Oki Data CONFIDENTIAL43085101TH Rev.1 179 /7.5.2.(1) LCD Display Malfunction(1-1)Nothing is displayed in LCDF5 (fuse) of PU PCB(PRXPCB)Connection between low-voltage power supply unit andPU PCB (PRX PCB)Cord ASSY interconnectingthe low-voltage power supplyunit and the PU PCB (PRXPCB)Connection between PUPCB(PRX PCB) and operatorpanel PCB(PRP PCB)FFC interconnecting the PUPCB (PRX PCB) and theoperator panel PCB (PRPPCB).FFC interconnecting the PUPCB (PRX PCB) and the CUPCB.AC power supplied to theprinterVoltage setting of low-voltagepower supply unit (100Vsystem/230V system)5V power supplied to the PUPCB (PRX PCB)5V power supplied to theoperator panel PCB (PRP PCB)5V power and 24V powersupplied to the PU PCB (PRNPCB)Confirmation TasksCheck to see if F5 is blown out.Check to see if the cord from the low-voltage power supply isconnected properly to the POWER connector of the PUPCB(PRX PCB). Check for any incomplete connection or skewinsertion.Check to see if the cord has any wire breakage.Check to see if the cord has any peel-off of the covering.Check for any fault in the cord ASSY, such as dislocated wire,etc.Check to see if the 7pin FFC is properly plugged into the OPEconnector of the PU PCB(PRX PCB). Check to see if the 7pinFFC is properly plugged into the CN connector of the operatorpanel PCB (PRP PCB). Check for any incomplete connection orskew insertion.Check for wire breakage with a circuit-tester. Also, checkvisually for peel-off of the covering.Check to see if the 12pin FFC is properly plugged into the CUIFconnector of the PU PCB (PRP PCB). Check similarly the CUPCB side also.Check the supply voltage of the AC power.Measure the supplied AC voltage. Check the power supplysettings of the printer in use.(Check the short-circuit plugdesigned for switching of low-voltage power setting. Short-circuitplug provided/not provided = 100V system/230V system.)Check the 5V power at pin 7 of the POWER connector of the PUPCB (PRX PCB).Check the 5V power at pin 4 of the CN connector of the operatorpanel PCB (PRP PCB)..Check for short-circuiting through the POWER connector of thePU PCB.4, 5, 6 pin: 24V7 pin: 5V8 pin: 0VL1, 2, 3 pin: 0VPIf there is any short-circuiting, locate it by isolation.Unplug the cords connected to the PU PCB (PRX PCB), one byone, and locate the short-circuited part.Action at NGReplace F5 or PRXPCB.Redo the insertion ofthe cord properly.Replace the cord with anormal one.Redo the insertion ofthe cord properly.Replace the FFC with anormal one.Replace the low-voltage power supply.Supply AC power.Set the low-voltagepower setting to theproper values.Replace the low-voltage power supply.Replace the F5 or PRXPCB.Replace the short-circuited part.Confirmation Items(1-1-1)Confirm fuse(1-1-2)Confirm connection systems(1-1-3)Confirm the power systems(1-1-4)Confirm the power short
