Description: Fusing temperature warm-up error
During fusing warm-up, fusing temperature failed to reach target range within 22 seconds (when starting at least 25°C below the target temperature).
Causes: • Fusing thermistor defective • Fusing lamp defective • Thermofuse blown • PSU defective • Bad connection between fuser and machine
Code: 543
Description: Fusing overheat error
Detected fusing temperature remained above 230°C for 1 second.
Description: Fusing low temperature error
Detected fusing temperature remained abnormally low for 1 second during fusing operation (below 140°C) or during standby mode.
Causes: • Fusing thermistor defective • PSU defective • Bad connection between fuser and machine
Code: 546
Description: Unstable fusing temperatureDetected that fusing temperature changed more than +-25°C/second two seconds in succession.
Causes: • Fusing thermistor defective • PSU defective • Bad connection between fuser and machine
Code: 547
Description: Zero-cross detection error
Detection error (detection overflow or busy) occurred 8 times in succession (at 20-ms intervals) while 24V power was on.
Causes: • PSU defective • FCU defective
Code: 548
Description: Fusing-temperature range violation (too high)
During paper transport, fusing temperature moved above limit (200°C for plain paper, 210°C for thick paper) and remained above limit for 10 seconds.