• Code: SC541
• Description: Fusing thermistor open
  The fusing temperature detected by the thermistor was below 13C (55.4F) 60 times within one 1 s.
• Causes: • Fusing thermistor defective • Thermistor cable disconnected, broken

• Code: SC542
• Description: Fusing temperature warm-up error
  After switching on the machine, or after opening and closing the machine, during warmup the hot roller did not attain the ready temperature within 5 minutes (the temperature was detected below 2C 5 times within 5 s).
• Causes: • Fusing lamp defective • Fusing thermistor defective • Thermistor floating, out of position • Thermistor cable disconnected, broken

• Code: SC543
• Description: Fusing overheat error 1 (software)
  A fusing temperature of over 215 C (419F) was detected for 5 s
• Causes: • IOB board defective • BCU board defective • PSU defective • TRIAC short

• Code: SC544
• Description: Fusing overheat error 2 (hardware)
  The BCU backup circuit detects an overheat error even if the software overheat protection does not work.
• Causes: • TRIAC short • IOB board defective • BCU board defective • PSU board defective

• Code: SC545
• Description: Fusing lamp overheat error 3
  After reaching the ready temperature, the hot roller does not start to rotate and the fusing lamp stays on at full power for 60 s.
• Causes: • Hot roller thermistor not positioned correctly • Fusing lamp defective • Thermostat defective

• Code: SC546
• Description: Unstable fusing temperature
  Fusing temperature is rapidly fluctuating more than 20°C (68°F) at 1 s intervals. -or-Fusing temperature fluctuating over a long period. It fluctuates 20°C (68°F) more than 3 times during 60 s interval.
• Causes: • Poor thermistor connection

• Code: SC547
• Description: Zero-cross signal malfunction
  One of the following conditions has occurred: • Abnormal mains frequency was detected more than 10 times. • No zero-cross signal detected for 3 s while the relay is on. • No zero-cross signal detected for 3.5 s after the main switch is turned on.
• Causes: • Electrical noise on the power line. • PSU defective.

• Code: SC549
• Description: Pressure roller thermistor abnormal
  During fusing motor rotation, pressure roller temperature detected lower than 7°C (44.6°F) for 5 s.
• Causes: • Thermistor shorted, disconnected, or its connector is damaged.