Warning: SP 5-810 resets counters. If you only want to clear the SC code without resetting PM (Preventive Maintenance) counters, use SP 7-403 (SC Code Reset) instead.
Remove finisher rear and upper covers to access:
Clean sensor with soft brush + air. Re-seat connector. sc569-00 ricoh
The thermistor is a small, glass-encapsulated resistor that changes resistance with temperature. Over time, toner dust and paper dust create an insulating layer on the thermistor. This layer delays temperature readings, confusing the zero-cross detection circuit.
SC569-00 is a specific service call code related to the fusing unit (also known as the fuser). In technical terms, it indicates a "Zero Cross Error of the Fusing Thermistor." Warning: SP 5-810 resets counters
To translate: The printer’s central processing unit (CPU) monitors the AC power supply to the fusing lamp. The "zero cross" refers to the point where the AC voltage waveform crosses zero volts. When the fusing thermistor (a temperature sensor) fails to detect the correct zero cross signal or detects an abnormal frequency, the printer instantly halts operation and displays SC569-00.
Note: While extremely similar to SC568 (Thermistor break) and SC570 (Fusing lamp overheating), SC569 specifically points to a signal timing or detection failure within the fusing heating circuit. Clean sensor with soft brush + air
Prevention is cheaper than repair. Follow these best practices: