Oki C711DW Maintenance Manual - Page 151

Oki Data CONFIDENTIAL 7. Troubleshooting and repair procedure 7.5.2. (1) LCD display error Memo For the numbers from through after name of the respective connectors, refer to section 7.5.2 (19) "Wiring diagram". (1-1) LCD does not display anything. Check item (1-1-1) Check the fuse. Check work Action to be taken at NG F3,F5 (fuse) of the CU/PU board Check if F3,F5 has blown out or not. R eplace CU/PU board. (1-1-2) Check the system connection Connection between the low voltage power supply unit and the CU/PU board. Check if the cable from the low voltage power supply to the POWER connector of the CU/ PU board is normally connected or not. Check if the connector is connected only in the half-way or not, and check if the connector is inserted in slanted angle or not. Re-connect the cable normally. Cable assembly connecting the low voltage power supply unit and the CU/PU board. Check if the cable is half-open circuit. Check if sheath of the cable has not peeled off or not. Check if the cable assembly is defective such as internal wires are disconnected or not. Replace the cable with the normal cable. Note! Connection between the CU/PU board and Operator Panel Check if the 11-conductor FFC is connected to the OPE connector of the CU/PU board normally or not. Check if the 11-conductor FFC is connected to the OPE connector of the CU/PU board normally or not. Check if the connector is connected in the halfway only or not, and check if the connector is inserted in a slanted angle or not. Re-connect the cable normally. FFC connecting the CU/PU board and the Operator Panel board Check if the cable has open circuit or not with VOM. Check if sheath of the cable has not peeled off or not by visual inspection. Replace the FFC with the normal FFC. Check item Check work Action to be taken at NG (1-1-3) Check the peripherals of the power supplies Primary AC power source that is connected to the printer. Check the supplied voltage of the AC power source. Supply the AC power. Voltage setting of the lower voltage power supply unit (100V system/230V system) Measure the AC voltage supplied. Check the power voltage setting of the equipment in use. (Check the shorting plug that is used for selection of the voltage power supplies.) Shorting plug is Used/Not used = 100V system/ 230V system. S et the low voltage power supply setting. 5V power that is supplied to the CU/ PU board. C heck for the 5V power supply at pin-1, 2, 3 of the POWER connector of the CU/PU board. Replace the low voltage power supply. 3.3V power that is supplied to the Operator Panel. Check for the 3.3V power supply at pin-11 of the CN connector of the Operator Panel board. Replace F2 or the CU/PU board. (1-1-4) Check that power supply circuit has no short-circuit. 5V power and 24V power that are supplied to the CU/ PU board. Check that power supply circuit has no shortcircuit at the POWER connector no. 10 of the CU/PU board. The follow voltage must appear respectively. pins-7, 8 and 9: 24V pin-1, 2 and 3: 5V pin-4, 5 and 6: 0VL pins-10, 11 and 12: 0VP If any voltage does not appear and short-circuit is detected, locate the source of the short-circuit as follows: Disconnect the cables that are connected to the CU/PU board one cable after another until location of the short-circuit is found out. Replace the part causing shortcircuit. 44205401TH Rev.1 151 /