• Code: 508
• Description: By-pass bottom plate error
  The signal from the by-pass tray HP sensor does not change for 1.0 second after the by-pass motor has rotated counterclockwise. If this condition occurs three consecutive times, the SC is generated.
• Causes: • Disconnect or defective harness of the by-pass motor • Defective or disconnected connection for the by-pass motor. • Defective by-pass motor • Disconnect or defective harness of the by-pass HP sensor • Defective or disconnected connection for the by-pass HP sensor. • Defective by-pass HP sensor
• Remedy: Check the operation of the by-pass motor with SP5804-023. No operation: 1. Check the harness connection of the by-pass tray and duplex unit. 2. Replace the by-pass motor. Operation: Check the operation of the by-pass HP sensor with SP5803-048 while the by-pass motor is rotating. No change of Bit 0 1. Check the harness connection of the by-pass HP sensor. 2. Replace the by-pass HP sensor.

• Code: 530
• Description: Ventilation fan: front error
  The motor lock signal error is detected for 10 seconds after the motor lock signal was first detected.
• Causes: • Defective ventilation fan: front or rear • Disconnected or defective harness • Defective DRB • Defective BCU
• Remedy: 1. Check or replace the harness. 2. Replace the ventilation fan: front (SC530) or rear (SC531). 3. Replace the DRB. 4. Replace the BCU.

• Code: 531
• Description: Ventilation fan: rear error
  The motor lock signal error is detected for 10 seconds after the motor lock signal was first detected.
• Causes: • Defective ventilation fan: front or rear • Disconnected or defective harness • Defective DRB • Defective BCU
• Remedy: 1. Check or replace the harness. 2. Replace the ventilation fan: front (SC530) or rear (SC531). 3. Replace the DRB. 4. Replace the BCU.

• Code: 532
• Description: Laser unit fan error
  The motor lock signal error is detected for 10 seconds after the motor lock signal was first detected.
• Causes: • Defective laser unit fan • Disconnected or defective harness • Defective drive board • Defective BCU
• Remedy: 1. Replace the laser unit fan. 2. Check the harness of the laser unit fan. 3. Replace the harness of the laser unit fan. 4. Replace the drive board. 5. Replace the BCU.

• Code: 541
• Description: Fusing thermistor open (center)
  The temperature of the hot roller remained below 0C for 5 sec at the center of the hot roller.
• Causes: • Fusing thermistor out of its position because of incorrect installation • Fusing thermistor disconnected or defective • Power supply not within rated range (15% or more below rating)
• Remedy: 1. Check the fusing thermistor is set correctly. 2. Replace the fusing thermistor. 3. Check the power supply source.

• Code: 542
• Description: Fusing temperature warm-up error (center)
  • The fusing temperature did not reach the standby temperature within 20 sec. at the center of the hot roller after the main switch turned on.
• Causes: • Fusing thermistor defective or out of position • Fusing lamp disconnected • Thermistor defective • Fusing lamp defective
• Remedy: 1. Check the fusing thermistor is set correctly. 2. Replace the fusing thermistor. 3. Check the fusing lamp is connected. 4. Replace the fusing lamp.

• Code: 543
• Description: Fusing overheat error 1 (center)
  The fusing thermistor detected a fusing temperature over 230°C for 5 sec. at the center of the hot roller.
• Causes: • TRIAC short on PSU (PSU defective) • BCU board defective • Fusing thermistor defective
• Remedy: 1. Replace the PSU. 2. Replace the BCU board. 3. Replace the thermistor.

• Code: 544
• Description: Fusing overheat error 2 (center)
  A fusing temperature over 250°C is detected at the center of the hot roller by the fusing temperature monitor circuit in the BCU board. The power was interrupted for more than 0.3 sec.
• Causes: • TRIAC short on PSU (PSU defective) • BCU board defective • Fusing thermistor defective • Power supply voltage unstable
• Remedy: 1. Replace the PSU. 2. Replace the BCU board. 3. Replace the thermistor. 4. Check the power supply source.