44072903TH Rev.1 169 /Oki Data CONFIDENTIAL 7. TROUBLESHOOTING PROCEFRURES7.5.2.(1) LCD Display MalfunctionMemo For numbers of (1) through (26) after each connector name, refer to 7.5.2 (18)"Connection Diagrams".(1-1) Nothing is displayed in LCDConfirmation Items Confirmation Tasks Action at NG(1-1-1) Confirm fuseF5 (fuse) of PU PCB Check to see if F5 is blown out. Replace F5 orPU PCB.(1-1-2) Confirm connection systemsConnection betweenlow voltage powersupply unit and PUPCBCheck to see if the cord from the low-voltagepower supply is connected properly to thePOWER connector ⑩ of the PU PCB. Check forany incomplete connection or skew insertion.Redo theinsertion of thecord properlyCord ASSYinterconnecting thelow-voltage powersupply unit and thePU PCBCheck to see if the cord has any wire breakage.Check to see if the cord has any peel-off of thecovering. Check for any fault in the cord ASSY,such as dislocated wire, etc.Replace thecord with anormal one.Connectionbetween PU PCBand operator panelPCB (PRP PCB)Check to see if the 7pin FFC is properly pluggedinto theOPE connector ⑰ of the PU PCB. Check to seeif the 7pin FFC is properly plugged into the CNconnector ⑲ of the operator panel PCB (PRPPCB). Check for any incomplete connection orskew insertion.Redo theinsertion of thecord properly.FFC interconnectingthe PU PCB and theoperator panel PCB(PRP PCB).Check for wire breakage with a circuit-tester.Also, check visually for peel-off of the covering.Replace theFFC with anormal one.FFC interconnectingthe PU PCB and theCU PCB.Check to see if the 12pin FFC is properlyplugged into the CUIF connector ⑨ of the PUPCB. Check similarly the CU PCB side also.Replace the lowvoltage powerSupply.Confirmation Items Confirmation Tasks Action at NG(1-1-3) Confirm the power systemsAC power suppliedto the printerCheck the supply voltage of the AC power. Supply ACpower.Voltage setting oflow voltage powersupply unit (100Vsystem/230Vsystem)Measure the supplied AC voltage. Check thepower supply settings of the printer in use.(Check the shortcircuit plug designed forswitching of low-voltage power setting. Short-circuit plug provided/not provided = 100Vsystem/230V system.)Set the low-voltage powersetting to theproper values.5V power suppliedto the PU PCBCheck the 5V power at pin 7 of the POWERconnector ⑩ of the PU PCB.Replace the lowvoltage powersupply.5V power suppliedto the operatorpanel PCB (PRPPCB)Check the 5V power at pin 5 of the CNconnector of the operator panel PCB (PRPPCB).Replace the F5or PU PCB.(1-1-4) Confirm the power short5V power and 24Vpower supplied tothe PU PCBCheck for short-circuiting through the POWERconnector ⑩ of the PU PCB.4, 5, 6 pin: 24V7 pin: 5V8 pin: 0VL1, 2, 3 pin: 0VPIf there is any short-circuiting, locate it byisolation.Unplug the cords connected to the PU PCB,one by one, and locate the short-circuited part.Replace theshort circuitedpart.
