Ricoh SP C440dn, Field Service Manual, Page: 594 / 654

No. Type Details (Symptom, Possible Cause, Troubleshooting Procedures)
554 A Heating roller fusing lamp overheat 2 (hardware error)
The heating roller thermistor (end) detects 250°C or more.
• Defective heating roller thermistor (end)
• Defective PSU
• Defective BCU
• Defective fusing control system
1. Replace the heating roller thermistor (end).
2. Replace the PSU.
3. Replace the BCU.
No. Type Details (Symptom, Possible Cause, Troubleshooting Procedures)
555 A Heating roller lamp consecutive full power 2
When the fusing unit is not running in the ready condition, the pressure roller-
fusing lamp keeps ON full power for 8 seconds or more.
• Broken heating roller thermostat
• Broken heating roller fusing lamp
1. Replace the heating roller thermostat.
2. Replace the heating roller fusing lamp.
No. Type Details (Symptom, Possible Cause, Troubleshooting Procedures)
557 C Zero cross frequency error
When the zero cross signal is 66 or more and it is detected 10 times or more in
11 detections, the machine determines that input 60 Hz and SC557 occurs.
Noise (High frequency)
Check the power supply source.
6. Troubleshooting
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