• Code: 4200
• Description: BD error (laser scanner unit) error
• Causes: BD sensor does not detect laser beam due to condensation on the polygon mirror. Defective laser scanner unit. Defective control PWB.
• Remedy: BD sensor does not detect laser beam due to condensation on the polygon mirror. Turn printer power off for at least 30 minutes, then turn printer on again. If not cured, replace the laser scanner unit.
  Defective laser scanner unit. Replace the laser scanner unit.
  Defective control PWB. Replace the control PWB.

• Code: 6000
• Description: Broken fuser heater lamp wire
  The fuser temperature does not rise after the fuser heater lamp has been turned on.
• Causes: Poor contact in the fuser thermistor connector terminals. Poor contact in the fuser heater lamp connector terminals. Fuser thermistor installed incorrectly. Fuser thermal cutout triggered. Fuser heater lamp installed incorrectly. Broken fuser heater lamp wire.
• Remedy: Poor contact in the fuser thermistor connector terminals. Reinsert the connector.
  Poor contact in the fuser heater lamp connector terminals. Reinsert the connector.
  Fuser thermistor installed incorrectly. Replace the fuser unit.
  Fuser thermal cutout triggered. Replace the fuser unit.
  Fuser heater lamp installed incorrectly. Replace the fuser unit.
  Broken fuser heater lamp wire. Replace the fuser unit.

• Code: 6020
• Description: Abnormally high fuser thermistor temperature
  Fuser thermistor detects abnormally temperature.
• Causes: Shorted fuser thermistor. Defective control PWB.
• Remedy: Shorted fuser thermistor. Replace the fuser unit.
  Defective control PWB. Replace the control PWB.

• Code: 6030
• Description: Broken fuser thermistor wire
  Input from fuser thermistor is 0 (A/D value).
• Causes: Poor contact in the fuser thermistor connector terminals. Broken fuser thermistor wire. Fuser thermistor installed incorrectly. Fuser thermal cutout triggered. Fuser heater lamp installed incorrectly. Broken fuser heater lamp wire.
• Remedy: Poor contact in the fuser thermistor connector terminals. Reinsert the connector.
  Broken fuser thermistor wire. Replace the fuser unit.
  Fuser thermistor installed incorrectly. Replace the fuser unit.
  Fuser thermal cutout triggered. Replace the fuser unit.
  Fuser heater lamp installed incorrectly. Replace the fuser unit.
  Broken fuser heater lamp wire. Replace the fuser unit.

• Code: 6400
• Description: Zero cross signal error
  The zero cross signal does not reach the control PWB for specified time.
• Causes: Defective harness between high voltage PWB (YC202) and control PWB (YC23), or improper connector insertion. Defective connection between power source PWB (YC103) and high voltage PWB (YC201). Defective power source PWB. Defective control PWB.
• Remedy: Defective harness between high voltage PWB (YC202) and control PWB (YC23), or improper connector insertion. Reinsert the connector. Also check for continuity within the connector harness. If none, remedy or replace the harness.
  Defective connection between power source PWB (YC103) and high voltage PWB (YC201). Reinsert the connector.
  Defective power source PWB. Replace the power source PWB.
  Defective control PWB. Replace the control PWB.

• Code: 7990
• Description: Waste toner full
  The waste toner sensor has detected that the waste toner reservoir (drum unit) is full.
• Causes: Waste toner reservoir (drum unit) is full. Defective waste toner sensor. Defective control PWB.
• Remedy: Waste toner reservoir (drum unit) is full. Turn the main power switch off/on to restart the printer. If the error is not resolved, replace the drum unit.
  Defective waste toner sensor. Replace the waste toner sensor.
  Defective control PWB. Replace the control PWB.

• Code: F000
• Description: Control PWB - Operation panel PWB communication error
• Causes: Defective harness between operation panel PWB (YC1) and control PWB (YC7), or improper connector insertion. Defective operation panel PWB. Defective control PWB.
• Remedy: Defective harness between operation panel PWB (YC1) and control PWB (YC7), or improper connector insertion. Reinsert the connector. Also check for continuity within the connector harness. If none, remedy or replace the harness.
  Defective operation panel PWB. Replace the operation panel PWB.
  Defective control PWB. Replace the control PWB.

• Code: F020
• Description: Control PWB RAM checksum error
• Causes: Defective main memory (RAM) on the control PWB. Defective expanded memory (DIMM).
• Remedy: Defective main memory (RAM) on the control PWB. Turn the main power switch off/on to restart the printer. If the error is not resolved, replace control PWB.
  Defective expanded memory (DIMM). Replace the expanded memory (DIMM).