400/8500/8550/8560 Color Printer Service Manual