• Code: SC545
• Description: Hot roller ready temperature abnormal - Timing - Every 1 second after the temperature reaches the ready condition - Condition - The hot roller thermistor output does not reach the ready temperature within 7 minutes.
• 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: SC547
• Description: Hot roller temperature does not increase - Timing - Every 1 second, 2 minutes after the main switch turned on until the hot roller temperature reaches the ready condition - Condition - The hot roller temperature does not increase by more than 3 °C for a minute during warm-up.
• Causes: • Poor connection of connectors • Hot roller fusing lamp blown • Hot roller thermofuse opened • Defective main control board • Defective I/O control board • Defective PSU
• 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. Replace the main control board, I/O control board, or AC drive board (check the trigger signal at each pin). - 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: SC551
• Description: Pressure roller thermistor open - Timing - Every 1 second after the fusing unit is installed - Condition - The pressure roller thermistor output is almost close to 5V, which corresponds to 0 °C, for 6 seconds continuously.
• Causes: • Fusing unit not installed 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 installed. 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 I/O control board. 6. Replace the main control board. - Signals to Check - • Thermistor: CN206-B4, TP230, or CN214-B2 on I/O control board / CN302-B8 or TP156 on main control board.

• Code: SC552
• Description: Pressure roller warm-up error - Timing & Condition - The pressure 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 • Pressure roller fusing lamp blown • Pressure roller thermofuse opened • Blown fuse • Power fluctuation • Defective main control board • Defective I/O control board • Defective PSU
• Remedy: 1. Check if the following connectors are properly connected; • Pressure 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 pressure roller fusing lamp if it is opened. 3. Replace the pressure 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). - Signals to Check - • Pressure roller fusing lamp trigger: CN303-B7 on main control board / CN218-B5, TP267, or CN205-A5 on I/O control board / CN106-4 on PSU.

• Code: SC553
• Description: Pressure roller overheat - Timing - Every 1 second when the fusing unit is installed - Condition - The pressure roller thermistor output is lower than about 0.3V, which corresponds to 220 °C, for 3 seconds continuously.
• Causes: • Fusing unit not installed 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 installed. 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-B4, TP230, or CN214-B2 on I/O control board / CN302-B8 or TP156 on main control board. • Pressure roller fusing trigger: CN303-B7 on main control board / CN218-B5, TP267, or CN205-A5 on I/O control board /CN106-4 on PSU.

• Code: SC554
• Description: Pressure roller low limit temperature detected - Timing - Every 1 second after warm-up is completed - Condition - The pressure roller thermistor output is higher than about 3 V, which corresponds to 87 °C, for 8 seconds continuously after warm-up is completed.
• Causes: • Fusing unit not installed 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 installed. 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-B4, TP230, or CN214-B2 on I/O control board / CN302-B8 or TP156 on main control board. • Pressure roller fusing trigger: CN303-B7 on main control board / CN218-B5, TP267, or CN205-A5 on I/O control board /CN106-4 on PSU.

• Code: SC555
• Description: Pressure roller ready temperature abnormal - Timing - Every 1 second after the temperature reaches the ready condition - Condition - The pressure roller thermistor output does not reach the ready temperature within 7 minutes continuously.
• Causes: • Fusing unit not installed 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 installed. 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-B4, TP230, or CN214-B2 on I/O control board / CN302-B8 or TP156 on main control board. • Pressure roller fusing trigger: CN303-B7 on main control board / CN218-B5, TP267, or CN205-A5 on I/O control board /CN106-4 on PSU.

• Code: SC557
• Description: Pressure roller temperature does not increase - Timing - Every 1 second, 2 minutes after the main switch turned on until the roller temperature reaches the ready condition - Condition - The pressure roller temperature does not increase by more than 3 °C for a minute during warm-up.
• Causes: • Poor connection of connectors • Pressure roller fusing lamp brown • Pressure roller thermofuse opened • Defective main control board • Defective I/O control board
• Remedy: 1. Check if the following connectors are properly connected: • Pressure roller fusing lamp connectors • CN303 on the main control board • CN206 and CN214 on the I/O control board 2. Replace the pressure roller fusing lamp if it is opened. 3. Replace the pressure roller thermofuse if it is opened. 4. Replace the main control board, I/O control board, or by checking the trigger signal at each pin. - Signals to Check - • Pressure roller fusing trigger: CN303-B7 on main control board / CN218-B5, or CN205-A5 on I/O control board.