• Code: 549
• Description: Fusing-temperature range violation (too low)
  During paper transport, fusing temperature fell below lower limit (155°C) and remained below limit for 6 seconds.
• Causes: • Fusing thermistor defective • PSU defective

• Code: 550
• Description: Standby temperature error 1
  Fusing temperature failed to drop to expected level within a given time (15 seconds, 15 minutes, or 25 minutes, depending on mode) after entering standby or low-power mode.
• Causes: • TRIAC short • Fan not running

• Code: 551
• Description: Standby overheat
  Temperature during standby or low-power mode remained too high for a specified interval (10 seconds or 25 seconds, depending on the mode).
• Causes: • TRIAC short

• Code: 552
• Description: Standby low temperature error
  After reaching expected temperature in low-power mode (level 1) or standby mode, temperature fell and remained below 155°C for 20 seconds.
• Causes: • Fusing thermistor defective • PSU defective

• Code: 692
• Description: Communication error between FCU and printer controller
  Printer failed to acknowledge message from FCU within 1.2 seconds.
• Causes: • Printer controller defective • FCU defective • Poor connection between FCU and printer controller

• Code: 900
• Description: Electrical total counter error
  The electrical total counter is not working properly.
• Causes: • SRAM defective. The only way to correct this error is to replace the FCU.

• Code: 901
• Description: Mechanical total counter
  The mechanical total counter is not working properly.
• Causes: • Mechanical total counter disconnected