• Code: SC504
• Description: 4th paper tray error - Timing & Condition - • The upper limit sensor does not turn on1.5 s after the tray bottom plate starts to go up.
• Causes: • Defective upper limit sensor • Defective tray bottom plate • Defective I/O control board • Defective main control board
• Remedy: 1. Check if the spring of pick-up solenoid comes off. 2. Check if the sensor cable is properly connected. 3. Clean or replace the sensor and replace it if necessary (Input Check: SP 5-803-14 to 17). 4. Replace the tray bottom lever if it is broken. 5. Pull out the paper tray and check if the tray lift motor works properly (Output Check: SP 5-804-75 to 82). 6. Replace the I/O control board. 7. Replace the main control board. - Signals to Check - • Limit sensor H.P.: CN226-2 or TP206 on I/O control board

• Code: SC510
• Description: Paper feed motor error - Timing & Condition - • The feedback signal from the motor is still out of range 1 second after the trigger signal is sent. • The feedback signal becomes out of range for 2 seconds while the trigger signal is on
• Causes: • Poor connection of connector • Defective paper feed motor • Defective I/O control board • Defective main control board • Mechanical overload
• Remedy: 1. Check if the connector is properly connected on the I/O control board (CN224). 2. Replace the paper feed motor. (Output check: SP 5- 804-08 to 09) 3. Replace the I/O control board. 4. Replace the main control board. 5. Check the feed unit drive section and if anything causes overload. - Signals to Check - • Motor OK: CN224-B4 or TP297 on I/O control board

• Code: SC522
• Description: Duplex - Side fence jogger H.P. error - Timing & Condition - • The home position is still detected a few seconds after the side fence leaves from the home position. • The home position is not detected 12 seconds after the side fence moves back to the home position.
• Causes: • Duplex unit not set properly • Excessive load • Poor connection of connector • Defective side fence motor • Defective I/O control board
• Remedy: 1. Pull out and re-insert the duplex unit. 2. Check the connector (CN485) is properly connected on the duplex control board. 3. Check if anything causes overload to the motor. 4. Replace the side fence motor (Output Check: SP 5-804 93 and 94). 5. Replace the I/O control board

• Code: SC524
• Description: Duplex - End fence jogger H.P. error - Timing & Condition - • The home position is still detected a few seconds after the end fence leaves from the home position. • The home position is not detected 13 seconds after the end fence moves back to the home position.
• Causes: • Duplex unit not set properly • Excessive load • Poor connection of connector • Defective end fence motor • Defective I/O control board
• Remedy: 1. Pull out and re-insert the duplex unit. 2. Check the connector (CN486) is properly connected on the duplex control board. 3. Check if anything causes overload to the motor. 4. Replace the end fence motor (Output Check: SP 5-804 95 and 96). 5. Replace the I/O control board.

• Code: SC541
• Description: Hot roller thermistor open - Timing - Every 1 second when the fusing unit is installed - Condition - The hot roller thermistor output is almost close to 5V, which corresponds to 0 °C, for 6 seconds continuously.
• Causes: • Fusing unit not set properly • Poor connection of connector • Defective thermistor • Defective I/O control board • Defective main control board
• Remedy: 1. Check if the fusing unit is properly set. 2. Check if the thermistor connector is properly connected. 3. Replace the thermistor if it is deformed. 4. Replace the thermistor if it is opened by measuring the resistance. (Refer to the Temperature/ Resistance Conversion Reference Table at the end of this table.) 5. Replace the I/O control board. 6. Replace the main control board. - Signals to Check - • Thermistor: CN206-B9, TP231, or CN214-B1 on I/O control board / CN302-B9 or TP154 on main control board.

• Code: SC542
• Description: Hot roller warm-up error - Timing & Condition - The hot roller thermistor does not output an analog value corresponding to the ready temperature within 12 minutes after the main switch is turned on.
• Causes: • Poor connection of connectors • Hot roller fusing lamp blown • Hot roller thermofuse opened • Power fluctuation • Defective main control board • Defective I/O control board • Defective AC drive board
• Remedy: 1. Check if the following connectors are properly connected: • Hot roller fusing lamp connectors • CN303 on the main control board • CN206 and CN214 on the I/O control board • CN105 on the PSU 2. Replace the hot roller fusing lamp if it is opened. 3. Replace the hot roller thermofuse if it is opened. 4. Check if the power supplied from the outlet fluctuates. 5. Replace the main control board, I/O control board, or PSU (check the trigger signal at each pin and replace any defective boards). - Signals to Check - • Hot roller fusing lamp trigger: CN303-B6 on main control board / CN205-A4, TP267, or CN218-B6 on I/O control board / CN106-5 on PSU.

• Code: SC543
• Description: Hot roller fusing lamp overheat - Timing - Every 1 second when the fusing unit is installed - Condition - The hot roller thermistor output is lower than about 0.3V, which corresponds to 220 °C, for 3 seconds continuously.
• Causes: • Fusing unit not set properly • Poor connection of connector • Defective thermistor • Defective I/O control board • Defective main control board • Defective PSU
• Remedy: 1. Check if the fusing unit is properly instaled. 2. Check if the thermistor connector is properly connected. 3. Replace the thermistor if it is deformed. 4. Replace the thermistor if it is opened by measuring the resistance. (Refer to the Temperature/ Resistance Conversion Reference Table at the end of this SC code table.) 5. Replace the main control board, I/O control board, or PSU (check the output from the thermistor and the trigger signal at each pin). - Signals to Check - • Thermistor: CN206-B9, TP231, or CN214-B1 on I/O control board / CN302-B9 or TP154 on main control board. • Hot roller fusing trigger: CN303-B6 on main control board / CN205-A4, TP267, or CN218-B6 on I/O control board / CN106-5 on PSU.

• Code: SC544
• Description: Hot roller fusing lamp lower limit temperature detected - Timing - Every 1 second after warm-up is completed - Condition - The hot roller thermistor output is higher than about 3V, which corresponds to 87 °C, for 8 seconds continuously after warm-up is completed.
• Causes: • Fusing unit not set properly • Poor connection of connector • Defective thermistor • Defective I/O control board • Defective main control board • Defective PSU
• Remedy: 1. Check if the fusing unit is properly instaled. 2. Check if the thermistor connector is properly connected. 3. Replace the thermistor if it is deformed. 4. Replace the thermistor if it is opened by measuring the resistance. (Refer to the Temperature/ Resistance Conversion Reference Table at the end of this SC code table.) 5. Replace the main control board, I/O control board, or PSU (check the output from the thermistor and the trigger signal at each pin). - Signals to Check - • Thermistor: CN206-B9, TP231, or CN214-B1 on I/O control board / CN302-B9 or TP154 on main control board. • Hot roller fusing trigger: CN303-B6 on main control board / CN205-A4, TP267, or CN218-B6 on I/O control board / CN106-5 on PSU.