Oki ML490 Maintenance Manual page 5

3.3.20 Rear Tractor Assy ................................................................................................. 77
3.3.21 Rear Pressure Assy .............................................................................................. 78
3.3.22 Switch Lever ......................................................................................................... 79
4. ADJUSTMENT ...................................................................................................80
5. CLEANING AND LUBRICATION .......................................................................88
5.1 Cleaning ............................................................................................................................. 88
5.2 Lubrication ......................................................................................................................... 89
6. TROUBLESHOOTING AND REPAIR ................................................................97
6.1 Items to Check Before Repair ............................................................................................ 97
6.2 Troubleshooting Table ....................................................................................................... 97
6.3 Lamp Display ..................................................................................................................... 98
6.4 Connection Circuit Check for Printhead and SP/LF Motor............................................... 102
6.5 Troubleshooting flow chart ............................................................................................... 104
APPENDIX A PCB LAYOUT ...............................................................................116
APPENDIX B SPARE PARTS LIST ....................................................................117
APPENDIX C RS-232C SERIAL INTERFACE BOARD (OPTION) ....................128
1. GENERAL ............................................................................................................................ 128
2. OPERATION DESCRIPTION .............................................................................................. 128
2.1 Element Description .................................................................................................. 128
2.2 Circuit Description ..................................................................................................... 129
2.2.1 Operation at power on .................................................................................... 129
2.2.2. RS-232C interface .......................................................................................... 129
2.3 Communication Procedure Flowchart ....................................................................... 130
2.3.1 Mode a .......................................................................................................... 130
2.3.2 Mode b .......................................................................................................... 131
3. TROUBLESHOOTING FLOWCHART ................................................................................. 132
3.1 Before Repairing a Fault ............................................................................................ 132
3.2 Troubleshooting ......................................................................................................... 132
3.3 Local Test .................................................................................................................. 135
3.3.1 Circuit test mode ............................................................................................ 135
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