MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN
SERVICE MANUAL
iii
3.2.2 For Parallel Interface Cable Users
(For Windows
®
95/98/98SE/Me/2000 Professional/XP) ................................................... 2-13
3.2.3 For Windows NT
®
Workstation Version 4.0 Users ............................................................ 2-18
3.2.4 For Network Interface Cable Users
(For Windows
®
95/98/98SE/Me/NT/2000 Professional/XP) .............................................. 2-20
3.2.5 For USB Interface Cable Users (For Mac
®
OS 8.6 to 9.2 Users) ...................................... 2-23
3.2.6 For USB Interface Cable Users (For Mac
®
OS X 10.1/10.2.1 or greater Users) ............... 2-24
3.2.7 For Network Interface Cable Users (For Mac
®
OS 8.6 to 9.2 Users) ................................ 2-25
3.2.8 For Network Interface Cable Users (For Mac
®
OS X 10.1/10.2.1 or greater Users) ......... 2-26
CHAPTER 3 THEORY OF OPERATION................................................. 3-1
1. ELECTRONICS ...................................................................................................... 3-1
1.1 General Block Diagram .................................................................................................... 3-1
1.2 Main PCB Block Diagram ................................................................................................. 3-2
1.3 Main
PCB ......................................................................................................................... 3-3
1.3.1 CPU..................................................................................................................................... 3-3
1.3.2 USB ..................................................................................................................................... 3-3
1.3.3 IEEE
1284 ........................................................................................................................... 3-4
1.3.4 ROM .................................................................................................................................... 3-4
1.3.5 Flash
ROM .......................................................................................................................... 3-5
1.3.6 SDRAM ............................................................................................................................... 3-5
1.3.7 Optional
RAM ...................................................................................................................... 3-6
1.3.8 EEPROM............................................................................................................................. 3-7
1.3.9 Reset
circuit ........................................................................................................................ 3-7
1.3.10 Engine I/O ........................................................................................................................... 3-7
1.3.11 Panel I/O ............................................................................................................................. 3-7
1.3.12 Video I/O ............................................................................................................................. 3-8
1.3.13 Scanner control ................................................................................................................... 3-8
1.3.14 Power supply....................................................................................................................... 3-9
1.4 Engine
PCB .................................................................................................................... 3-10
1.5 Power
Supply.................................................................................................................. 3-11
1.5.1 Low-voltage power supply.................................................................................................3-11
1.5.2 High-voltage power supply ................................................................................................3-12
2. MECHANICS ........................................................................................................ 3-13
2.1 Overview of Printing Mechanism .................................................................................... 3-13
2.2 Scanner
Mechanism....................................................................................................... 3-14
2.3 Paper
Transfer ............................................................................................................... 3-15
2.3.1 Paper
supply ..................................................................................................................... 3-15
2.3.2 Paper
registration .............................................................................................................. 3-15
2.3.3 Paper
eject ........................................................................................................................ 3-16
2.3.4 Duplex
printing .................................................................................................................. 3-16
2.4 Sensors .......................................................................................................................... 3-17
2.4.1 Cover
sensors ................................................................................................................... 3-17
2.4.2 Toner
sensors ................................................................................................................... 3-17
2.4.3 Cassette sensor / Paper empty sensor ............................................................................. 3-18
2.4.4 Paper eject sensor ............................................................................................................ 3-18
2.4.5 MP-PE
sensor ................................................................................................................... 3-19
2.4.6 Document cover sensor ....................................................................................................3-19
2.4.7 Document front sensor / Document rear sensor ............................................................... 3-20
2.4.8 DX-sensor PCB ASSY.......................................................................................................3-20
Summary of Contents for DCP-8020
Page 264: ...CHAPTER 7 MAINTENANCE MODE 7 6 Fig 7 3 l m a b c d e f g h i j k ...
Page 335: ...APPENDIX 4 CIRCUIT DIAGRAMS A 50 Appendix 4 1 Main PCB Circuit Diagram 1 6 ...
Page 337: ...APPENDIX 4 CIRCUIT DIAGRAMS A 52 Appendix 4 3 Main PCB Circuit Diagram 3 6 ...
Page 339: ...APPENDIX 4 CIRCUIT DIAGRAMS A 54 Appendix 4 5 Main PCB Circuit Diagram 5 6 ...
Page 341: ...APPENDIX 4 CIRCUIT DIAGRAMS A 56 Appendix 4 7 Driver PCB Circuit Diagram ...
Page 343: ...APPENDIX 4 CIRCUIT DIAGRAMS A 58 Appendix 4 9 Engine PCB Circuit Diagram 2 2 ...
Page 345: ...APPENDIX 4 CIRCUIT DIAGRAMS A 60 Appendix 4 11 NCU PCB Circuit Diagram Europe ...
Page 347: ...APPENDIX 4 CIRCUIT DIAGRAMS A 62 Appendix 4 13 NCU PCB Circuit Diagram Oceania ...