• Code: 504
• Description: 4th tray lift malfunction (optional paper tray unit)
  The paper height sensor is not activated after the tray lift motor has been on for 13 seconds. Note: Normally, if the power switch is turned on when the paper is already at the feed height, the paper height position is detected again. At this time, the paper height sensor should de-activate within 5 seconds after the paper bottom plate starts to drop. If it does not deactivate within 5 s after four attempts, the tray lift motor halts. After two attempts to re-set the paper tray, if this does not solve the problem, then this SC is displayed and tray control halts.
• Causes: • Lift motor connector or harness loose, broken, defective. • Lift motor defective • Height sensor connector or harness loose, broken, defective • Height sensor defective

• Code: 506
• Description: Paper tray unit motor lock (optional paper tray)
  A main motor lock was detected for more than 50 ms during rotation of the motor in either the 3rd or 4th tray of the optional paper feed unit.
• Causes: • Paper tray unit main motor connector or harness loose, broken, defective • Motor overload due to an obstruction • Motor defective

• Code: 507
• Description: LCT main motor lock
  A main motor lock signal was detected for more than 50 ms during rotation if the LCT motor.
• Causes: • LCT main motor connector or harness loose, broken, defective • Motor overload due to an obstruction • LCT main motor defective

• Code: 510
• Description: LCT tray malfunction
  One of the following has occurred: 1. The LCT lift sensor did not activate within 18 sec. after the LCT lift motor turned on. 2. The LCT lower limit sensor did not activate within 18 sec. after the LCT lift motor turned on. 3. The LCT lift sensor was already activated when the LCT lift motor turned on. 4. After the paper end sensor was actuated while the tray was being raised, the upper limit sensor did not actuate within 2.5 sec. In this case, a message is displayed to remind the user to set the paper and tray control halts. The display is reset by opening and closing the LCT door. 5. This SC code is issued if problem "4" occurs 3 times.
• Causes: • LCT lift motor connector or harness loose, broken, or defective, or LCT lift motor defective • Upper limit sensor connector or harness loose, broken, or defective, or sensor is defective. • Pick-up solenoid connector or harness loose, broken, or defective or solenoid is defective • Paper end sensor connector or harness loose, broken, or defective, or sensor is 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 overload due to an obstruction • Motor drive board defective.

• Code: 541
• Description: Fusing thermistor open
  After the hot roller center thermistor temperature reached 45C (113F), the center fusing temperature failed to reach 60C (140oF) within 2 sec. for 5 counts at 0.1 sec. intervals. -or- After the hot roller end temperature thermistor reached 45oC (113F), the end fusing temperature failed to reach 57C (135F) within 2 sec. for 5 counts at 0.1 sec. intervals.
• Causes: • Fusing thermistor disconnected • Fusing thermistor connector defective • Fusing thermistor damaged, warped, or out of position • Input voltage less than 15% of the standard input voltage

• Code: 542
• Description: Fusing temperature warm-up error
  The fusing temperature did not reach the fusing reload temperature of 45C (113F) within 26 sec.
• Causes: • Fusing lamp connector or harnesses loose, broken or defective • Poor fusing unit drawer connector loose • Thermistor warped, broken, or out of position • Thermostat has tripped • PSU defective • BICU defective

• Code: 543
• Description: Fusing overheat error (software detection)
  A fusing temperature of over 230C (446F) is detected for 5 seconds by the fusing thermistors at the center or at either end of the hot roller.
• Causes: • Check harnesses and connectors of PSU, IOB, BICU • PSU defective • IOB defective • BICU defective • Fusing thermistor defective or wrong type