2JN1-4-106030 Broken fuser thermistor wireInput from fuser thermistor is 0 (A/Dvalue).Poor contact in thefuser thermistorconnector termi-nals.Reinsert the connector (See page 1-5-34).Broken fuser ther-mistor wire.Replace the fuser unit (See page 1-5-34).Fuser thermistorinstalled incor-rectly.Replace the fuser unit (See page 1-5-34).Fuser thermal cut-out triggered.Replace the fuser unit (See page 1-5-34).Fuser heater lampinstalled incor-rectly.Replace the fuser unit (See page 1-5-34).Broken fuserheater lamp wire.Replace the fuser unit (See page 1-5-34).6400 Zero cross signal errorThe zero cross signal does not reach thecontrol PWB for specified time.Defective harnessbetween high volt-age PWB (YC202)and control PWB(YC23), orimproper connec-tor insertion.Reinsert the connector. Also check for conti-nuity within the connector harness. If none,remedy or replace the harness (See page 1-5-39).Defective connec-tion betweenpower source PWB(YC103) and highvoltage PWB(YC201).Reinsert the connector.Defective powersource PWB.Replace the power source PWB (See page1-5-42).Defective controlPWB.Replace the control PWB (See page 1-5-39).7990 Waste toner fullThe waste toner sensor has detectedthat the waste toner reservoir (drum unit)is full.Waste toner reser-voir (drum unit) isfull.Turn the main power switch off/on to restartthe machine. If the error is not resolved,replace the drum unit (See page 1-5-30).Defective wastetoner sensor.Replace the waste toner sensor.Defective controlPWB.Replace the control PWB (See page 1-5-39).F000 Control PWB - Operation panel PWBcommunication errorDefective harnessbetween operationpanel PWB (YC1)and control PWB(YC7), or improperconnector inser-tion.Reinsert the connector. Also check for conti-nuity within the connector harness. If none,remedy or replace the harness.Defective opera-tion panel PWB.Replace the operation panel PWB.Defective controlPWB.Replace the control PWB (See page 1-5-39).Code Contents RemarksCauses Check procedures/corrective measuresService Manual Y111030-4