Oki Data CONFIDENTIAL43967002TH Rev. 1 340 /7. Troubleshooting7.5.2.(11) Fuser unit error (error 170 to 177)(11-1) Jam occurs immediately after the power is turned on.Check item Check work Action to be taken at NG(11-1-1) Thermistor is defective note)Upper thermistor,lower thermistor,frame thermistorCheck the respective thermistors if they areshorted or opened internally.Check the resistance value at theconnector pins in the bottom of the fuserunit. (Refer to item 8.1 Resistance check(fuser unit).)Replace thefuser unit. If anyattempt of usingnew fuser unit asa trial is going tobe made, be sureto use the SystemMaintenance MenuFUSE KEEP MODE.Installed conditionof fuser unit.Check if the fuser nit is pressed in until theconnector in the bottom of the fuser unit issurely connected.Re-set the fuserunit.Note) Service calls 171 error and 171 error can occur when the printer temperatureis below 0 degree C. Turn on the power again after the printer temperature hasincreased.(11-2) Error occurs approx. 1 minutes after the power is turned on.Check item Check work Action to be taken at NG(11-2-1) Temperature increase of fuser unitThermostat,halogen lampIf the fuser unit temperature does notincrease and remains cold, check that theresistance between pin-1 and pin-2, andthat in between pin-3 and pin-4 of the twoconnectors is in the range of several ohmsto several ten ohms respectively. (Refer toitem 8.1 Resistance value (fuser unit).)Replace thefuser unit. If anyattempt of usingnew fuser unit asa trial is going tobe made, be sureto use the SystemMaintenance MenuFUSE KEEP MODE.Check item Check work Action to be taken at NG(11-2-2) Temperature increase of fuser unitInstallation positionof the upperthermistorCheck if the upper thermistor is installed inthe far position from the specified positionor not causing detection of the lowertemperature than the actual temperatureof fuser unit. Remove the heater cover,and check warpage of sensor by visualinspection.Replace thefuser unit. If anyattempt of usingnew fuser unit asa trial is going tobe made, be sureto use the SystemMaintenance MenuFUSE KEEP MODE.Installation positionof the lowerthermistorThe lower thermistor must be installedwhile contacting with the fuser unit. Checkif the lower thermistor is installed in the farposition from the specified position or notcausing detection of the lower temperaturethan the actual temperature of fuser unit.Replace thefuser unit. If anyattempt of usingnew fuser unit asa trial is going tobe made, be sureto use the SystemMaintenance MenuFUSE KEEP MODE.(11-2-3) AC power input to the halogen lampAC power voltagefrom the low voltagepower supplyCheck if the AC voltage for heater isnormally supplied or not. Power supplyCN2 connector , between pin-1 andpin-2, and between pin-3 and pin-4.Replace the lowvoltage powersupply unit.Heater ON signalthat is outputfrom PU to thelow voltage powersupplyCheck that the heater ON signal goesactive at the warming up timing, or not.“L” active while ON. POWER connectorpins-11 and -12 of the PU PCB.Replace the PUPCB.
