Brother HL-4040CN User manual

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Brother Color Laser Printer
SERVICE MANUAL
MODEL:
HL-4040CN/4050CDN/4070CDW
Read this manual thoroughly before maintenance work.
Keep this manual in a convenient place for quick and easy reference at all times.
February 2007
SM-PRN061
(2)

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PREFACE
This service manual contains basic information required for after-sales service of the laser
printer (hereinafter referred to as "the machine"). This information is vital to the service
personnel to maintain the high printing quality and performance of the machine.
This service manual covers the HL-4040CN/4040CDN/4050CDN/4070CDW machines.
This manual consists of the following chapters:
CHAPTER 1: TROUBLESHOOTING
Details of error messages and codes that the incorporated self-diagnostic function of the
machine will display if any error or malfunction occurs. If any error message appears, refer
to this chapter to find which parts should be checked or replaced.
The latter half of this chapter provides sample problems that could occur in the main
sections of the machine and related troubleshooting procedures.
CHAPTER 2: PERIODICAL MAINTENANCE
Details of consumable parts and periodical maintenance parts. This chapter also covers
procedures for disassembling and assembling periodical maintenance parts.
CHAPTER 3: DISASSEMBLY AND ASSEMBLY
Details of procedures for disassembling and assembling of the machine together with
related notes. The disassembly order flow provided enables you to see at a glance the
quickest way to get to parts involved.
At the start of a disassembly job, you can check the disassembly order flow that guides you
through a shortcut to get to the object parts.
This chapter also covers screw tightening torques and lubrication points to which the
specified lubrications should be applied during assembly jobs.
CHAPTER 4: ADJUSTMENTS AND UPDATING OF SETTINGS,
REQUIRED AFTER PARTS REPLACEMENT
Details of adjustments and updating of settings, which are required if the main PCB and
some other parts have been replaced. This chapter also covers how to update the
firmware.
CHAPTER 5: SERVICE FUNCTIONS
Describes the maintenance mode which is exclusively designed for the purpose of
checking the settings and adjustments using the keys on the panel.
This chapter also covers hidden function menus, which activate settings and functions or
reset the parts life.
CHAPTER 6: CIRCUIT DIAGRAMS, WIRING DIAGRAM
Provides the Circuit Diagrams and Wiring Diagram for the connections of the PCBs.

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APPENDIX 1: WORKER SWITCH (WSW)
Describes the functions of the worker switches, which can be divided into two groups: one
is for customizing preferences designed for the destination and the other is for modifying
preferences that match the machine to the environmental conditions. Use the latter group if
the machine malfunctions due to mismatching.
APPENDIX 2: DELETION OF PERSONAL INFORMATION
Provides instructions on how to delete personal information recorded in the machine.
APPENDIX 3: SERIAL NUMBERING SYSTEM
APPENDIX 4: SCREW CATALOGUE
APPENDIX 5: HOW TO MAKE THE DRUM UNIT REMOVE SHEET
APPENDIX 6: REFERENCES
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 machine, 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.
There is the service reference manual as well. This service reference manual contains
“SPECIFICATIONS”, “THEORY OF OPERATION”, “TONER CARTRIDGE WEIGHT
INFORMATION”, “REFERENCES”, and “GLOSSARY”.

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TABLE OF CONTENTS
REGULATION............................................................................................ VIII
SAFETY INFORMATION............................................................................ XII
CHAPTER 1 TROUBLESHOOTING ........................................................ 1-1
1. INTRODUCTION .........................................................................................................1-1
1.1 Precautions ........................................................................................................................ 1-1
1.2 Initial Check........................................................................................................................ 1-1
2. ERROR CODES..........................................................................................................1-3
2.1 Error Indication ................................................................................................................... 1-3
2.2 Error Cause and Remedy .................................................................................................. 1-5
2.2.1 Recoverable Error by User Check ........................................................................... 1-5
2.2.2 Service Call Error................................................................................................... 1-10
3. PAPER FEEDING PROBLEMS.................................................................................1-38
3.1 No Feeding....................................................................................................................... 1-38
3.2 Double Feeding................................................................................................................ 1-38
3.3 Paper Jam ........................................................................................................................ 1-39
3.4 Dirt on Paper .................................................................................................................... 1-40
3.5 Wrinkles............................................................................................................................ 1-40
4. IMAGE DEFECT TROUBLESHOOTING...................................................................1-41
4.1 Image Defect Examples ................................................................................................... 1-41
4.2 Diameter of Rollers .......................................................................................................... 1-42
4.3 Troubleshooting Image Defect......................................................................................... 1-42
5. SOFTWARE SETTING PROBLEMS.........................................................................1-59
6. NETWORK PROBLEMS ...........................................................................................1-60
7. OTHERS PROBLEMS...............................................................................................1-61
CHAPTER 2 PERIODICAL MAINTENANCE........................................... 2-1
1. CONSUMABLE PARTS...............................................................................................2-1
2. PERIODICAL REPLACEMENT PARTS ......................................................................2-2
2.1 Periodical Replacement Parts............................................................................................ 2-2
2.2 Procedures to Replace Periodical Replacement Parts...................................................... 2-3
2.2.1 Fuser Unit & Fuser Filter Frame ASSY.................................................................... 2-3
2.2.2 Laser Unit................................................................................................................. 2-7
2.2.3 Paper Feeding Kit (PF Kit1, PF Kit2) ..................................................................... 2-22
2.2.4 MP Paper Feeding Kit............................................................................................ 2-27
2.3 Parts Life Reset Function................................................................................................. 2-32

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CHAPTER 3 DISASSEMBLY AND ASSEMBLY..................................... 3-1
1. SAFETY PRECAUTIONS............................................................................................3-1
2. PACKING ....................................................................................................................3-2
3. SCREW TORQUE LIST ..............................................................................................3-3
4. LUBRICATION ............................................................................................................3-6
5. OVERVIEW OF GEARS............................................................................................3-12
6. HARNESS ROUTING................................................................................................3-17
7. DISASSEMBLY FLOW..............................................................................................3-24
8. DISASSEMBLY PROCEDURE .................................................................................3-25
8.1 AC Cord............................................................................................................................3-25
8.2 Toner Cartridge................................................................................................................3-25
8.3 Drum Unit.........................................................................................................................3-28
8.4 Belt Unit............................................................................................................................3-30
8.5 Waste Toner Box..............................................................................................................3-30
8.6 Paper Tray........................................................................................................................3-31
8.7 DX Feed ASSY (HL-4040CDN/ 4050CDN/ 4070CDW only)...........................................3-33
8.8 MP Cover ASSY/ MP Paper Guide ASSY .......................................................................3-34
8.9 MP Lift Arm 2/ MP Roller Holder ASSY ...........................................................................3-37
8.10 Fuser Unit/ Toner Filter Frame ASSY............................................................................3-40
8.11 Back Cover Upper..........................................................................................................3-42
8.12 Paper Eject ASSY DX/SX..............................................................................................3-43
8.13 Back Cover ASSY..........................................................................................................3-45
8.14 Paper Guide DX/ HV TR Top Cover ..............................................................................3-46
8.15 Transfer HVPS PCB Unit...............................................................................................3-47
8.16 Registration-mark Sensor PCB ASSY 1, 2/ Density Sensor/ Registration Relay PCB
ASSY/ Transfer HVPS PCB ASSY................................................................................3-48
8.17 Side Cover L ASSY........................................................................................................3-54
8.18 Side Plate LB..................................................................................................................3-55
8.19 Drum Unit Fan (OPC).....................................................................................................3-56
8.20 Side Cover R ASSY ....................................................................................................... 3-57
8.21 Roller Holder ASSY........................................................................................................3-58
8.22 Paper Feed Frame Unit/ T1 PE/Edge Sensor PCB ASSY ............................................3-59
8.23 Belt Cleaner Release Sensor PCB ASSY......................................................................3-67
8.24 THM/HUM Sensor Holder ASSY ...................................................................................3-68
8.25 Release Rack.................................................................................................................3-70
8.26 Front Door Unit ASSY....................................................................................................3-71
8.27 Harness Cover MP.........................................................................................................3-74

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8.28 Front Door Sub...............................................................................................................3-75
8.29 EL Electrode Spring L/R.................................................................................................3-76
8.30 Hook Cover/ Front Cover Release Button/ Button Spring/ Front Door Main.................3-77
8.31 Hook Shaft/ Hook/ Hook Spring.....................................................................................3-79
8.32 Engine PCB ASSY.........................................................................................................3-80
8.33 Main PCB ASSY/ Ground Plate/ Ground Spring Plate .................................................. 3-81
8.34 Waste Toner Near/Full Sensor ASSY............................................................................3-83
8.35 Top Cover ASSY............................................................................................................3-85
8.36 Top Cover Panel ASSY..................................................................................................3-86
8.37 LCD Panel PCB ASSY...................................................................................................3-87
8.38 Rubber Key Printed ASSY.............................................................................................3-88
8.39 Key Cap Up, Down, L, R................................................................................................3-88
8.40 USB Host Relay PCB ASSY..........................................................................................3-89
8.41 LCD Panel ASSY/ LCD Stopper ....................................................................................3-90
8.42 Paper Chute...................................................................................................................3-91
8.43 Top Cover R...................................................................................................................3-93
8.44 Top Cover L ASSY.........................................................................................................3-93
8.45 Wireless LAN PCB ASSY (HL-4070CDW only).............................................................3-94
8.46 Laser Unit/ Hook Slope..................................................................................................3-96
8.47 Develop Drive Motor ASSY............................................................................................3-98
8.48 Drum Drive ASSY/ Drum Phase Sensor PCB ASSY 1, 2............................................3-103
8.49 Drive Frame Unit ASSY ...............................................................................................3-107
8.50 Paper Feed/Belt Cleaner Motor ASSY.........................................................................3-108
8.51 Develop Release Sensor PCB ASSY..........................................................................3-109
8.52 Develop Press Drive L ASSY.......................................................................................3-109
8.53 Front Cover Interlock Switch ASSY .............................................................................3-112
8.54 Toner Sensor PCB ASSY K, Y, M, C (TE/NEW) .........................................................3-113
8.55 New Toner Actuator/ New Toner Actuator Spring .......................................................3-117
8.56 Side Plate R ASSY.......................................................................................................3-118
8.57 Drum Lock Lever L.......................................................................................................3-119
8.58 Drum Lock Lever R......................................................................................................3-120
8.59 Charge HVPS PCB ASSY............................................................................................3-121
8.60 Toner LED PCB ASSY.................................................................................................3-123
8.61 Fuser Unit Fan (FU).....................................................................................................3-124
8.62 LVPS Fan (PS).............................................................................................................3-125
8.63 Air Intake Fan (AIR) .....................................................................................................3-126
8.64 PS PCB Unit.................................................................................................................3-127
8.65 Belt Unit Drive Motor ASSY .........................................................................................3-131

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9. DISASSEMBLY PROCEDURE (LT-100CL) (HL-4050CDN/ 4070CDW ONLY)......3-134
9.1 LT Paper Tray ................................................................................................................3-134
9.2 LT Cover Rear................................................................................................................3-138
9.3 LT Cover Left..................................................................................................................3-139
9.4 LT Cover Right...............................................................................................................3-140
9.5 LT Relay PCB ASSY......................................................................................................3-141
9.6 LT Solenoid ASSY..........................................................................................................3-142
9.7 Collar 6...........................................................................................................................3-143
9.8 Cassette Switch ASSY...................................................................................................3-143
9.9 LT Paper Feed Frame Unit ............................................................................................3-145
CHAPTER 4 ADJUSTMENTS AND UPDATING OF SETTING,
REQUIRED AFTER PARTS REPLACEMENT ................... 4-1
1. IF YOU REPLACE THE MAIN PCB ............................................................................4-1
2. IF YOU REPLACE THE ENGINE PCB......................................................................4-12
3. IF YOU REPLACE THE TRANSFER HVPS PCB UNIT OR REGISTRATION-
MARK SENSOR PCB ASSY 1, 2..............................................................................4-15
4. IF YOU REPLACE THE LASER UNIT.......................................................................4-16
CHAPTER 5 SERVICE FUNCTIONS....................................................... 5-1
1. MAINTENANCE MODE...............................................................................................5-1
1.1 How to Enter the Maintenance Mode.................................................................................5-1
1.2 How to Enter the End User-accessible Maintenance Mode .............................................. 5-1
1.3 List of Maintenance-mode Functions.................................................................................5-2
1.4 Detailed Description of Maintenance-mode Functions...................................................... 5-3
1.4.1 EEPROM Parameter Initialization (Function code 01, 91) ...................................... 5-3
1.4.2 Test Pattern (Function code 09) ..............................................................................5-4
1.4.3 Worker Switch (WSW) Setting and Printout ............................................................5-5
1.4.4 Operational Check of LCD (Function code 12)........................................................5-7
1.4.5 Operational Check of Control Panel PCB (Function code 13) ................................5-8
1.4.6 ROM Version Check (Function code 25).................................................................5-9
1.4.7 “One Push Demo” Setting (Function code 28) ......................................................5-10
1.4.8 Drum Unit Cleaning (Function code 31) ................................................................5-10
1.4.9 Operational Check of Sensors (Function code 32)................................................ 5-11
1.4.10 Printout of EEPROM Log (Function code 40)...................................................... 5-14
1.4.11 USB Transfer Speed Change in the PictBridge Mode (Function code 45) ......... 5-15
1.4.12 Adjustment of Color Registration (Function code 66)..........................................5-16
1.4.13 Paper Feeding and Ejecting Test (Function code 67)......................................... 5-18
1.4.14 Sensitivity Adjustment of Density Sensor (Function code 72) ............................ 5-18

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1.4.15 Sensitivity Adjustment of Registration-mark Sensor (Function code 75) ............ 5-19
1.4.16 Operational Check of Fans (Function code 78)................................................... 5-21
1.4.17 Display of the Machine’s Log (Function code 80)................................................ 5-23
1.4.18 Error Code Indication (Function code 82)............................................................ 5-26
1.4.19 Developing Bias Voltage Correction (Function code 83)..................................... 5-26
1.4.20 Exit from the Maintenance Mode (Function code 99).......................................... 5-26
2. OTHER SERVICE FUNCTIONS ...............................................................................5-27
2.1 Hidden Function Menus Enabled by Pressing Button(s) When Turning the
Machine On...................................................................................................................... 5-27
2.2 Develop Roller Counter Reset Function .......................................................................... 5-29
2.3 Printout of Printer Settings ............................................................................................... 5-30
2.4 How to Recover from Errors of the Fuser Unit................................................................. 5-35
2.5 How to Clear and Delete the Password for “Setting Lock” .............................................. 5-35
CHAPTER 6 CIRCUIT DIAGRAMS, WIRING DIAGRAM........................ 6-1
APPENDIX 1 WORKER SWITCH (WSW) ....................................... App.1-1
APPENDIX 2 DELETION OF PERSONAL INFORMATION............ App.2-1
APPENDIX 3 SERIAL NUMBERING SYSTEM ............................... App.3-1
APPENDIX 4 SCREW CATALOGUE .............................................. App.4-1
APPENDIX 5 HOW TO MAKE THE DRUM UNIT REMOVE SHEET ... App.5-1
APPENDIX 6 REFERENCES ........................................................... App.6-1

1-1
CHAPTER 1 TROUBLESHOOTING
1. INTRODUCTION
Troubleshooting is the countermeasure procedures that the service personnel should follow if
an error or malfunction occurs with the machine. It is impossible to anticipate all of the possible
troubles which may occur in future and determine the troubleshooting procedures, so this
chapter covers some sample troubles. However, those samples will help the service personnel
pinpoint and repair other defective elements.
1.1 Precautions
Be sure to observe and follow all the precautions to prevent any secondary problems from
happening during troubleshooting.
(1) Always turn off the power and unplug the power cable before removing any covers or
PCBs, adjusting the machine and so on. If you need to take voltage measurements with
the power switched on, take the greatest of care not to receive an electric shock.
(2) When connecting or disconnecting cable connectors, make sure that you hold the
connector body and not the cables.
(3) Electronic devices are sensitive to static build up; make sure that you touch a metal
portion of the machine to discharge yourself before accessing the PCBs.
Handle PCBs with care when repairing them.
Verify again that the repaired portion works properly.
1.2 Initial Check
Check the following items before attempting to repair the machine.
<Operating Environment>
(1) Put your machine on a flat, stable surface such as a desk that is free of vibration and
shocks.
(2) Use the machine in a well-ventilated room; use the machine within the following ranges of
temperature and humidity: temperature between 10°C and 32.5°C (50 °F to 90.5 °F), and
the relative humidity is maintained between 20% and 80%.
(3) Ensure the machine is not exposed to direct sunlight, excessive heat, moisture, or dust.
(4) Keep the machine horizontal when you carry it. To prevent injuries when moving or lifting
this machine, make sure to use at least two people.
Fig. 1-1

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2-31
(5) Assemble the MP lift arm 2 with aligning it with the three Bosses provided on the Front
door unit ASSY.
Note:
When assembling the MP lift arm 2, make sure that the shaft of the MP roller holder ASSY
is put into the hole on the MP lift arm 2.
Fig. 2-56
(6) Assemble the MP feed frame cover onto the Front door unit ASSY.
(7) Close the Front door unit ASSY.
Fig. 2-57
(8) After replacing the MP paper feeding kit, reset the counter. (Refer to “2.3 Parts Life Reset
Function” in this chapter.)
Front door unit ASSY
Hole
<Front side>
MP lift arm 2
Shaft
(MP roller holder ASSY)
Bosses
Hooks MP feed frame cover
Front door unit ASSY
<Front side>
Hook
Hook
MP feed frame cover

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2.3 Parts Life Reset Function
This function is provided for service personnel in order to reset the counter of each periodical
replacement part and count the number of replacement times when replacing the periodical
replacement parts.
Pressing the two buttons in the normal status
Panel Operation Function
Go & (+) Indicates the reset menu (“Reset Parts Life”)
(Resets the counter of the periodical replacement parts and
counts the number of replacement times.)
<Operating Procedure>
(1) Press the Go and buttons at the same time in the ready
status.
(2) The “Reset Parts Life” will appear on the LCD. Select the
applicable periodical replacement part by pressing the or
button and press the OK button.
< Periodical replacement parts are indicated on the LCD >
- Drum Unit - Belt Unit - PF KitMP - PF Kit1
- PF Kit2 - Fuser Unit - Laser Unit
(3) The “OK?” will appear on the LCD. Then, press the OK
button.
(4) The machine implements clearing the counter.
(5) The machine returns to the ready status.
Note:
- All periodical replacement parts are always indicated on the LCD even though their lives do
not reach 0 %.
- The PF kit2 is always indicated even though Tray 2 is not installed, or it is not supported for
the model to be used.
- The machine returns to the ready status automatically if no panel operation is implemented
for 30 seconds.

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3-1
CHAPTER 3 DISASSEMBLY AND ASSEMBLY
1. SAFETY PRECAUTIONS
To avoid creating secondary problems by mishandling, follow the warnings and precautions
below during maintenance work.
HOT SURFACE
Some parts inside the machine are extremely hot immediately after the machine is used.
When opening the front cover or back cover to access any parts inside the machine,
never touch the shaded parts shown in the following figures.
Caution:
- Be careful not to lose screws, washers, or other parts removed.
- Be sure to apply grease to the gears and applicable positions specified in this chapter.
- When using soldering irons or other heat-generating tools, take care not to accidentally
damage parts such as wires, PCBs and covers.
- Static electricity charged in your body may damage electronic parts. When transporting PCBs,
be sure to wrap them in conductive sheets.
- When replacing the PCB and all the other related parts, put on a grounding wrist band and
perform the job on a static mat. Also take care not to touch the conductor sections on the flat
cables or on the wire harness.
- After disconnecting flat cables, check that each cable is not damaged at its end or short-
circuited.
- When connecting flat cables, do not insert them at an angle. After insertion, check that the
cables are not at an angle.
- When connecting or disconnecting cable connectors, hold the connector body, not the cables.
If the connector has a lock, release the connector lock first to release it.
- After a repair, check not only the repaired portion but also all connectors. Also check that
other related portions are functioning properly before operational checks.