• Code: 551-02
• Description: Thermistor (edge) disconnection: Low voltage • An error is detected only when the input voltage at power-on is low. • Temperature of 0°C or lower is detected for 25 seconds continuously. Detection time: 10 or more Detection interval: 0.1 seconds
• Causes: • Thermistor (edge) disconnection • Thermistor (edge) not connected correctly
• Remedy: • Reconnect the thermistor (edge). • Replace the thermistor (edge). • Clear this SC by executing SP5-810-001.

• Code: 553-00
• Description: Thermistor (edge) high temperature detection: Software • Temperature above 230°C is detected for 1 second continuously. • Detection with the thermistor (edge) Detection time: 10 or more Measurement interval: 0.1 sec
• Causes: • Triac short-circuit • MPU defective
• Remedy: • Replace the MPU. • Clear this SC by executing SP5-810-001.

• Code: 554-00
• Description: Thermistor (edge) high temperature detection: Hardware Temperature of 250°C or higher is detected by the thermistor (edge).
• Causes: • Triac short-circuit • MPU defective • Fusing control error
• Remedy: • Replace the MPU. • Clear this SC by executing SP5-810-001.

• Code: 557-00
• Description: Zero cross frequency exceeded When low frequency is detected once, this SC is issued.
• Causes: Power line noise
• Remedy: Turn the power off and on.

• Code: 559-00
• Description: Fusing jam SC. A fusing jam, which does not reach the paper exit sensor, is detected three times consecutively. • If paper exits normally (passes the paper exit sensor), the count will be cleared. • This detection is effective only when the setting of SP1-159-001 (Fusing jam 3 times SC setting) is set to “1 (on)”. (Default: 0 (off)) • The fusing jam counter value is retained after turning the power off/on. • The fusing jam counter (internal counter) is reset when the setting of SP1-159-001 is changed from "1" to "0". • The fusing jam counter is reset when clearing this SC after SC559-00 has been issued.
• Causes: Paper winding around the fusing roller.
• Remedy: • Replace the fusing unit. • Clear this SC by executing SP5-810-001.

• Code: 622-00
• Description: 2nd tray communication error • An error occurs during the line connection between the mainframe and the optional PFU (2nd tray). • A communication error report is received between the mainframe and the optional PFU (2nd tray) is received.
• Causes: • The 2nd paper tray's main board defective • MPU defective • 2nd tray and the machine are not connected correctly.
• Remedy: • Reconnect the 2nd tray connection cable. • Replace MPU. • Replace the 2nd tray.

• Code: 623-00
• Description: 3rd tray communication error • An error occurs during the line connection between the mainframe and the optional PFU (3rd tray). • A communication error report is received between the mainframe and the optional PFU (3rd tray).
• Causes: • 2nd tray main board defective • 3rd tray main board defective • 2nd tray and 3rd tray not connected correctly
• Remedy: • Reconnect the 2nd tray and 3rd tray connection cable. • Replace the 3rd tray.

• Code: 669-01
• Description: EEPROM communication error – Access-type designation error
• Causes: When the machine retries three times after an error report has been received in the EEPROM communication, but the machine does not recover the communication, this SC is issued. • Noise • EEPROM not connected • EEPROM mounted in reverse • EEPROM defective
• Remedy: EEPROM not connected: • Reinstall the EEPROM on the MPU. EEPROM mounted in reverse: • Mount the EEPROM correctly on the MPU. EEPROM defective: • Replace the EEPROM on the MPU.