Oki Data CONFIDENTIAL43967002TH Rev. 1 317 /7. Troubleshooting7.5.2.(1) LCD display errorMemo For the numbers from through after name of the respective connectors,refer to 7.5.2.(19) “Wiring diagram”.(1-1) LCD does not display anything.Check item Check work Action to be taken at NG(1-1-1) Check the fuseF2, F3 and F4(fuses) on MZAPCBCheck if F2 or F3 or F4 has blown out ornot.Replacement of F2,F3, F4 or MZA PCB.(1-1-2) Check the system connectionConnection betweenthe low voltagepower supply unitand the MZA PCBCheck if the cable from the low voltagepower supply to the POWER connectorof the MZA PCB is normally connected ornot. Check if the connector is connected inthe half-way only or not, and check if theconnector is inserted in a slanted angle ornot.Re-connect thecable normally.Cable assemblyconnecting thelow voltage powersupply unit and theMZA PCBCheck if any open-circuit or peeling-offof sheath has occurred or not throughoutthe cable. Check if the cable assemblyis defective such as internal wires aredisconnected or not.Replace the cablewith the normalcable.Power supply toMAZ PCB andscannerCheck that cable is connected normallyto the SCPOW connector of MZA PCB.Check for secure coupling of connectors.Re-connect thecable normally.FFC connecting thePU PCB and the CUPCBCheck that 12-conductor FFC is connectedto the CUIF connector of the P PCB.Check the CU PCB side in the samemanner.Replace the lowvoltage powersupply.Check item Check work Action to be taken at NG(1-1-3) Check the peripherals of the power suppliesPrimary AC powersource that isconnected to theprinter.Check the supplied voltage of the ACpower source.Supply the ACpower.Voltage setting ofthe lower voltagepower supply unit(100V system/230Vsystem)Measure the AC voltage supplied.Check the power voltage setting of theequipment in use.(Check the shorting plug that is used forselection of the voltage power supplies.)Shorting plug is Used/Not used = 100Vsystem/230V system.Set the low voltagepower supplysetting.5V power that issupplied to the MZAPCB.Check 5V power at pin-1 and 24V power atpin-6 of the POWER connector of MZAPCB.Replace the lowvoltage powersupply.5V power that issupplied to thescannerCheck 24V power at pin-1, and 5V powerat pin-5 of the CN connector of A PCB.Replace F5 or theP6X PCB.(1-1-4) Check that power supply circuit has no short-circuit.5V or 24V powersupply that issupplied to the PUPCBCheck that power supply circuit has noshort-circuit at the POWER connector pinof the POWER PCB.Pin-4, -5, -6: 24VPin-7: 5VPin-8: 0VLPin-1, -2, -3: 0VPIf any voltage does not appear and short-circuit is detected, locate the source ofthe short-circuit as follows. Disconnect thecables that are connected to the PU PCBone cable after another until location of theshort-circuit is found out.Replace the partcausing short-circuit.
