44072903TH Rev.1 191 /Oki Data CONFIDENTIAL 7. TROUBLESHOOTING PROCEFRURES7.5.2.(11) Fuser Unit Error(Error 170-177)(11-1) An error occurs right after turning on the powerConfirmation Items Confirmation Tasks Action at NG(11-1-1) Malfunction of thermistors Note!Upper thermistor,lower thermistor,frame thermistorCheck to see if the thermistors are short-circuited or open.Check the resistance value through theconnector pins below the fuser unit.(See Subsection 8.1 Check of resistance values(Fuser unit.)Replace thefuser unit. Touse a new fuserunit on a trialbasis, use FUSEKEEP MODEof the SystemMaintenanceMenu.Installed state offuser unitCheck to see if the fuser unit is securely pushedin to such a position that the connector at itslower part is plugged in.Redo theinstallation ofthe fuser unit.Note! Error 171 and 175 of Service Call may occur when the device is 0ºC orless, therefore, the power should be turned on after the device temperaturewarmed up.(11-2) An error occurs in 1 min. from turning on the powerConfirmation Items Confirmation Tasks Action at NG(11-2-1) Temperature rise of fuser unitThermostat,halogen lampEnsure that the heater control is properlyexerted, and touch the fuser unit to confirm thatit is hot.If it remains cold, confirm that the resistancebetween pin 1 and pin 6 of the connectors (2)measures from several Ωto several tens of Ω.Replace thefuser unit. Touse a new fuserunit on a trialbasis, use FUSEKEEP MODEof the SystemMaintenanceMenu.(11-2-2) Temperature rise of fuser unitInstalled state ofupper thermistorCheck to see if the upper thermistor is installedaway from its prescribed position, causing thetemperature to be measured low. Detach theheater cover, and check visually for warpage ofthe sensor, etc.Replace thefuser unit. Touse a new fuserunit on a trialbasis, use FUSEKEEP MODEof the SystemMaintenanceMenu.Installed state oflower thermistorCheck to see if the lower thermistor is locatedaway, whereas it should be in contact with theunit, causing a lower temperature than theprescribed one to be detected.Replace thefuser unit. Touse a new fuserunit on a trialbasis, use FUSEKEEP MODEof the SystemMaintenanceMenu.(11-2-3) AC input for halogen lampAC voltage of low-voltage powersupplyCheck to see if the AC voltage for the heater issupplied normally.Between pins 1 and 2 and between pins 3 and4 of the CN2 connector ㉔ of the power supply.Replace the low-voltage powersupply.Heater-on signaldelivered from PU tolow-voltage powersupplyCheck to see if the heater-on signal turns activeat the warming-up timing. "L" active while it isON.Pin 11 and pin 12 of the POWER connector ⑩of the PU PCBReplace the PUPCB.
