• Code: 7220
• Description: Broken in-machine thermistor wire The sensor input sampling value is greater than the reference value.
• Remedy: In-machine temperature sensor 1. Confirm that the wiring connector is firmly connected, Insert the connector all the way in. In-machine temperature sensor - Main/engine PWB (YC1) 2. If the wiring is disconnected, shortcircuited or has a ground fault, replace the wire. Replace the in-machine temperature sensor PWB.
  Main/Engine PWB Replace the main/engine PWB.

• Code: 7800
• Description: Broken outer thermistor wire The sensor input sampling value is abnormal. (After detecting an error, it is controlled at 23C/77 °F and 50%RH)
• Remedy: Temperature and humidity Sensor 1. Confirm that the wiring connector is firmly connected, and if necessary, connect the connector all the way in. Temperature and humidity sensor - Main/engine PWB (YC2) 2. If the wiring is disconnected, shortcircuited or has a ground fault, replace the wire. 3. Replace the Temperature and humidity sensor PWB.
  Main/Engine PWB Replace the main/engine PWB.

• Code: 7990
• Description: Waste toner full The waste toner sensor detected the waste toner reservoir in the drum unit is full
• Remedy: Drum unit Turn the power switch off and on Replace the drum unit if not repaired.
  Waste toner sensor Replace the waste toner sensor.
  Main/Engine PWB Replace the main/engine PWB.

• Code: F000
• Description: Communication error between Main/Engine PWB - Operation panel PWB
• Remedy: Connection of the wires and connectors between the main/engine PWB - the operation panel PWB. If the connector is not inserted enough, reinsert it. Or check the wire's continuity and replace the wire if there is no continuity.
  Operation panel PWB Replace the operation panel PWB. (TSI: see page 4-138, LCD: see page 4- 141)
  Main/Engine PWB Replace the main/engine PWB.

• Code: F010
• Description: Main/Engine PWB Checksum error
• Remedy: Main/Engine PWB Unplug the power cord from the wall outlet, and wait five seconds. Then plug in the power cord and then turn on the power switch. If not corrected, replace the main/ engine PWB.

• Code: F020
• Description: Main/engine PWB RAM checksum error
• Remedy: Main/engine PWB memory (RAM) Turn the power switch off and on If not corrected, replace the main/ engine PWB.
  Expansion memory (DIMM) Replace the expansion memory (DIMM)

• Code: F040
• Description: Main/engine PWB engine communication error
• Remedy: Main/Engine PWB Turn the power switch off and on If not repaired, replace the EEPROM on the main/engine PWB or main/engine PWB.

• Code: F041
• Description: Main/engine PWB - Scanner PWB communication error
• Remedy: Main/Engine PWB Turn the power switch off and on If not corrected, replace the main/ engine PWB.