• Code: SC544
• Description: Hot roller fusing lamp–low temperature reading - Timing - Checked every second after warm-up is complete. - Condition - The hot roller thermistor output is higher than 3V (87°C) for 8 seconds in a row.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board • Defective AC drive board
• Remedy: 1. Make sure the fusing unit is installed properly. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the thermistor’s resistance. If it is open, replace it. (Refer to the attached Temperature/ Resistance Conversion Reference Table.) 5. Test the main control board, I/O control board, or AC drive board by checking output from the thermistor and the trigger signal at each pin. [Signal Check] • Thermistor: CN214-A4, TP234, or CN211- B1 on the I/O control board/CN302-B9 or TP117 on the main control board. • Hot roller fusing trigger: CN303-B6 on the main control board/CN212-B6, TP248, or CN229-5 on the I/O control board/CN7-6 on the AC drive board.

• Code: SC545
• Description: Abnormal hot roller ready temperature - Timing - Checked every second after the ready temperature is reached. - Condition - If the temperature drops below the ready temperature and does not rise again within 7 minutes.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board • Defective AC drive board
• Remedy: 1. Make sure the fusing unit is installed properly. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the thermistor’s resistance. If it is open, replace it. (Refer to the attached Temperature/ Resistance Conversion Reference Table.) 5. Test the main control board, I/O control board, or AC drive board by checking output from the thermistor and the trigger signal at each pin. [Signal Check] • Thermistor: CN214-A4, TP234, or CN211- B1 on the I/O control board/CN302-B9 or TP117 on the main control board. • Hot roller fusing trigger: CN303-B6 on the main control board/CN212-B6, TP248, or CN229-5 on the I/O control board/CN7-6 on the AC drive board.

• Code: SC547
• Description: Hot roller temperature does not increase - Timing - Checked every second, starting two minutes after the main switch is turned on and ending when the hot roller reaches the ready temperature. - Condition - Over one minute, the fusing roller temperature does not increase by more than 3°C.
• Causes: Poor connections • Blown hot roller fusing lamp • Opened hot roller thermofuse • Defective main control board • Defective I/O control board • Defective AC drive board
• Remedy: 1. Make sure the following are connected properly: • Hot roller fusing lamp • CN303 on the main control board • CN212 and CN229 on the I/O control board • CN7 on the AC drive board 2. Replace the hot roller fusing lamp if it is blown. 3. Replace the hot roller thermofuse if it is opened. 4. Test the main control board, I/O control board, or AC drive board by checking the trigger signal at each pin. [Signal Check] • Hot roller fusing trigger: CN303-B6 on the main control board/CN212-B6, TP248, or CN229-5 on the I/O control board/CN7-6 on the AC drive board.

• Code: SC551
• Description: Pressure roller thermistor open - Timing - Checked every second when the fusing unit is installed. - Condition - The pressure roller thermistor output is approximately 5V (0°C) for 6 seconds in a row.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board
• Remedy: 1. Make sure the fusing unit is properly installed. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the thermistor’s resistance. If it is open, replace it. (Refer to the attached Temperature/Resistance Conversion Reference Table.) 5. Replace the I/O control board. 6. Replace the main control board. [Signal Check] • Thermistor: CN214-A9, TP232, or CN211- B2 on the I/O control board/CN302-B8 or TP118 on the main control board.

• Code: SC552
• Description: Pressure roller warm-up error - Timing & Condition - The pressure roller thermistor does not register the ready temperature within 12 minutes of turning on the main switch.
• Causes: • Poor connections • Blown pressure roller fusing lamp • Pressure roller thermofuse opened • Blown fuse • Power fluctuation • Defective main control board • Defective I/O control board • Defective AC drive board
• Remedy: 1. Make sure the following are connected properly: • Pressure roller fusing lamp • CN303 on the main control board • CN212 and CN229 on the I/O control board • CN7 on the AC drive board 2. Replace the hot roller fusing lamp if it is blown. 3. Replace the hot roller thermofuse if it is opened. 4. Check for power fluctuations from the outlet. 5. Test the main control board, I/O control board, or AC drive board by checking the trigger signal at each pin. [Signal Check] • Pressure roller fusing trigger: CN303-B7 on the main control board/CN212-B5, TP240, or CN229-4 on the I/O control board/CN7-7 on the AC drive board

• Code: SC553
• Description: Overheating pressure roller - Timing - Checked every second when the fusing unit is installed. - Condition - The pressure roller thermistor output is lower than 0.3V (220°C) for 3 seconds in a row.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board • Defective AC drive board
• Remedy: 1. Make sure the fusing unit is properly installed. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the resistance across the thermistor. If it is open, replace it. (Refer to the attached Temperature/Resistance Conversion Reference Table.) 5. Test the main control board, I/O control board, or AC drive board by checking the output from the thermistor and the trigger signal at each pin. [Signal Check] • Thermistor: CN214-A9, TP232, or CN211- B2 on the I/O control board/CN302-B8 or TP118 on the main control board. • Pressure roller fusing trigger: CN303-B7 on the main control board/CN212-B5, TP240, or CN229-4 on the I/O control board/CN7-7 on the AC drive board.

• Code: SC554
• Description: Pressure roller– low temperature readings - Timing - Checked every second after the warm-up is completed - Condition - The pressure roller thermistor output is higher than 3V (87°C) for 8 seconds in a row.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board • Defective AC drive board
• Remedy: 1. Make sure the fusing unit is properly installed. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the resistance across the thermistor. If it is open, replace it. (Refer to the attached Temperature/Resistance Conversion Reference Table.) 5. Test the main control board, I/O control board, or AC drive board by checking the output from the thermistor and the trigger signal at each pin. [Signal Check] • Thermistor: CN214-A9, TP232, or CN211- B2 on the I/O control board/CN302-B8 or TP118 on the main control board. • Pressure roller fusing trigger: CN303-B7 on the main control board/CN212-B5, TP240, or CN229-4 on the I/O control board/CN7-7 on the AC drive board.

• Code: SC555
• Description: Abnormal pressure roller ready temperature - Timing - Checked every second after the temperature reaches the ready condition - Condition - The pressure roller thermistor output does not reach the ready temperature within 7 minutes.
• Causes: • Fusing unit not installed properly • Poor connections • Defective thermistor • Defective I/O control board • Defective main control board • Defective AC drive board
• Remedy: 1. Make sure the fusing unit is properly installed. 2. Make sure the thermistor is properly connected. 3. Replace the thermistor if it is deformed. 4. Measure the resistance across the thermistor. If it is open, replace it. (Refer to the attached Temperature/Resistance Conversion Reference Table.) 5. Test the main control board, I/O control board, or AC drive board by checking the output from the thermistor and the trigger signal at each pin. [Signal Check] • Thermistor: CN214-A9, TP232, or CN211- B2 on the I/O control board/CN302-B8 or TP118 on the main control board. • Pressure roller fusing trigger: CN303-B7 on the main control board/CN212-B5, TP240, or CN229-4 on the I/O control board/CN7-7 on the AC drive board.