Brother T-8420B Service Manual

SERVICE MANUAL MODEL: MFC8420/8820D/8820DN DCP8020/8025D/8025DN Read this manual thoroughly before maintenance work. Keep this manua

REGULATION viii REGULATION LASER SAFETY (110 - 120V MODEL ONLY) This printer is certified as a Class I laser product under the US Department of Health

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-193.7 ADF Unit (1) Remove the document tray ASSY. Fig. 4-30 (2) Disconnect the thre

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-20(4) Remove the two bind B M4x12 Taptite screws, and then remove the document cover. Fig. 4-32 (5) Remov

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-21(8) Remove the document hold ASSY and document hold spring. (9) Remove the two cup

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-22(11) Remove the document ejection tray. Fig. 4-36 (12) Remove the cup B M3x10 Taptite screw, and then re

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-23(14) Disconnect the four connectors. (15) Remove the cup S M3x6 Taptite screw, and th

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-24(19) Remove the cup S M3x6 Taptite screw, and then remove the ADF relay PCB ASSY. (20) Remove the three cup

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-25(23) Remove the ADF film. (24) Remove the B M3x6 Taptite screw, and then remove the s

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-26(28) Remove the conductive bushing, and then remove the LF roller 2 ASSY. (29) Remove the conductive bushin

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-27(33) Remove the film. (34) Remove the document rear sensor, and then disconnect the c

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-283.8 Document Scanner NOTE: The disassembly job of the scanner unit should be done in a clean room to preven

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL ixIEC 825 (220-240V MODEL ONLY) This printer is a Class I laser product as defined in IEC

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-29(5) Remove the six cup B M4x12 Taptite screws, and then remove the top cover ASSY.

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-30(8) Remove the guide shaft from the CCD module. (9) Release the belt from the pulley ASSY. (10) Remove th

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-31(13) Remove the cup B M3x8 Taptite screw, and then remove the FFC plate. (14) Remove

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-32(18) Remove the two pan (S/P washer) M3x6 screws, and then remove the scanning motor FB. Fig. 4-54 (19)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-333.9 Panel Unit (1) Remove the four cup B M4x12 Taptite screws, and then remove the c

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-34(3) Disconnect the three cables. Fig. 4-58 (4) Remove the two cup B M3x8 Taptite screws, and then remo

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-35(5) Remove the backlight holder and the deffusion film. Fig. 4-60 (6) Remove the

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-363.10 Rear Cover C (MFC-8420, DCP-8020 only) (1) Remove the bind B M4x12 Taptite screw, and then remove th

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-373.11 Outer Chute (MFC-8420, DCP-8020 only) (1) Remove the outer chute. Fig. 4-63

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-383.12 Rear Cover MP ASSY / Outer Chute MP ASSY (MFC-8820D/8820DN, DCP-8025D/8025DN only) (1) Remove the re

SAFETY INFORMATION x SAFETY INFORMATION CAUTION FOR LASER PRODUCT (WARNHINWEIS FUR LASER DRUCKER) CAUTION: When the machine during servicing is opera

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-39 (3) Remove the rear cover MP tray. Fig. 4-67 3.13 Rear Cover L/R (1) Remove

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-403.14 Side Cover L/R (1) Remove the three bind B M4x12 Taptite screws, and then remove the side cover R.

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-413.15 Joint Cover (1) Disconnect the three connectors. Fig. 4-71 (2) Remove the fo

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-42(3) Remove the speaker hold spring and the speaker. Fig. 4-73 (4) Remove the four bind B M4x12 Taptit

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-43(5) Remove the two bind B M4x12 Taptite screws, and then remove the joint cover fron

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-44(8) Remove the support flap and the support flap S. Fig. 4-77 Support flap Support flap S

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-453.16 Front Cover ASSY (MFC-8420, DCP-8020 only) (1) Release the link. (2) Remove t

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-463.17 MP Unit (MFC-8820D/8820DN, DCP-8025D/8025DN only) (1) Disconnect the two connectors. (2) Remove the

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-47(7) While pushing the MP pressure plate, remove the separation plate ASSY. Fig. 4-

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-48(8) Remove the shaft of the MP front cover ASSY from the drive release link, and then remove the MP front

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL xiDEFINITIONS OF WARNINGS, CAUTIONS AND NOTES The following conventions are used in this

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-49(10) Remove the MP tray ASSY. Fig. 4-85 (11) Remove the MP tray support flap 2 a

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-50(12) Open the MP chute ASSY cover. (13) Remove the MP-PE actuator. Fig. 4-87 (14) Remove the four bind B

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-51(15) Remove the cup S M3x6 Tite screws, and then remove the MP gear cover. (16) Remov

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-523.19 NCU (MFC-8420/8820D/8820DN only) (1) Disconnect the connector. (2) Remove the two cup S M3x6 Taptit

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-533.20 Fixing Unit (1) Disconnect the heater harness and thermistor harness. (2) Remo

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-54(4) Remove the three cup B M3x10 Taptite screws, and then remove the star wheel holder. Fig. 4-95 (

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-55NOTE: When re-assembling the thermistor to the FU frame upper, ensure the direction o

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-56(10) Remove the two pan (washer) M2.6x6 Taptite screws. (11) Remove the heat roller 25. (12) Remove the hal

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-57(13) Remove the HR bearing 25. (14) Remove the HR gear 34. (15) Remove the HR retaini

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-58• When re-assembling the heat roller 25 to the FU frame upper, ensure you do not damage the heat roller 25

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-1CHAPTER 1 GENERAL 1. OVERVIEW <Front View> Fig. 1-1 <Back View>

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-59(19) Remove the three cleaner spring S. (20) Remove the three cleaner pinch roller AS

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-60(23) Disconnect the connector for the eject sensor harness from the thermistor relay PCB ASSY. (24) Release

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-61NOTE: When re-assembling the paper eject actuator and the eject actuator spring to th

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-623.21 Laser Unit (1) Remove the filter, and then remove the cup S M3x8 Taptite screw and the air duct. Fig

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-63(5) Remove the shutter arm C. Fig. 4-113 Shutter arm C Frame L

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-643.22 Main PCB (1) Disconnect the LD harness 5P. (2) Disconnect the four connectors. Fig. 4-114 Main PCB

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-65(3) Remove the three pan M3x6 screws. (4) Remove the five cup S M3x6 Taptite screws

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-663.23 Base Plate / LV Insulation Sheet (1) Remove the eight bind B M4x12 Taptite screws. (2) Remove the f

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-673.24 DX-Sensor PCB ASSY (MFC-8820D/8820DN, DCP-8025D/8025DN only) (1) Disconnect th

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-683.25 Engine PCB (1) Disconnect the connectors. Fig. 4-119 (2) Remove the two bind B M4x12 Taptite scr

CHAPTER 1 GENERAL 1-2<Inside View (Document Cover Open)> Fig. 1-3 White film Scanner glass Document guidelines Glass strip Scanner lock leve

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-693.26 High-voltage PS PCB ASSY (1) Remove the bind B M4x12 Taptite screw, and then r

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-703.27 Low-voltage PS PCB ASSY (1) Remove the bind B M4x12 Taptite screw. (2) Disconnect the three connect

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-713.28 Paper Feeder (1) Remove the bearing R. (2) Remove the paper pick-up roller ASS

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-72(6) Remove the PE actuator and the CA actuator. Fig. 4-126 (7) Remove the spring, extension P/R from

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-73(10) Remove the bearing L from the P/R shaft. (11) Remove the P/R shaft. Fig. 4-128

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-74(16) Remove the two cup S M3x6 Taptite screws and the four bind B M4x12 Taptite screws. (17) Remove the fro

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-75(21) Remove the hook of the bearing 5, and then slide the feed roller ASSY in the dir

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-76(24) Remove the chute cover. Fig. 4-134 (25) Remove the regist front actuator and regist front actuator

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-77NOTE: When assembling the regist front actuator and the regist rear actuator, set the

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-783.29 Frame L / Drive Unit (1) Remove the main PCB sheet from the frame L. (2) Remove the four bind B M4x

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-32. SPECIFICATIONS 2.1 General Memory Capacity 32 MB Optional Memory 1 DIMM slot; M

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-79(5) Remove the cup S M3x6 Taptite screw. (6) Remove the ground wire. (7) Remove th

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-80(13) Remove the four cup S M3x6 Taptite screws, and then remove the main motor ASSY. Fig. 4-140 (14) Rem

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-81(18) Disconnect the connector from the front cover sensor. (19) Remove the bind B M3x

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-823.30 Reversing Release Solenoid (MFC-8820D/8820DN, DCP-8025D/8025DN only) (1) Remove the two bind B M4x12

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-833.31 Thermistor ASSY (1) Remove the thermistor ASSY. Fig. 4-145 3.32 Fan Motor

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-843.33 Frame R (1) Remove the four bind B M4x12 Taptite screws. (2) Remove the cup S M3x16 Taptite screw. (

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-85(5) Remove the two bind B M4x12 Taptite screws. (6) Remove the cup S M3x6 Taptite s

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-864. PACKING Fig. 4-150 Machine Pad Carton Telephone line cord Pad Drum unit Pad AC power cord Carton C

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-875. GUIDELINES FOR LEAD FREE SOLDER Information on Manually Repairing PCB Solde

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-885. Precautions for hand soldering operations 1) Soldering operations using lead-free solder are basically

CHAPTER 1 GENERAL 1-42.3 Print Media Paper Input <Paper Tray> • Paper type: Plain paper, recycled paper and transparencies, envelopes (Manual

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-896. Soldering irons When soldering is performed manually using lead-free solder, a sol

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-906. SCREW TORQUE LIST 1. Main Body No. Parts code Parts name Location Pcs. Tightening torque N⋅m (Kg

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-914. ADF Unit No. Parts code Parts name Location Pcs. Tightening torque N⋅m (Kgf⋅cm

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-927. LUBRICATION PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4PG4Shaft idle gear 16 Idle gear 16A Shaft idl

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DNSERVICE MANUAL4-93EM3EM3* EM3: Grease EM-D110 3 mm dia. ballDX feed rollerTray feed ZL2Side regist r

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-94 SK4 PG2 * SK4: Grease SK-623 4 mm dia. ball Separation plate ASSY * PG2: Grease PG-662

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-958. HARNESS ROUTING Fan motor 60 unit LVLaser unit (LD harness 5P)Toner sensor PC

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-96Rear cover sensorSpeaker8Panel PCB10FFC / HP sensor / Scanning motor FB911Main PCB12ADF motor / ADF relay

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-1CHAPTER 5 PERIODIC MAINTENANCE To avoid creating secondary problems by mishandlin

CHAPTER 5 PERIODIC MAINTENANCE 5-2<Change Drum message> If the LCD shows the message below, it means the drum unit is near the end of its life.

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-52.5 Fax Compatibility ITU-T Group 3 Coding System MH/MR/MMR/JBIG Modem Speed 33600-240

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-3 (4) Unpack the new drum unit. (5) Put the toner cartridge in the new drum unit u

CHAPTER 5 PERIODIC MAINTENANCE 5-4<Toner Low message> When the toner cartridge is running low, the LCD shows Toner Low. Fig.5-5 If the LCD sho

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-5 (3) Push down the blue lock lever and take the toner cartridge out of the drum unit

CHAPTER 5 PERIODIC MAINTENANCE 5-6 !CAUTION: • Handle the drum unit and toner cartridge carefully. If toner scatters on your hands or clothes, wipe

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-72. PERIODICAL REPLACEMENT PARTS Periodical replacement parts are the parts to be r

CHAPTER 5 PERIODIC MAINTENANCE 5-82.1 Fixing Unit <Replacement procedure> 1) Disconnect the AC cord from the machine. Fig.5-12 2) Close t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-9 3) Remove the DX feed ASSY. Fig.5-14 4) Remove the rear cover MP ASSY. Fig.5-15

CHAPTER 5 PERIODIC MAINTENANCE 5-105) Remove the outer chute MP ASSY. Fig.5-16 6) Remove the two bind B M4x12 Taptite screws, and then remove the

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-118) Remove the two cup S M3x6 Taptite screws, and then remove the NCU unit. Fig.5-18

CHAPTER 5 PERIODIC MAINTENANCE 5-122.2 Paper Feeding Kit <Replacement procedure> 1) Disconnect the AC cord from the machine. Fig.5-20 2) C

CHAPTER 1 GENERAL 1-62.6 Scanner Color/Monochrome Color/Monochrome TWAIN Compliant Yes (Windows® 95/98/98SE/Me/2000 Professional and Windows NT® Work

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-13 3) Remove the pad holder and the separation pad spring from the paper tray. Fig.5

CHAPTER 5 PERIODIC MAINTENANCE 5-143. PERIODICAL CLEANING Clean the following parts periodically to avoid any machine problems or print image def

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-15 Fig.5-25 3.3 Cleaning the Printer !CAUTION: • Do not use isopropyl alcohol to re

CHAPTER 5 PERIODIC MAINTENANCE 5-163.4 Cleaning the Drum Unit When replacing the drum unit or toner cartridge with a new one, be sure to clean the d

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 5-174) Gently wipe the scanner window with a soft dry cloth. Fig. 5-28 5) Re-install

CHAPTER 5 PERIODIC MAINTENANCE 5-184. MTBF / MTTR The meantime between failure (MTBF) and the meantime to repair (MTTR) for this machine are as f

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-1CHAPTER 6 TROUBLESHOOTING 1. INTRODUCTION 1.1 Initial Check (1) Operating envi

CHAPTER 6 TROUBLESHOOTING 6-2(4) Others Condensation: When the machine is moved from a cold room into a warm room in cold weather, condensation may

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-31.3 Identify the Problem If you encounter any machine error or problem, first identif

CHAPTER 6 TROUBLESHOOTING 6-42. ERROR MESSAGE 2.1 Error Message on the LCD If a machine error occurs, the machine emits an audible alarm (continu

© Copyright Brother Industries, Ltd. 2003 All rights reserved. No part of this publication may be reproduced in an

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-72.8 Interfaces Interface Recommended Cable Parallel A bi-directional shielded parallel

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-5 Error Message Cause Action DX Lever Error The paper adjustment lever for duplex pr

CHAPTER 6 TROUBLESHOOTING 6-6 Error Message Cause Action No DX Tray You tried to make duplex printing with duplex cover open. Install the duplex t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-72.2 Error Codes Shown in the “MACHINE ERROR X X” message. If the LCD shows the "

CHAPTER 6 TROUBLESHOOTING 6-8 Error Code (Hex) Error factor Check: 73 Drum unit is not mounted. • Toner sensor • Drum unit 74 Toner empty. • Tone

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-9 Error Code (Hex) Error factor Check: A2 Document too long to scan. A3 Document not

CHAPTER 6 TROUBLESHOOTING 6-10 Error Code (Hex) Error factor Check: F5 Internal software error. • Replace the main PCB if this error occurs frequen

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-113. PAPER PROBLEMS 3.1 Paper Loading Problems First, make sure that you are using

CHAPTER 6 TROUBLESHOOTING 6-123.2 Original Jams Based upon where the original or printed sheet is jammed, follow the appropriate set of instructions

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-133.3 Paper Jams 3.3.1 Clearing jammed paper Clear the jammed paper following the proc

CHAPTER 6 TROUBLESHOOTING 6-14 !CAUTION: To prevent damage to the machine caused by static electricity, do not touch the electrodes shown in Figure 6

CHAPTER 1 GENERAL 1-82.11 Computer Requirements Minimum System Requirements Available Hard Disk Space Computer Platform & Operating System Versio

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-15(6) Open the jam clear cover. Pull the jammed paper out of the fuser unit. Fig. 6-

CHAPTER 6 TROUBLESHOOTING 6-163.3.2 Paper is jammed in the Duplex Tray (For MFC-8820D/8820DN, DCP-8025D/8025DN) (1) Pull the Duplex Tray and paper

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-173.3.3 Causes & countermeasures The causes for paper jam problems vary depending

CHAPTER 6 TROUBLESHOOTING 6-183.4 Paper Feeding Problems Even if the paper is printed and ejected without any problems such as paper jams, paper fee

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-19 F-4 Curl or Wave User Check (1) Check the paper used meets the recommended paper s

CHAPTER 6 TROUBLESHOOTING 6-204. SOFTWARE SETTING PROBLEMS The machine may not print the data correctly if there are incorrect software settings.

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-21 S-3 Although the USB driver is installed, it is unable to find the BRUSB: port. (Wi

CHAPTER 6 TROUBLESHOOTING 6-22 S-4 This machine does not appear in Chooser with iMac and Power Macintosh G3 with USB. User Check (1) Check the mach

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-235. MALFUNCTIONS When taking countermeasures for malfunctions as described in this

CHAPTER 6 TROUBLESHOOTING 6-24 WARNING If you analyze malfunctions with the power plug inserted into the power outlet, special caution should be exer

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-92.12 Paper 2.12.1 Type and size of paper The machine loads paper from the installed p

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-25 M-5 Insufficient output from high-voltage power supply unit Possible cause Step Ch

CHAPTER 6 TROUBLESHOOTING 6-26 M-9 Fixing Unit failure Possible cause Step Check Result Remedy Poor thermistor harness contact 1 Is the contact

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-27 M-12 Engine PCB error Possible cause Step Check Result Remedy Fixing unit ground

CHAPTER 6 TROUBLESHOOTING 6-286. TROUBLESHOOTING OF THE CONTROL PANEL L-1 Nothing is displayed on the LCD. User Check (1) Verify if the power

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-29 L-2 The control panel does not work. User Check (1) No Possible cause Step Check

CHAPTER 6 TROUBLESHOOTING 6-307. TROUBLESHOOTING OF FAX FUNCTIONS F-1 FAX can't send it. User Check (1) Verify that the telephone cord is

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-31 F-2 Speed dialing and One-touch dialing can't be used. Possible cause Step Ch

CHAPTER 6 TROUBLESHOOTING 6-32 F-4 No bell ring. Possible cause Step Check Result Remedy Ring delay 1 Ring delay is set to "0". Yes S

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-33 F-5 Speaker is silent during on-hook dialing. Possible cause Step Check Result Re

CHAPTER 6 TROUBLESHOOTING 6-348. IMAGE DEFECTS 8.1 Image Defect Examples I-2 DarkI-1 Light I-2 Dark I-3 Completely blankI-4 All blackI-5 Dirt on

CHAPTER 1 GENERAL 1-102.12.4 Paper specifications for each paper tray Model MFC-8420 DCP-8020 MFC-8820D/8820DN DCP-8025D/8025DN Multi-purpose tray

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-358.3 Troubleshooting Image Defect Several types of the image defects can be cleared b

CHAPTER 6 TROUBLESHOOTING 6-36 I-2 Dark Possible cause Step Check Result Remedy Ground contacts Corona failure (contact failure) 1 Are the

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-37 I-3 Completely blank Possible cause Step Check Result Remedy Ground contacts De

CHAPTER 6 TROUBLESHOOTING 6-38 I-4 All black Possible cause Step Check Result Remedy Ground contacts Corona failure 1 Is the corona wire dirty

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-39 I-5 Dirt on the back of paper Possible cause Step Check Result Remedy Fixing

CHAPTER 6 TROUBLESHOOTING 6-40 I-6 Black and blurred vertical streaks Possible cause Step Check Result Remedy Dirt on the scanner glass. 1 I

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-41 I-7 Black and blurred horizontal stripes Possible cause Step Check Result Rem

CHAPTER 6 TROUBLESHOOTING 6-42 I-9 White vertical streaks Possible cause Step Check Result Remedy Dirt on the CCD. 1 Is there any dirt on

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-43 I-11 Faulty registration Possible cause Step Check Result Remedy Excessive pape

CHAPTER 6 TROUBLESHOOTING 6-44 I-13 Image distortion Possible cause Step Check Result Remedy Laser unit installation 1 Is the laser unit secure

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-11 !CAUTION: When you are choosing print media, be sure to follow the information given

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-45 I-15 White spots Possible cause Step Check Result Remedy Drum unit failure 1

CHAPTER 6 TROUBLESHOOTING 6-46NOTE: Clean the drum unit as follows: (1) Remove the toner cartridge from the drum unit. Place the printing samples i

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-47 I-16 Black spots Possible cause Step Check Result Remedy Ground contactsDrum

CHAPTER 6 TROUBLESHOOTING 6-48 I-17 Black band Possible cause Step Check Result Remedy Ground contacts Corona failure 1 Is the wire cleaner at

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-49 I-18 Gray background Possible cause Step Check Result Remedy Print paper 1 Do

CHAPTER 6 TROUBLESHOOTING 6-50 I-19 Hollow print Possible cause Step Check Result Remedy Print paper 1 Is thick paper of more than 43lb bei

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-51 I-21 Horizontal lines Possible cause Step Check Result Remedy Ground contacts P

CHAPTER 6 TROUBLESHOOTING 6-52 I-23 Ghost Possible cause Step Check ResultRemedy Driver setting 1 Is thin paper such as 64g/m2 used under

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-538.4 Location of Grounding Contacts 8.4.1 Drum unit Fig. 6-18 8.4.2 Machine bod

CHAPTER 6 TROUBLESHOOTING 6-549. INCORRECT PRINTOUT When the data is not printed correctly as it is seen on the PC screen, follow the procedures b

CHAPTER 1 GENERAL 1-12The table below shows the printable areas when printing on Portrait for each paper size. Size A B C D E F G Letter 215.9 mm

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-55 P-2 Unable to print full pages of a document with the “MEMORY FULL” message. User C

CHAPTER 6 TROUBLESHOOTING 6-5610. NETWORK PROBLEM If the error related to network occurs, refer to the following sections; 10.1 Installation Pr

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-57(3) If you cannot make any of the connections in step (2), check the following: a)

CHAPTER 6 TROUBLESHOOTING 6-5810.3 TCP/IP Troubleshooting If you are using TCP/IP and cannot print to the print server and you have checked the hardw

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-59(7) If PostScript jobs fail to print or are run together, try setting the service (r

CHAPTER 6 TROUBLESHOOTING 6-6010.8 Windows® 95/98/Me/2000/XP/NT 4.0 Peer to Peer Print (NetBIOS) Troubleshooting If you are having trouble printing o

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-6110.11 Novell Netware Troubleshooting If you cannot print from NetWare and you have c

CHAPTER 6 TROUBLESHOOTING 6-6210.12 AppleTalk Troubleshooting In case of using Postscript driver, if you cannot print from an AppleTalk for Macintosh

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 6-6310.15 Internet Fax Troubleshooting (1) If there is a mail delivery error while send

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-1CHAPTER 7 MAINTENANCE MODE 1. ENTRY INTO THE MAINTENANCE MODE To make the mac

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-13

CHAPTER 7 MAINTENANCE MODE 7-22. LIST OF MAINTENANCE–MODE FUNCTIONS Maintenance-mode Functions Function Code Function ReferenceSubsection(Page) 0

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-3< IMPORTANT> Basically, the maintenance-mode functions listed on the previous pa

CHAPTER 7 MAINTENANCE MODE 7-43. DETAILED DESCRIPTION OF MAINTENANCE-MODE FUNCTIONS 3.1 EEPROM Parameter Initialization (Maintenance mode 01/91)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-53.2 Printout of Scanning Compensation Data (Maintenance mode 05) < Function > T

CHAPTER 7 MAINTENANCE MODE 7-6 Fig.7-3 l) m)a) b) c) d) e) f) g) h) i) j) k)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-73.3 Placement of CCD Unit in Position for Transportation (Maintenance mode 06) < F

CHAPTER 7 MAINTENANCE MODE 7-83.5 Test Pattern 1 (Maintenance mode 09) < Function > This function, much like the copying function, prints out

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-93.6 Firmware Switch Setting and Printout 3.6.1 Firmware switch setting (Maintenance

CHAPTER 7 MAINTENANCE MODE 7-10 WSW No. Function WSW35 Function setting 13 WSW36 Function setting 14 WSW37 Function setting 15 WSW38 Function se

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-113.6.2 Printout of firmware switch data (Maintenance mode 11) < Function > The

CHAPTER 1 GENERAL 1-14The table below shows the printable areas when printing on Landscape for each paper size. Size A B C D E F G Letter 279.4 mm

CHAPTER 7 MAINTENANCE MODE 7-123.7 Operation Check of LCD (Maintenance mode 12) < Function > This function allows you to check whether the LCD

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-133.8 Operational Check of Control Panel PCB (Maintenance mode 13) < Function >

CHAPTER 7 MAINTENANCE MODE 7-143.9 Sensor Operational Check (Maintenance mode 32) < Function > This function allows you to check whether the 1

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-15(2) Change the detecting conditions to check that the indication on the LCD changes

CHAPTER 7 MAINTENANCE MODE 7-163.10 Received Data Transfer Function (Maintenance mode 53) (MFC-8420/8820D/8820DN only) < Function > This funct

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-17Example of the cover page ===FAX TRANSFER COVER PAGE===JOB NO.TOTAL PAGE[S]NAMEFAXTEL

CHAPTER 7 MAINTENANCE MODE 7-183.11 Fine Adjustment of Scan Start/End Positions (Maintenance mode 54) < Function > This function is to adjust

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-19MAINTENANCEACCEPTED1. ADF 2. FBSCAN START ADJ.+-+-+-MAINTENANCEMAINTENANCE Fig.7-13

CHAPTER 7 MAINTENANCE MODE 7-203.12 CCD Scanner Area Setting (Maintenance mode 55) < Function > The machine sets the CCD scanner area and stor

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-213.13 EEPROM Customizing (Maintenance mode 74) < Function > This function allow

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-152.14 Print Speeds with Various Settings Print speed of the machine is up to 16/17 pp

CHAPTER 7 MAINTENANCE MODE 7-223.14 Printing out of Machine Log Information (Maintenance mode 77) < Function > This function is to print out l

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-23(1) Loader version (2) Program version and checksum (3) RTC check result and RTC ba

CHAPTER 7 MAINTENANCE MODE 7-243.15 Display of the Equipment’s Log Information (Maintenance mode 80) < Function > The equipment may display it

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-25 USB: USB Serial No. T1_JAM: Number of jams that occurred at the tray 1 T2_JAM Num

CHAPTER 7 MAINTENANCE MODE 7-263.16 Machine Error Code Indication (Maintenance mode 82) < Function > This function displays an error code of t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 7-273.18 Cancellation of the Memory Security Mode (Not applicable to the Japanese versi

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-1 APPENDIX 1 EEPROM CUSTOMIZING CODES This function allows you to customize the EEP

APPENDIX 1 EEPROM CUSTOMIZING CODES A-2< EEPROM Customizing Codes List > Models Versions DCP8020 DCP8025D DCP8025DN MFC8420 MFC8820D MFC8820DNU

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-3APPENDIX 2 INSTALLING THE UPDATE DATA 1. INSTALLING THE UPDATE DATA TO THE MA

APPENDIX 2 INSTALLING THE UPDATE DATA A-41.3 Installing the Update Data onto the Flash ROM of the Machine < On a PC running Windows 95 > (1)

CHAPTER 1 GENERAL 1-163. SERIAL NO. DESCRIPTIONS The descriptions below show how to understand the meanings of the numbers printed on the labels

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-52. SETTING ID CODES TO MACHINES Brother driver machines are assigned unique ID cod

APPENDIX 2 INSTALLING THE UPDATE DATA A-62.3 Running the Setup Utility (1) On your PC, run the ID/head property setup utility (BRUSBSN.EXE). The f

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-7APPENDIX 3 FIRMWARE SWITCHS (WSW) WSW No. Function Reference Page WSW01 Dial p

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-8WSW01 (Dial pulse setting) Selector No. Function Setting and Specifications 1 2 Dial pulse generation mode

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-9l Selector 7: Switching between pulse (DP) and tone (PB) dialing, by the function sw

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-10WSW03 (PABX* mode setting) Selector No. Function Setting and Specifications 1 CNG detection when sharing a mod

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-11WSW05 (1st dial tone and busy tone detection) Selector No. Function Setting and Spec

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-12l Selectors 5 and 6: Busy tone detection in automatic sending mode These selectors determine whether or not t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-13l Selectors 1 through 3: Pause button setting and 2nd dial tone detection Selectors

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-14WSW07 (Dial tone setting 1) Selector No. Function Setting and Specifications 1 2 Frequency band range No. 1

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL iPREFACE This publication is a Service Manual covering the specifications, construction,

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 1-17(4) Toner cartridge: Imprinted on the aluminum bag 3 A 3 0 J Printed

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-15WSW08 (Dial tone setting 2) Selector No. Function Setting and Specifications 1 | 3

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-16WSW09 (Protocol definition 1) Selector No. Function Setting and Specifications 1 Frame length selection 0:

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-17WSW10 (Protocol definition 2) Selector No. Function Setting and Specifications 1 Not

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-18WSW11 (Busy tone setting) Selector No. Function Setting and Specifications 1 2 Frequency band range No. 1 2

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-19WSW12 (Signal detection condition setting) Selector No. Function Setting and Specifi

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-20WSW13 (Modem setting) Selector No. Function Setting and Specifications 1 2 Cable equalizer No. 1 2 0 0 :

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-21WSW14 (AUTO ANS facility setting) Selector No. Function Setting and Specifications

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-22WSW15 (REDIAL facility setting) Selector No. Function Setting and Specifications 1 2 Selection of redial

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-23WSW16 (Function setting 1) Selector No. Function Setting and Specifications 1 Not us

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-24WSW17 (Function setting 2) Selector No. Function Setting and Specifications 1 2 Off-hook alarm No. 1 2 0

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-1CHAPTER 2 INSTALLATION AND BASIC OPERATION 1. CONDITIONS REQUIRED FOR INSTALL

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-25WSW18 (Function setting 3) Selector No. Function Setting and Specifications 1 Not us

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-26WSW19 (Transmission speed setting) Selector No. Function Setting and Specifications 1 | 3 First transmissio

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-27WSW20 (Overseas communications mode setting) Selector No. Function Setting and Speci

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-28WSW21 (TAD setting 1) Selector No. Function Setting and Specifications 1 | 7 Not used. 8 Erasure of message

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-29WSW23 (Communications setting) Selector No. Function Setting and Specifications 1 St

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-30WSW24 (TAD setting 2) Selector No. Function Setting and Specifications 1 2 Not used. 3 4 Time length from CML

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-31WSW26 (Function setting 4) Selector No. Function Setting and Specifications 1 2 Not

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-32WSW27 (Function setting 5) Selector No. Function Setting and Specifications 1 Not used. 2 Ringer OFF settin

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-33WSW28 (Function setting 6) Selector No. Function Setting and Specifications 1 | 3

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-34WSW29 (Function setting 7) Selector No. Function Setting and Specifications 1 | 8 Not used. WSW30 (Function

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-22. UNPACKING When unpacking the machine, check to see that all of the following components are incl

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-35WSW31 (Function setting 9) Selector No. Function Setting and Specifications 1 Not us

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-36WSW32 (Function setting 10) Selector No. Function Setting and Specifications 1 | 4 Not used. 5 6 Default

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-37WSW34 (Function setting 12) Selector No. Function Setting and Specifications 1 | 3 N

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-38WSW36 (Function setting 14) Selector No. Function Setting and Specifications 1 ECP* mode 0: ON 1: OFF 2

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-39WSW37 (Function setting 15) Selector No. Function Setting and Specifications 1 Print

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-40WSW38 (Function setting 16) Selector No. Function Setting and Specifications 1 2 Setting of the equalizer No

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-41WSW39 (Function setting 17) Selector No. Function Setting and Specifications 1 | 4

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-42WSW40 (Function setting 18) Selector No. Function Setting and Specifications 1 Not used. 2 Not used. 3 | 8

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-43WSW41 (Function setting 19) Selector No. Function Setting and Specifications 1 | 3 O

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-44WSW42 (Function setting 20) Selector No. Function Setting and Specifications 1 Incoming mail server POP*1 0:

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-33. INSTALL THE MACHINE You need to implement hardware setup and driver installatio

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-45WSW43 (Function setting 21) Selector No. Function Setting and Specifications 1 Addi

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-46WSW44 (Speeding up scanning-1) Selector No. Function Setting and Specifications 1 | 5 Not used. 6 | 8 Effecti

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-47WSW45 (Speeding up scanning-2) Selector No. Function Setting and Specifications 1 |

APPENDIX 3 FIRMWARE SWITCHS (WSW) A-48WSW46 (Monitor of PC ON/OFF state) Selector No. Function Setting and Specifications 1 2 Monitoring the PC ON/O

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-49WSW48 (Function setting 23) Selector No. Function Setting and Specifications 1 2 Not

APPENDIX 4 CIRCUIT DIAGRAMS A-50Appendix 4.1 Main PCB Circuit Diagram (1/6)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-51Appendix 4.2 Main PCB Circuit Diagram (2/6)

APPENDIX 4 CIRCUIT DIAGRAMS A-52Appendix 4.3 Main PCB Circuit Diagram (3/6)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-53Appendix 4.4 Main PCB Circuit Diagram (4/6)

APPENDIX 4 CIRCUIT DIAGRAMS A-54Appendix 4.5 Main PCB Circuit Diagram (5/6)

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-43.1.1 Install the Automatic Document Feed (ADF) support (1) Open the ADF cover. Fig. 2-2 Fig. 2-3

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-55Appendix 4.6 Main PCB Circuit Diagram (6/6)

APPENDIX 4 CIRCUIT DIAGRAMS A-56Appendix 4.7 Driver PCB Circuit Diagram

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-57Appendix 4.8 Engine PCB Circuit Diagram (1/2)

APPENDIX 4 CIRCUIT DIAGRAMS A-58Appendix 4.9 Engine PCB Circuit Diagram (2/2)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-59Appendix 4.10 NCU PCB Circuit Diagram (U.S.A.)

APPENDIX 4 CIRCUIT DIAGRAMS A-60Appendix 4.11 NCU PCB Circuit Diagram (Europe)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-61Appendix 4.12 NCU PCB Circuit Diagram (Asia)

APPENDIX 4 CIRCUIT DIAGRAMS A-62Appendix 4.13 NCU PCB Circuit Diagram (Oceania)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-63Appendix 4.14 Control Panel PCB Circuit Diagram

APPENDIX 4 CIRCUIT DIAGRAMS A-64Appendix 4.15 Low-voltage Power Supply PCB Circuit Diagram (200V)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-5(3) Close the ADF cover. Fig. 2-5 3.1.2 Install the drum unit assembly (1) Open t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-65Appendix 4.16 Low-voltage Power Supply PCB Circuit Diagram (100V)

APPENDIX 4 CIRCUIT DIAGRAMS A-66Appendix 4.17 High-voltage Power Supply PCB Circuit Diagram (200V)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL A-67Appendix 4.18 High-voltage Power Supply PCB Circuit Diagram (100V)

April. ’03 SM-FAX018 8C5703 Printed in Japan

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-63.1.3 Load paper into the paper tray (1) Pull the paper tray completely out of the machine. (2) Whil

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-73.1.4 Release the scanner lock (1) Push the lever up to unlock the scanner. (Refer

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-83.2 Installing the Driver & Software 3.2.1 For USB Interface Cable Users (For Windows® 98/98SE/Me

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-9(13) When the Brother MFL-Pro Suite Installation window appears, click Next. NOTE: •

TABLE OF CONTENTS ii TABLE OF CONTENTS REGULATION... viii S

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-10< For Windows® 2000 Professional Users Only > Make sure that you followed the instructions in (1

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-11(28) Make sure X:\W2K\Addprt is displayed in the window and click OK (X:\ is the driv

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-12Brother Native driver Installation (20) Click Start and select Printers and Faxes. Click on Add a prin

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-133.2.2 For Parallel Interface Cable Users (For Windows® 95/98/98SE/Me/2000 Profession

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-14(14) When the Brother Software License Agreement window appears, click Yes. (15) Select Local Interfa

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-15(20) Click Finish to restart your computer. (21) After the computer restarts, the in

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-16NOTE: • There will be two Brother printer drivers listed in the Printers selection. • The driver wit

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-17(27) Highlight the model you are installing from the list of machines and click Next

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-183.2.3 For Windows NT® Workstation Version 4.0 Users (1) Turn on your computer. You must be logged on

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-19(15) When the Brother Software License Agreement window appears, click Yes. If you

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL iii3.2.2 For Parallel Interface Cable Users (For Windows® 95/98/98SE/Me/2000 Professiona

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-203.2.4 For Network Interface Cable Users (For Windows® 95/98/98SE/Me/NT/2000 Professional/XP) (1) Con

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-21(14) When the Brother Software License Agreement window appears, click Yes. (15) Sel

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-22(25) After the computer restarts, click Yes to have the Control Center load each time Windows® is sta

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-233.2.5 For USB Interface Cable Users (For Mac® OS 8.6 to 9.2 Users) (1) Switch off a

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-243.2.6 For USB Interface Cable Users (For Mac® OS X 10.1/10.2.1 or greater Users) (1) Switch off and

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 2-253.2.7 For Network Interface Cable Users (For Mac® OS 8.6 to 9.2 Users) (1) Switch o

CHAPTER 2 INSTALLATION AND BASIC OPERATION 2-263.2.8 For Network Interface Cable Users (For Mac® OS X 10.1/10.2.1 or greater Users) (1) Switch off

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-1CHAPTER 3 THEORY OF OPERATION 1. ELECTRONICS 1.1 General Block Diagram Fig.

CHAPTER 3 THEORY OF OPERATION 3-21.2 Main PCB Block Diagram Fig. 3-2 shows the block diagram of the main PCB. Reset CircuitProgram + Font ROM1MB, 4M

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-31.3 Main PCB For the entire circuit diagram of the main PCB, see APPENDIX 4.1 to 4.6 ‘

TABLE OF CONTENTS iv 2.4.9 Rear cover sensor...

CHAPTER 3 THEORY OF OPERATION 3-41.3.3 IEEE1284 Stores the data received from the PC into DRAM as controlled by the DMA controller. It is applicable

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-51.3.5 Flash ROM A 16Mbit flash ROM (x 16bit) is fitted. Fig. 3-7 1.3.6 SDRAM Fig.

CHAPTER 3 THEORY OF OPERATION 3-61.3.7 Optional RAM A 32bit (100 pin) DIMM can be fitted as optional RAM. The main PCB has one slot and the capacity

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-71.3.8 EEPROM The EEPROM is BR24126 type of two-wire method with a 8192 x 8bit configur

CHAPTER 3 THEORY OF OPERATION 3-81.3.12 Video I/O The video signal output from the ASIC is reversed through a transistor and output after being corre

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-91.3.14 Power supply +5V is generated by the 3-pin regulator from astable 7V supplied f

CHAPTER 3 THEORY OF OPERATION 3-101.4 Engine PCB The gate array which transforms the serial signal from the main PCB into the parallel signal is moun

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-111.5 Power Supply 1.5.1 Low-voltage power supply The power supply uses a switching re

CHAPTER 3 THEORY OF OPERATION 3-121.5.2 High-voltage power supply The high-voltage power supply generates and outputs the voltages and currents for

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-132. MECHANICS 2.1 Overview of Printing Mechanism Fig. 3-19Paper CleanerPhotose

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL v3.28 Paper Feeder...

CHAPTER 3 THEORY OF OPERATION 3-142.2 Scanner Mechanism Fig. 3-20 This scanner mechanism supports a dual scanning system. (1) If you set documen

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-152.3 Paper Transfer 2.3.1 Paper supply The paper pick-up roller picks up one sheet of

CHAPTER 3 THEORY OF OPERATION 3-162.3.3 Paper eject After the printing image on the photosensitive drum is transferred onto the paper, the paper is f

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-172.4 Sensors 2.4.1 Cover sensors Detect opening and closing of the front cover. Fig.

CHAPTER 3 THEORY OF OPERATION 3-182.4.3 Cassette sensor / Paper empty sensor Detect if the paper tray is installed. They also detect if there is p

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-192.4.5 MP-PE sensor Detects if there is paper in the MP tray. Fig. 3-28 2.4.6 Docu

CHAPTER 3 THEORY OF OPERATION 3-202.4.7 Document front sensor /Document rear sensor Fig. 3-30 2.4.8 DX-sensor PCB ASSY Fig. 3-31 Document fr

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-212.4.9 Rear cover sensor Fig. 3-32 2.4.10 HP sensor Fig. 3-33 Rear cover sens

CHAPTER 3 THEORY OF OPERATION 3-222.5 Drum Unit 2.5.1 Photosensitive drum Generates the latent electrostatic image and develops the image on the drum

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-232.7.2 Exposure stage After the drum is positively charged, it is exposed to the light

TABLE OF CONTENTS vi 3.4 Paper Feeding Problems...6-18 4

CHAPTER 3 THEORY OF OPERATION 3-242.7.3 Developing Developing causes the toner to be attracted to the electrostatic image on the drum so as to transf

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 3-252.7.5 Fixing stage The image transferred to the paper by static electricity is fixed

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-1CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 1. SAFETY PRECAUTIONS To avoid creating

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-22. DISASSEMBLY FLOW AC CORD1DRUM UNIT2PAPER TRAY3DX FEED ASSY(MFC-8820D/8820DN, DCP-8025D/8025DN only)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-33. DISASSEMBLY PROCEDURE 3.1 AC Cord (1) Disconnect the AC cord from the machine.

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-43.3 Paper Tray (1) Close the front cover and pull out the paper tray. (2) Remove the paper from the paper

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-5NOTE: When replacing/re-assembling the pad holder ZL2 ASSY, remove the old grease and

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-6(5) Remove the two cup B M3x10 Taptite screws, and then remove the paper tray cover. Fig. 4-7 (6)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-7(7) Remove the pressure roller collar. (8) Remove the pressure roller shaft. Fig.

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-8(12) Remove the two cup M2.6x5 Taptite screws. (13) Release the lock lever, and then unhook the catches of t

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL vii3.11 Fine Adjustment of Scan Start/End Positions (Maintenance mode 54)...

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-9(15) Unhook the two catches (A) of the pressure plate while pulling the plastic frame

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-10NOTE: When re-assembling the pressure plate ASSY, ensure that the paper indicator arm is under the pressure

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-11(19) Remove the cup B M3x8 Taptite screw, and then remove the side guide gear and the

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-12NOTE: • When re-assembling the side guide racks, they should both be aligned so that the wide end of the r

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-13(24) Remove the paper rear guide. Fig. 4-20 Paper tray Paper rear guide 2 1 1

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-143.4 DX Feed ASSY (MFC-8820D/8820DN, DCP-8025D/8025DN only) (1) Remove the DX feed ASSY. Fig. 4-21 (2)

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-15NOTE: Set pressure roller, and assemble pressure roller spring after assembling DX ro

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-16(6) Remove the side regist guide. (7) Remove the left guide plate ASSY and DX paper switch pull arm. Fig

MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN SERVICE MANUAL 4-173.5 Access Cover / Battery (1) Remove the access cover. (2) Loosen the two access

CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY 4-183.6 Driver PCB Access Cover (1) Remove the bind B M4x12 Taptite screw, and then remove the driver PCB acc