• Code: 510
• Description: LCT tray malfunction
  1) One of the following has occurred: 2) The LCT lift sensor does not activate for more than 18 seconds after the LCT lift motor turned on. 3) The LCT lower limit sensor does not activate for more than 18 seconds after the LCT lift motor turned on. 4) The LCT lift sensor is already activated when the LCT lift motor turns on. 5) After the paper end sensor is actuated while the tray is raising, the upper limit sensor is not actuated within 5 s. A message is displayed to remind the user to set the paper and tray control halts. Resetting the display is done by opening and closing the LCT door. 6) The 4) state has been detected 3 times in succession.
• Causes: • LCT lift motor defective or disconnected. • Upper limit sensor defective or disconnected • Pick-up solenoid defective or disconnected • Paper end sensor defective

• Code: 520
• Description: Fusing/Feed-Out Motor Error
  The PLL lock signal remains LOW for 2 s while the feed development motor is operating.
• Causes: • Motor lock caused by overload. • Motor driver defective.

• Code: 541
• Description: Fusing thermistor open
  The fusing temperature detected by the thermistor was below 7°C (44.6F) for 5 seconds, or 2 seconds after reaching 45C (113F) the temperature does not reach an additional 15C (59F) after checking five times at 0.1 intervals.
• Causes: • Fusing thermistor disconnected • Fusing thermistor connector defective • Fusing thermistor damaged or warped • Fusing temperature –15% less than the standard input voltage

• Code: 542
• Description: Fusing temperature warm-up error
  The fusing temperature does not reach the fusing standby temperature of 45C (113F) within 9 seconds [for the B003/B006 (35 cpm)]/14 seconds [for the B004/B007 (45 cpm)] after switching on the main power or closing the front cover, or 40 seconds after reaching 50C the fusing roller does not reach warm-up temperature.
• Causes: • Fusing lamp defective • Poor fusing unit connector • Thermistor warped or broken • Thermostat has tripped • BICU defective • Power supply board defective

• Code: 543
• Description: Fusing overheat error (software detection)
  A fusing temperature of over 230°C (446F) is detected for 5 seconds by the fusing thermistors at the center or at either end of the fusing roller.
• Causes: • Power supply unit defective • I/O board (IOB) defective • BICU defective • Fusing thermistor defective

• Code: 544
• Description: Fusing overheat error (hardware circuit detection)
  The dual monitoring circuitry of the BICU detects extremely high temperature and tripped the relay circuit off.
• Causes: • Power supply unit defective • I/O board (IOB) defective • BICU defective • Fusing thermistor defective

• Code: 545
• Description: Fusing lamp remains on
  After warm-up the fusing lamp remains at full power for 10 seconds without the hot roller rotating.
• Causes: • Thermistor is out of position.

• Code: 546
• Description: Fusing ready temperature unstable
  The fusing temperature is fluctuating.
• Causes: • Thermistor connection loose • Fusing unit connector loose