Samsung ML-451 Series Service Manual page 212

4. Alignment and Troubleshooting
► Error Code
U1–2320
U1–2330
► Error message
Fuser Unit Failure #U1-2320 : Turn off then on.
Fuser Unit Failure #U1-2330 : Turn off then on.
► Symptom
Fuser Open heat error or Low heat error has occurred.
► Troubleshooting method
1) After checking the fuser installation, turn the machine off then on.
2) Open the rear cover. Lift up the right side and release the rear cover.
3) If there is no problem, remove 4 screws.
4) Lift up the both levers. Then take off the fuser unit.
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