Brother HL-1850 User manual

Brother Laser Printer
SERVICE MANUAL
MODEL: HL-185 /187 N
Read this manual thoroughly before maintenance work.
Keep this manual in a convenient place for quick and easy reference at all times.
January 2002
S -PRN031

© Copyright Brother Industries, Ltd. 2002
All rights reserved.
No part of this publication may be reproduced in any form or by any means without permission
in writing from the publisher.
Specifications are subject to change without notice.
Trademarks:
The brother logo is a registered trademark of Brother Industries, Ltd.
Apple, the Apple Logo, and acintosh are trademarks, registered in the United States and
other countries, and TrueType is a trademark of Apple computer, Inc.
Epson is a registered trademark and FX-80 and FX-850 are trademarks of Seiko Epson
Corporation.
Hewlett Packard is a registered trademark and HP LaserJet is a trademark of Hewlett Packard
Company.
IB , IB PC and Proprinter are registered trademarks of International Business achines
Corporation.
icrosoft and S-DOS are registered trademarks of icrosoft Corporation.
Windows is a registered trademark of icrosoft Corporation in the U.S. and other countries.

HL-1850/1870N SERVICE MANUAL
i
PREFACE
This service manual contains basic information required for after-sales service of the laser
printer (hereinafter referred to as "this machine" or "the printer"). This information is vital to the
service technician to maintain the high printing quality and performance of the printer.
This service manual covers the HL-185 /187 N printers.
This manual consists of the following chapters:
CHAPTER 1: GENERAL
Features, specifications, etc.
CHAPTER 2: INSTALLATION AND BASIC OPERATION
Installation conditions, Installation procedures, basic operation of the printer
etc.
CHAPTER 3: THEORY OF OPERATION
Basic operation of the mechanical system, the electrical system and the
electrical circuits and their timing information.
CHAPTER 4: DISASSEMBLY AND RE-ASSEMBLY
Procedures for disassembling and re-assembling the mechanical system.
CHAPTER 5: PERIODIC MAINTENANCE
Periodical replacements parts, consumable parts, etc.
CHAPTER 6: TROUBLESHOOTING
Reference values and adjustments, troubleshooting image defects,
troubleshooting malfunctions, etc.
CHAPTER 7: HIDDEN FUNCTIONS
Professional menu mode and Service menu mode, etc.
APPENDICES: Serial No. descriptions, Drum life & page counter, Diameter / circumference
of rollers, Connection diagrams, PCB circuit diagrams, etc.
Information in this manual is subject to change due to improvement or redesign of the product.
All relevant information in such cases will be supplied in service information bulletins
(Technical Information).
A thorough understanding of this printer, based on information in this service manual and
service information bulletins, is required for maintaining its print quality performance and for
improving the practical ability to find the cause of problems.

TABLE OF CONTENTS
ii
TABLE OF CONTENTS
REGULATION.............................................................................................viii
SAFETY INFORMATION...............................................................................x
CHAPTER 1 GENERAL .......................................................................... 1-1
1. FEATURES .............................................................................................................1-1
2. OVERVIEW .............................................................................................................1-3
3. SPECIFICATIONS...................................................................................................1-4
3.1 Printing ............................................................................................................................. 1-4
3.2 Functions.......................................................................................................................... 1-5
3.3 Electrical and echanical ................................................................................................ 1-6
3.4 Network ............................................................................................................................ 1-7
3.5 Paper................................................................................................................................ 1-8
3.5.1 Feedable paper................................................................................................................... 1-8
3.5.2 Paper cassette capacity....................................................................................................1-10
3.5.3 Print delivery ..................................................................................................................... 1-10
3.6 Printing Area................................................................................................................... 1-11
3.6.1 PCL5e/EPSON/IB emulation.......................................................................................... 1-11
3.6.2 PCL6/BR-Script3 emulation.............................................................................................. 1-14
CHAPTER 2 INSTALLATION AND BASIC OPERATION ...................... 2-1
1. CONDITIONS REQUIRED FOR INSTALLATION....................................................2-1
1.1 Power Supply ................................................................................................................... 2-1
1.2 Environment ..................................................................................................................... 2-1
1.3 System Requirements for Brother Printer Solution for Windows®.................................... 2-1
2. UNPACKING ...........................................................................................................2-2
3. INSTALL THE PRINTER .........................................................................................2-3
3.1 For All Users .................................................................................................................... 2-3
3.1.1 Install the drum unit assembly ............................................................................................ 2-4
3.1.2 Load paper into the paper cassette .................................................................................... 2-4
3.1.3 Print a test page.................................................................................................................. 2-5
3.2 For Windows® Users ........................................................................................................ 2-6
3.3 For acintosh Users ...................................................................................................... 2-10
4. PRINTING ETHODS...........................................................................................2-12
4.1 Printing from the Paper Cassette ................................................................................... 2-12
4.2 Printing from ulti-purpose Tray.................................................................................... 2-12
4.2.1 Printing on envelopes (Face up printing) .......................................................................... 2-14
4.2.2 Printing on label, transparency, etc. ................................................................................. 2-15
4.3 Printing to the Face up Output Tray (Face up Printing) ................................................. 2-17
4.4 Printing on Both Sides of the Paper (Duplex Printing) ................................................... 2-17
4.5 anual Feed ..................................................................................................................2-18

HL-1850/1870N SERVICE MANUAL
iii
5. CONTROL PANEL OPERATION...........................................................................2-19
5.1 Data LED Indications ..................................................................................................... 2-19
5.2 Panel Switches Functions .............................................................................................. 2-20
5.2.1 Go switch .......................................................................................................................... 2-20
5.2.2 Job Cancel switch............................................................................................................. 2-20
5.2.3 Reprint switch ................................................................................................................... 2-21
5.2.4 + & - switch ....................................................................................................................... 2-24
5.2.5 Set switch ......................................................................................................................... 2-24
5.2.6 Back switch....................................................................................................................... 2-24
5.3 LCD Display ................................................................................................................... 2-24
5.3.1 Backlights ......................................................................................................................... 2-25
5.3.2 Printer status messages ................................................................................................... 2-26
5.4 How to Use the Control Panel........................................................................................ 2-27
5.5 Control Panel Setting enu ........................................................................................... 2-28
5.5.1 Information........................................................................................................................ 2-29
5.5.2 Paper ................................................................................................................................ 2-29
5.5.3 Quality............................................................................................................................... 2-30
5.5.4 Setup ................................................................................................................................ 2-30
5.5.5 Print menu......................................................................................................................... 2-31
5.5.6 Network............................................................................................................................. 2-34
5.5.7 Interface............................................................................................................................ 2-34
5.5.8 Reset menu....................................................................................................................... 2-35
5.5.9 Set IP address .................................................................................................................. 2-35
5.5.10 About emulation modes .................................................................................................... 2-36
5.5.11 List of factory settings....................................................................................................... 2-36
5.6 Other Control Features .................................................................................................. 2-40
5.6.1 Sleep mode....................................................................................................................... 2-40
5.6.2 Inspection mode ............................................................................................................... 2-40
6. NETWORK BOARD OPERATION.........................................................................2-41
6.1 Installing the Network Board .......................................................................................... 2-41
6.2 Functions........................................................................................................................ 2-43
6.2.1 LED functions ................................................................................................................... 2-43
6.2.2 Factory default setting ...................................................................................................... 2-43
CHAPTER 3 THEORY OF OPERATION ................................................ 3-1
1. ELECTRONICS .......................................................................................................3-1
1.1 General Block Diagram .................................................................................................... 3-1
1.2 ain PCB Block Diagram................................................................................................. 3-2
1.3 ain PCB ......................................................................................................................... 3-3
1.3.1 ASIC.................................................................................................................................... 3-3
1.3.2 RO .................................................................................................................................... 3-5
1.3.3 Flash RO .......................................................................................................................... 3-6
1.3.4 SDRA ............................................................................................................................... 3-7
1.3.5 Optional RA ...................................................................................................................... 3-9
1.3.6 PCI bus ............................................................................................................................. 3-10
1.3.7 EEPRO .......................................................................................................................... 3-11
1.3.8 Reset circuit ...................................................................................................................... 3-11

TABLE OF CONTENTS
iv
1.3.9 Engine I/O......................................................................................................................... 3-12
1.3.10 Panel I/O........................................................................................................................... 3-12
1.4 Engine PCB.................................................................................................................... 3-13
1.5 BR-net PCB.................................................................................................................... 3-13
1.6 Power Supply .................................................................................................................3-14
1.6.1 Low-voltage Power Supply ............................................................................................... 3-14
1.6.2 High-voltage Power Supply............................................................................................... 3-15
2. ECHANICS .........................................................................................................3-16
2.1 Overview of Printing echanism.................................................................................... 3-16
2.2 Paper Transfer ...............................................................................................................3-18
2.2.1 Paper supply..................................................................................................................... 3-18
2.2.2 Paper registration ............................................................................................................. 3-18
2.2.3 Paper eject........................................................................................................................ 3-19
2.2.4 Duplex printing.................................................................................................................. 3-19
2.3 Sensors .......................................................................................................................... 3-20
2.3.1 Cover sensors................................................................................................................... 3-20
2.3.2 Toner sensors................................................................................................................... 3-20
2.3.3 DX tray sensor / DX paper size sensor............................................................................. 3-21
2.3.4 Rear cover sensor ............................................................................................................ 3-21
2.3.5 Cassette sensor / Paper empty sensor............................................................................. 3-22
2.3.6 Paper eject sensor............................................................................................................ 3-22
2.4 Drum Unit ....................................................................................................................... 3-23
2.4.1 Photosensitive drum ......................................................................................................... 3-23
2.4.2 Primary charger ................................................................................................................ 3-23
2.4.3 Transfer roller ................................................................................................................... 3-23
2.4.4 Cleaner ............................................................................................................................. 3-23
2.5 Toner Cartridge ..............................................................................................................3-23
2.6 Print Process.................................................................................................................. 3-23
2.6.1 Charging ........................................................................................................................... 3-23
2.6.2 Exposure stage................................................................................................................. 3-24
2.6.3 Developing........................................................................................................................ 3-25
2.6.4 Transfer ............................................................................................................................ 3-25
2.6.5 Fixing stage ...................................................................................................................... 3-26
CHAPTER 4 DISASSEMBLY AND RE-ASSEMBLY.............................. 4-1
1. SAFETY PRECAUTIONS ........................................................................................4-1
2. DISASSE BLY FLOW ............................................................................................4-2
3. DISASSE BLY PROCEDURE................................................................................4-3
3.1 AC Cord ........................................................................................................................... 4-3
3.2 Drum Unit ......................................................................................................................... 4-3
3.3 Paper Cassette ................................................................................................................ 4-4
3.4 Network Board (For HL-1870N only).............................................................................. 4-11
3.5 Top Cover ...................................................................................................................... 4-12
3.6 DX Feed ASSY............................................................................................................... 4-16
3.7 Rear Cover..................................................................................................................... 4-20
3.8 Rear Cover R & L / Side Cover R & L ............................................................................ 4-22
3.9 P Cover ASSY............................................................................................................. 4-23

HL-1850/1870N SERVICE MANUAL
v
3.10 Process Unit Cover ASSY.............................................................................................. 4-25
3.11 Laser Unit....................................................................................................................... 4-26
3.12 Fixing Unit ...................................................................................................................... 4-27
3.13 Paper Pick-up Roller ASSY............................................................................................ 4-39
3.14 Feed P Unit ................................................................................................................. 4-40
3.15 Drive Unit ....................................................................................................................... 4-42
3.16 Low-voltage Power Supply PCB ASSY.......................................................................... 4-47
3.17 ain PCB ASSY............................................................................................................. 4-48
3.18 Fan otor / Fan otor 60 .............................................................................................. 4-48
3.19 Base Plate...................................................................................................................... 4-49
3.20 Engine PCB ASSY / High-voltage Power Supply PCB ASSY........................................ 4-49
3.21 DX Sensor PCB ASSY................................................................................................... 4-51
3.22 Toner Sensor PCB Unit (Light Reception) ..................................................................... 4-52
3.23 Toner LED PCB Unit (Light Emission) ........................................................................... 4-52
3.24 Paper Feed Roller ASSY................................................................................................ 4-53
3.25 First Feed Roller ASSY .................................................................................................. 4-53
3.26 Exit Roller Unit................................................................................................................ 4-55
3.27 Harness Winding Form .................................................................................................. 4-57
4. PACKING ..............................................................................................................4-58
CHAPTER 5 PERIODIC MAINTENANCE............................................... 5-1
1. CONSU ABLE PARTS...........................................................................................5-1
1.1 Drum Unit ......................................................................................................................... 5-1
1.2 Toner Cartridge ................................................................................................................ 5-2
2. PERIODICAL REPLACE ENT PARTS...................................................................5-5
3. PERIODICAL CLEANING........................................................................................5-6
3.1 Cleaning the Printer Exterior ............................................................................................ 5-6
3.2 Cleaning the Drum Unit .................................................................................................... 5-6
3.3 Cleaning the Scanner Window......................................................................................... 5-7
3.4 Cleaning the Electrical Terminals..................................................................................... 5-8
4. TBF / TTR..........................................................................................................5-9
CHAPTER 6 TROUBLESHOOTING ....................................................... 6-1
1. INTRODUCTION .....................................................................................................6-1
1.1 Initial Check...................................................................................................................... 6-1
1.2 Warnings for aintenance Work...................................................................................... 6-2
1.3 Identify the Problem .........................................................................................................6-3
2. OPERATOR CALLS & SERVICE CALLS ................................................................6-4
2.1 Operator Calls .................................................................................................................. 6-4
2.2 Service Calls .................................................................................................................... 6-6
3. PAPER PROBLE S................................................................................................6-9
3.1 Paper Loading Problems.................................................................................................. 6-9
3.2 Paper Jams .................................................................................................................... 6-10
3.2.1 Clearing jammed paper..................................................................................................... 6-11

TABLE OF CONTENTS
vi
3.2.2 Causes & countermeasures.............................................................................................. 6-19
3.3 Paper Feeding Problems ............................................................................................... 6-20
4. SOFTWARE SETTING PROBLE S .....................................................................6-22
5. ALFUNCTIONS ..................................................................................................6-25
6. I AGE DEFECTS .................................................................................................6-31
6.1 Image Defect Examples ................................................................................................. 6-31
6.2 Troubleshooting Image Defect ....................................................................................... 6-32
6.3 Location of Grounding Contacts..................................................................................... 6-50
6.3.1 Drum unit .......................................................................................................................... 6-50
6.3.2 Printer body & Paper cassette .......................................................................................... 6-50
7. INCORRECT PRINTOUT ......................................................................................6-51
8. NETWORK PROBLE ..........................................................................................6-54
8.1 Installation Problem........................................................................................................ 6-54
8.2 Intermittent Problem ....................................................................................................... 6-55
8.3 TCP/IP Troubleshooting................................................................................................. 6-56
8.4 UNIX Troubleshooting.................................................................................................... 6-56
8.5 Windows NT/LAN Server (TCP/IP) Troubleshooting ..................................................... 6-57
8.6 Windows 95/98/ e (or later) Peer to Peer Print (LPR) Troubleshooting ....................... 6-57
8.7 Windows 95/98/ e (or later) Peer to Peer (HP JetAdmin Compatible ethod) Troubleshooting.....
....................................................................................................................................... 6-58
8.8 Windows 95/98/ e/NT 4.0/2000 (or later) Peer to Peer Print (NetBIOS) Troubleshooting ...
....................................................................................................................................... 6-58
8.9 Internet Print (TCP/IP) Troubleshooting......................................................................... 6-58
8.10 Novell Netware Troubleshooting .................................................................................... 6-59
8.11 AppleTalk Troubleshooting ............................................................................................ 6-59
8.12 Apple TCP/IP Printing (System 8.6 or later)................................................................... 6-60
8.13 Web Browser Troubleshooting (TCP/IP)........................................................................ 6-60
9. INSPECTION ODE .............................................................................................6-61
9.1 Entering Inspection ode .............................................................................................. 6-61
9.2 Sensor Check ode....................................................................................................... 6-62
CHAPTER 7 HIDDEN FUNCTIONS ........................................................ 7-1
1. ENTERING HIDDEN FUNCTION ENU ODES...................................................7-1
2. PROFESSIONAL ENU ODE..............................................................................7-2
2.1 Enabling and Disabling Professional enu ode............................................................ 7-2
2.2 Function Table ................................................................................................................. 7-3
3. SERVICE ENU ODE..........................................................................................7-7
3.1 Entering the Service enu ode..................................................................................... 7-7
3.2 Function Table ................................................................................................................. 7-7
4. OTHER HIDDEN FUNCTION ENUS ....................................................................7-9
4.1 Hidden Function enus Enabled by Pressing Switch(es) When Turning the achine on ....
......................................................................................................................................... 7-9
4.2 Drum Life Reset Function ................................................................................................ 7-9
4.3 Parts life Reset Function .................................................................................................. 7-9

HL-1850/1870N SERVICE MANUAL
vii
APPENDICES
1. CONNECTION DIAGRA , HL-1850/1870N........................................................... A-1
2. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (1/6) .......................................... A-2
3. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (2/6) .......................................... A-3
4. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (3/6) .......................................... A-4
5. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (4/6) .......................................... A-5
6. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (5/6) .......................................... A-6
7. AIN PCB CIRCUIT DIAGRA , HL-1850/1870N (6/6) .......................................... A-7
8. ENGINE PCB CIRCUIT DIAGRA , HL-1850/1870N (1/2) ..................................... A-8
9. ENGINE PCB CIRCUIT DIAGRA , HL-1850/1870N (2/2) ..................................... A-9
10. NETWORK BOARD PCB CIRCUIT DIAGRA , HL-1850/1870N.......................... A-10
11. LOW-VOLTAGE POWER SUPPLY PCB CIRCUIT DIAGRA (100V) ................. A-11
12. LOW-VOLTAGE POWER SUPPLY PCB CIRCUIT DIAGRA (200V) ................. A-12
13. HIGH-VOLTAGE POWER SUPPLY PCB CIRCUIT DIAGRA ............................ A-13
14. SERIAL NO. DESCRIPTIONS.............................................................................. A-14
15. DIA ETER / CIRCU FERENCE OF ROLLERS.................................................. A-16
16. PRINT SPEEDS WITH VARIOUS SETTINGS...................................................... A-17
17. HOW TO KNOW DRU UNIT LIFE & PAGE COUNTER .................................... A-18
18. HOW TO USE THE SELF-DIAGNOSTICS TOOLS ............................................. A-23
19. NVRA DEFAULT VALUE................................................................................... A-27
20. PAPER CASSETTE INFOR ATION (FOR EUROPE ONLY)............................... A-28
21. GUIDELINES FOR LEAD FREE SOLDER ( AIN PCB ASSY) .......................... A-29
22. HOW TO REWRITE HL-1850/1870N FLASH RO ............................................. A-30
INDEX

REGULATION
viii
REGULATION
LASER SAFETY (11 - 12 V MODEL ONLY)
This printer is certified as a Class 1 laser product under the US Department of Health and
Human Services (DHHS) Radiation Performance Standard according to the Radiation
Control for Health and Safety Act of 1968. This means that the printer does not produce
hazardous laser radiation.
Since radiation emitted inside the printer is completely confined within the protective
housing and external covers. the laser beam cannot escape form the machine during any
phase of user operation.
FDA REGULATIONS (11 - 12 V MODEL ONLY)
The US Food and Drug Administration (FDA) has implemented regulations for laser
products manufactured on and after August 2, 1976. Compliance is mandatory for
products marketed in the United States. One of the following labels on the back of the
printer indicates compliance with the FDA regulations and must be attached to laser
products marketed in the United States.
The label for Japanese manufactured products
ANUFACTURED: K
BROTHER INDUSTRIES, LTD.
15-1, Naeshiro-cho, izuho-ku, Nagoya 467-8561,
Japan.
This product complies with FDA radiation performance
standards, 21 CFR Subchapter J.
The label for Chinese manufactured products
ANUFACTURED: C
BROTHER Corporation (Asia) Ltd.
Shenzen Buji Nan Ling Factory
Gold Garden Ind., Nan Ling Village, Buji, Rong Gang,
Shenzen, CHINA
This product complies with FDA radiation performance
standards, 21 CFR Subchapter J.
Caution
Use of controls, adjustments or performance of procedures other than those specified in
this manual may result in hazardous radiation exposure.

HL-1850/1870N SERVICE MANUAL
ix
IEC 825 (22 -24 V MODEL ONLY)
This printer is a Class 1 laser product as defined in IEC 825 specifications. The label
shown below is attached in countries where required.
This printer has a laser diode which emits invisible laser radiation in the Laser Unit. The
Laser Unit should not be opened without disconnecting the two connectors connected with
the AC power supply and laser unit. Since the variable resistor in the laser unit is adjusted
in accordance with the standards, never touch it.
Caution
Use of controls, adjustments or performance of procedures other than those specified in
this manual may result in hazardous radiation exposure.
For Finland and Sweden
LUOKAN 1 LASERLAITE
KLASS 1 LASER APPARAT
Varoitus! Laitteen käyttäminen muulla kuin tässä käyttöohjeessa mainitulla tavalla saattaa
altistaa käyttäjän turvallisuusluokan 1 ylittävälle näkymättömälle lasersäteilylle.
Varning  Om apparaten används på annat sätt än i denna Bruksanvisning specificerats,
kan användaren utsättas för osynlig laserstrålning, som överskrider gränsen för laserklass
1.

SAFETY INFORMATION
x
SAFETY INFORMATION
CAUTION FOR LASER PRODUCT (WARNHINWEIS FUR LASER DRUCKER)
CAUTION: When the machine during servicing is operated with the cover open, the
regulations of VBG 93 and the performance instructions for VBG 93 are
valid.
CAUTION: In case of any trouble with the laser unit, replace the laser unit itself. To
prevent direct exposure to the laser beam, do not try to open the enclosure
of the laser unit.
ACHTUNG: Im Falle von Störungen der Lasereinheit muß diese ersetzt werden. Das
Gehäuse der Lasereinheit darf nicht geöffnet werden, da sonst
Laserstrahlen austreten können.
<Location of the laser beam window>
ADDITIONAL INFORMATION
When servicing the optical system of the printer, be careful not to place a screwdriver or
other reflective object in the path of the laser beam. Be sure to take off any personal
accessories such as watches and rings before working on the printer. A reflected beam,
though invisible, can permanently damage the eyes.
Since the beam is invisible, the following caution label is attached on the laser unit.

HL-1850/1870N SERVICE MANUAL
xi
CAUTION
INVISIBLE LASER RADIATION WHEN OPEN AND INTERLOCK DEFEATED.
AVOID DIRECT EXPOSURE TO BEAM. CLASS 3B LASER PRODUCT.
ADVARSEL
USYNLIG LASER STRÅLING NÅR KABINETLÅGET STÅR ÅBENT.
UNGDÅ DIREKTE UDSÆTTELSE FOR STRÅLING. KLASSE 3B LASER.
VARNING
OSYNLIG LASERSTRÅLNING NÄR DENNA DEL ÄR ÖPPNAD OCH SPÄRRAR
ÄR URKOPPLADE. STRÅLEN ÄR FARLIG. KLASS 3B LASER APPARAT.
VARO!
AVATTAESSA JA SUOJALUKITUS OHITETTAESSA OLET ALTTIINA
NÄKYMÄTTÖMÄLLE LASERSÄTEILYLLE. ÄLÄ KATSO SÄTEESEEN. LUOKAN
3B LASERLAITE.
ADVARSEL
USYNLIG LASERSTRÅLING.UNNGÅ DIREKTE KONTAKT MED LASERENHETEN
NÅR TOPPDEKSELET ER ÅPENT. KLASSE 3B LASERPRODUKT.
ATTENTION
RADIATIONS LASER INVISIBLES QUANDOUVERT ET VERROUILLAGE ENLEVE.
EVITER EXPOSITIONS DIRECTES AU FAISCEAU. PRODUIT LASER CLASSE 3B.
VORSICHT
UNSICHTBARE LASERSTRAHLUNG WENN ABDECKUNG
GEÖFFENT UND SICHERHEITSVERRIEGELUNG
ÜBERBRÜCKT. NICHT DEM STRAHL AUSSETZEN.
SICHERHEITSKLASSE 3B.
ATENCIÓN
RADIACIÓN LASER INVISIBLE CUANDO SE ABRE
LA TAPA Y EL INTERRUPTOR INTERNO ESTÁ
ATASCADO. EVITE LA EXPOSICIÓN DIRECTA
DE LOS OJOS. PRODUCTO LASER CLASE 3B.

SAFETY INFORMATION
xii
DEFINITIONS OF WARNINGS, CAUTIONS AND NOTES
The following conventions are used in this service manual:
WARNING
Indicates warnings that must be observed to prevent possible personal injury.
!
CAU ION:
Indicates cautions that must be observed to service the printer properly or prevent damage
to the printer
NOTE:
Indicates notes and useful tips to remember when servicing the printer
**Listed below are the various kinds of WARN NG messages included in this manual.
WARNING
Always turn off the power switch and unplug the power cord from the power outlet
before accessing any parts inside the printer.
WARNING
Some parts inside the printer are extremely hot immediately after the printer is used.
When opening the front cover or rear cover to access any parts inside the printer,
never touch the red colored parts shown in the following figures.
WARNING
If you analyze malfunctions with the power plug inserted into the power outlet,
special caution should be exercised even if the power switch is OFF because it is a
single pole switch.

HL-1850/1870N SERVICE MANUAL
xiii

HL-1850/1870N SERVICE MANUAL
1-1
CHAPTER 1 GENERAL
1. FEATURES
This printer has the following features;
High Resolution and Fast Print Speed
True 600 x 600 dots / true 300 x 300 dots per inch (dpi) and 2400 x 600 dots per inch (dpi) for
graphics with icrofine toner and up to 18 pages per inutes (pp ) print speed for A4 and 19
pages per inutes (pp ) print speed for Letter paper.
Versatile Paper Handling
The printer loads paper auto atically fro the paper cassette. The paper cassette can hold
A4, letter, B5 (ISO), B5 (JIS), A5, B6 (ISO), A6, Executive and Legal sizes of paper. The
anual feed slot allows anual paper loading sheet by sheet so you can use a variety of types
and sizes of paper.
Front peration
Basic operation of the printer can be controlled fro the control panel.
Enhanced Printing Performance and User-Friendly peration for Windows


The dedicated printer driver for Microsoft Windows 95/98/Me, Windows NT 4.0 and
Windows 2000/XP are available on the CD-ROM supplied with your printer. You can easily
install the into your Windows syste using our installer progra . The driver supports our
unique co pression ode to enhance printing speed in Windows applications and allows you
to choose various printer settings including toner save ode, custo paper size, sleep ode,
gray scale adjust ent, resolution, water ark and any layout functions. You can easily
setup these print options through the Printer Setup Menu.
Printer Status Monitor with Bi-directional Parallel Interface
The printer driver can onitor the status of your printer using bi-directional parallel
co unications. IEEE-1284 bi-directional parallel printer cable is reco ended.
The printer status onitor progra can show the current status of your printer. When printing,
the ani ated dialog box appears on your co puter screen to show the current printing
process. If an error occurs, a dialog box will appear to let you know what to correct. If you
have turned on the interactive Help (Windows 95/98 only) you can get visual guidance on
your PC screen on the actions in the event of certain printer errors.
Quick Print Setup
The Quick Print Setup is a convenient utility to allow you to ake changes to frequently used
driver settings easily without having to open the printer properties selection box every ti e. It
is launched auto atically when this printer driver is selected. You can change the settings by
clicking on the icon with the right ouse button.
Enhanced Memory Management
The printer provides its own data co pression technology in its printer hardware and the
supplied printer driver software, which can auto atically co press graphic data and font data
efficiently into the printers e ory. You can avoid e ory errors and print ost full page 600
dpi graphic and text data, including large fonts, with the standard printer e ory.

CHAPTER 1 GENERAL
1-2
USB Interface (for Windows

 98 / 2000/XP, iMac and Power Macintosh)
The printer can be connected using the Universal Serial Bus (USB) interface to a PC or Mac
which has a USB interface. Drivers that allow you to use the USB port are provided on the
CD-ROM supplied with the printer.
Popular Printer Emulation Support
These printers support the following printer e ulation odes;
HP LaserJet (PCL6), PostScript Level 3 language e ulation (Brother BR-Script Level 3),
Epson FX-850 and IBM Proprinter XL.
When you use DOS application software or Windows version 3.0 or earlier, you can use any
of these e ulations to operate the HL-1850/1870N printers. The printers also support auto-
e ulation switching between HP, Brother BR-Script 3 and Epson or HP, BR-Script 3 and IBM.
If you want to set the printer e ulation, you can do it using the Re ote Printer Console
Progra .
High Resolution Control & Advanced Photoscale Technology
High Resolution Control (HRC) technology provides clear and crisp printouts. Use this function
to get s ooth text print quality.
Advanced Photoscale Technology (APT) enables the printer to print graphics in 256
grayscales, producing nearly photographic quality. Use this function when you want to print
photographic i ages.
Environment-Friendly
<Econo y Printing Mode>
This feature will cut your printing cost by saving toner. It is useful for obtaining draft copies for
proof-reading. You can select the 50% toner saving econo y ode through the Windows
printer driver supplied with your printer.
<Sleep Mode (Power Save Mode)>
Sleep ode auto atically reduces power consu ption when the printer is not in use for a
certain period of ti e. The printer consu es less than 12W when in sleep ode.
<Low Running Cost>
Since the toner cartridge is separate fro the dru unit, you need to replace only the toner
cartridge after printing around 6,500 pages at 5% coverage for A4 paper for the standard
cartridge, which is both cost effective and ecologically friendly.
Bar Code Print
The printer can print the following 11 types of bar codes;
• Code 39 • US-PostNet • EAN-8
• Code 128 • ISBN • EAN-13
• Interleaved 2 of 5 • UPC-A • EAN-128
• Codabar • UPC-E
Network Feature (for HL-1870N only)
The Brother printer has built in ulti protocol network capability as standard. This allows
ultiple host co puters to share the printer on a 10/100Mbit Ethernet network. Any users can
print their jobs as if the printer was directly connected to their co puter. Users on Windows®
95/98/Me, Windows® NT, Windows® 2000/XP, UNIX, Novell, Apple Macintosh, LAN server and
OS/2 Warp server co puter si ultaneously can access this printer. For further infor ation,
see the Network Users Guide supplied with the printer.

HL-1850/1870N SERVICE MANUAL
1-3
2. VERVIEW
<Front View>
Fig. 1-1
<Rear View>
Fig. 1-2
Multi-purpose tray extension
Paper cassette
Control panel
Extension flap
Front cover
Multi-purpose tray
Cover release button
Power switch
Parallel interface connector
Face up output tray
Face up tray extension
(Rear cover)
USB connectorPCB access plate
Face down output tray
Interface cover
AC power inlet
Duplex tray
Paper adjust ent lever
for duplex printing

CHAPTER 1 GENERAL
1-4
3. SPECIFICATI NS
3.1 Printing
Print ethod Electrophotography by se iconductor laser bea scanning
Laser Wavelength: 780 n
Output: 5 W ax
Resolution HQ1200 (for Windows® 95/98/Me, WindowsNT® 4.0, Windows®
2000/XP, and Mac OS)
600 dpi (for Windows® 95/98/Me, WindowsNT® 4.0, Windows®
2000/XP, DOS and Mac OS)
300 dpi (for Windows® 95/98/Me, WindowsNT® 4.0, Windows®
2000/XP, and Mac OS)
Print quality Nor al printing ode
Econo y printing ode (up to 25% and 50% toner saving)
Print speed Nor al: Up to 18 pages/ inute (A4)
UP to 19 pages/ inute (Letter-size paper)
Duplex printing: Up to 8.5 pages/ inute*
(when loading A4 or Letter-size paper fro the standard paper
cassette.)
War -up Max. 20 seconds at 23°C (73.4°F)
First print Max. 12 seconds
(when loading A4 or Letter-size paper fro the standard paper
cassette.)
Print edia Toner cartridge
Life expectancy: 6,500 pages/cartridge
(when printing A4 or Letter-size paper at 5% print coverage)
Developer Dru unit
Life expectancy: 20,000 pages/dru unit
*NOTE:
Print s eed varies de ending on the a er size or media ty e. For details, refer to APPENDIX
16 PRINT SPEEDS WITH VARIOUS SETTINGS.

HL-1850/1870N SERVICE MANUAL
1-5
3.2 Functions
CPU Fujitsu MB86834 100MHz
E ulation Brother Printing Solution for Windows
Auto atic e ulation selection a ong HP LaserJet (PCL level 6),
Brother BR-Script Level 3, EPSON FX-850 or IBM Proprinter XL
Printer driver <PCL Driver>
Windows 95/98/Me, Windows NT 4.0, Windows® 2000/XP driver,
supporting Brother Native Co pression ode
<PS Driver>
PPD file driver for Windows 95/98/Me, Windows NT 4.0, Windows®
2000/XP driver and Macintosh driver
<Others>
• iMac, Power Macintosh with USB printer driver
• Optional Macintosh driver available for Syste 6.0.7 or higher
Interface •Bi-directional parallel
•Universal Serial Bus (USB)
•10/100 BaseTX Ethernet network interface (optional for HL-1850)
•Optional IrDA
Me ory HL1850: 16 Mbytes
HL1870N: 32 Mbytes
Expandable up to 136 Mbytes for HL1850 and 144 Mbytes for
HL1870N by installing an industry standard DIMM*
Control Panel •Display LCD: 1 line, 16 digit, 3 color
LED: 1 LED
•Buttons 7 keys
Diagnostics Self-diagnostic progra
*NOTE:
The DIMM must have the following s ecifications;
Ty e: 100 in
Access time: 60 nsec - 80 nsec
Ca acity: 16, 32, 64, 128 Mbyte
Height: 35.0 mm (1.38 inches) or less
Out ut: 32 bit or 36 bit (inde endent of arity)