CONTENTSAPPENDIX A PC Board Description and OperationPageA1.1 Unit Configuration and Block Diagram ......................................... A1-1OKIFAX5750/5950 Block Diagram (1) ........................................................ A1-3OKIFAX5750/5950 Block Diagram (2) ........................................................ A1-4A2.1 OKIFAX5750/5950 Signal Flow ...................................................... A2-1A2.2 Explanation of Signal Flowchart ................................................... A2-21A3.1 MCNT ............................................................................................... A3-1A3.1.1 CPU ............................................................................................................. A3-1A3.1.1.1 Functions ............................................................................................................... A3-1A3.1.2 IOGA5 ......................................................................................................... A3-3A3.1.2.1 Purpose and Overview of This ASIC ...................................................................... A3-3A3.1.3 Scanner Control .......................................................................................... A3-5A3.1.3.1 Overview ................................................................................................................ A3-5A3.1.4 JBIG Control ................................................................................................ A3-8A3.1.4.1 Overview ................................................................................................................ A3-8A3.1.4.2 Code conversion .................................................................................................... A3-8A3.1.4.3 CPU access ........................................................................................................... A3-8A3.1.5 Scanner Motor Control ................................................................................ A3-11A3.1.6 CPU Peripheral Circuits .............................................................................. A3-12A3.1.6.1 Memory .................................................................................................................. A3-12A3.1.6.2 Peripheral elements ............................................................................................... A3-12A3.1.6.3 Backup circuit ......................................................................................................... A3-13A3.1.6.4 Fan control ............................................................................................................. A3-14A3.1.7 LED Head Control ....................................................................................... A3-15A3.1.8 Heater Control ............................................................................................. A3-17A3.1.9 Printer Motor Control ................................................................................... A3-18A3.1.10 Toner Low Detection ................................................................................... A3-20A3.1.11 Centronics Parallel Interface ....................................................................... A3-22A3.1.12 Electrophotographic Process ...................................................................... A3-23A3.1.12.1 Process Operation Descriptions ............................................................................. A3-26A3.2 OPE Control .................................................................................... A3-36A3.3 MODEM C34 PC Board ................................................................... A3-37A3.4 UNC, WN5, FN5 and DN5 Circuit Diagram .................................... A3-42A3.5 Power Supply Board ....................................................................... A3-55A3.6 High-voltage Power Supply Circuit ............................................... A3-57A3.7 G4A-PCB.......................................................................................... A3-59A3.8 G3A-PCB.......................................................................................... A3-61
