HP LaserJet Pro M521 Operating instructions

LASERJET PRO MFP
Repair Manual
M521
2

HP LaserJet Pro MFP M521 Printer
Repair Manual

Copyright and License
© 2012 Copyright Hewlett-Packard
Development Company, L.P.
Reproduction, adaptation, or translation
without prior written permission is
prohibited, except as allowed under the
copyright laws.
The information contained herein is subject
to change without notice.
The only warranties for HP products and
services are set forth in the express warranty
statements accompanying such products and
services. Nothing herein should be
construed as constituting an additional
warranty. HP shall not be liable for technical
or editorial errors or omissions contained
herein.
Edition 1, 12/2012
Part number: A8P79-90904
Trademark Credits
Adobe
®
, Acrobat
®
, and PostScript
®
are
trademarks of Adobe Systems Incorporated.
Microsoft®, Windows®, Windows® XP,
and Windows Vista® are U.S. registered
trademarks of Microsoft Corporation.
ENERGY STAR and the ENERGY STAR mark
are registered U.S. marks.

Conventions used in this guide
TIP: Tips provide helpful hints or shortcuts.
NOTE: Notes provide important information to explain a concept or to complete a task.
CAUTION: Cautions indicate procedures that you should follow to avoid losing data or damaging
the product.
WARNING! Warnings alert you to specific procedures that you should follow to avoid personal
injury, catastrophic loss of data, or extensive damage to the product.
ENWW iii

iv Conventions used in this guide ENWW

Table of contents
1 Removal and replacement ................................................................................................ 1
Removal and replacement strategy ............................................................................................. 2
General cautions during removal and replacement ........................................................ 2
Electrostatic discharge ............................................................................................... 2
Required tools ........................................................................................................... 3
Types of screws ........................................................................................................ 3
Service approach ..................................................................................................................... 5
Before performing service .......................................................................................... 5
After performing service ............................................................................................. 5
Post-service test ......................................................................................................... 5
Print-quality test .......................................................................................... 5
Location of connectors ............................................................................................... 7
DC controller connections ............................................................................ 7
Formatter connections ................................................................................. 9
Parts removal order ................................................................................................. 10
Removal and replacement procedures ...................................................................................... 11
Customer self repair (CSR) assemblies ....................................................................... 11
Toner cartridge ........................................................................................ 11
Tray 2 or Tray 3 assembly ......................................................................... 13
Document feeder rollers ............................................................................ 14
Document feeder pickup roller .................................................... 14
Document feeder separation roller ............................................... 16
Document feeder separation pad ............................................................... 17
External panels, covers, doors, and formatter ............................................................. 18
Formatter cover ........................................................................................ 18
Formatter PCA ......................................................................................... 19
Fax PCA and cable .................................................................................. 20
Interconnect board (ICB) ........................................................................... 21
Formatter stay .......................................................................................... 22
Dummy cover .......................................................................................... 23
Rear cover assembly ................................................................................. 24
Left cover ................................................................................................ 28
ENWW v

Right-rear cover ........................................................................................ 30
Tray 1 cover ............................................................................................ 32
Cartridge-door assembly ........................................................................... 34
Right cover assembly ................................................................................ 36
Lower right cover ..................................................................................... 41
Reinstall the lower right cover ..................................................... 43
I/O plate ................................................................................................ 44
Document feeder assemblies and scanner .................................................................. 46
Document feeder/scanner assembly ........................................................... 46
Document feeder whole unit kit and scanner whole unit kit ............................ 52
Document feeder hinge assembly ............................................................... 57
Control-panel top-cover ............................................................................. 57
Control-panel assembly ............................................................................. 59
USB PCA ................................................................................................ 60
Control-panel FFC .................................................................................... 61
USB cable and USB grounding cable ......................................................... 64
Wi-Fi module and cable ............................................................................ 67
Main assemblies ..................................................................................................... 71
Tray 1 pickup roller .................................................................................. 71
Tray 1 separation pad .............................................................................. 73
Tray 2 or Tray 3 pickup roller .................................................................... 74
Tray 2 or Tray 3 separation pad ................................................................ 76
Tray 2 or Tray 3 base-plate roller assembly ................................................. 76
Transfer roller .......................................................................................... 78
Fuser ...................................................................................................... 80
Duplex paper-feed assembly ...................................................................... 83
Registration roller assembly ....................................................................... 86
Power-switch assembly .............................................................................. 88
Interlock-switch assembly ........................................................................... 89
Tray sensor PCA ...................................................................................... 91
Main fan ................................................................................................. 93
Top cover ................................................................................................ 95
Laser scanner ........................................................................................... 98
Tag holder assembly ...............................................................................101
DC controller ......................................................................................... 102
Low-voltage power supply (LVPS) ..............................................................106
Tray 2 paper pickup assembly ................................................................. 112
Tray 1 or Tray 2 pickup solenoid ............................................................. 118
Fuser motor ........................................................................................... 120
Pendulum assembly ................................................................................ 121
Sub fan and fan duct .............................................................................. 124
vi ENWW

Environmental sensor .............................................................................. 128
High-voltage power supply (HVPS) ........................................................... 130
2 Parts and diagrams ...................................................................................................... 139
Order parts by authorized service providers ............................................................................ 140
Order parts, accessories, and supplies .................................................................... 140
Supplies part numbers ........................................................................................... 140
Customer self-repair (CSR) and service kits ............................................................... 141
Related documentation and software ...................................................................................... 142
Fasteners used in this product ................................................................................................ 142
How to use the parts lists and diagrams .................................................................................. 143
Assembly locations ............................................................................................................... 143
Base product (no optional trays or accessories) ......................................................... 143
Base product (optional trays or accessories) ............................................................. 144
Covers ................................................................................................................................ 146
Document feeder and scanner assemblies ............................................................................... 148
Control-panel and USB PCA assemblies .................................................................................. 150
Document feeder assemblies .................................................................................................. 152
Internal assemblies (1 of 6) ................................................................................................... 154
Internal assemblies (2 of 6) ................................................................................................... 156
Internal assemblies (3 of 6) ................................................................................................... 158
Internal assemblies (4 of 6) ................................................................................................... 160
Internal assemblies (5 of 6) ................................................................................................... 162
Internal assemblies (6 of 6) ................................................................................................... 164
Input devices ....................................................................................................................... 166
500-sheet input tray (Tray 3) .................................................................................. 166
Alphabetical parts list ........................................................................................................... 168
Numerical parts list .............................................................................................................. 172
Index ............................................................................................................................... 177
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viii ENWW

1 Removal and replacement
●Removal and replacement strategy
●Service approach
●Removal and replacement procedures
ENWW 1

Removal and replacement strategy
General cautions during removal and replacement
This chapter describes the removal and replacement of field-replaceable units (FRUs) only.
Replacing FRUs is generally the reverse of removal. Occasionally, notes and tips are included to
provide directions for difficult or critical replacement procedures.
HP does not support repairing individual subassemblies or troubleshooting to the component level.
WARNING! Turn the product off, wait 5 seconds, and then remove the power cable before
attempting to service the product. If this warning is not followed, severe injury can result, in addition to
damage to the product. The power must be on for certain functional checks during troubleshooting.
However, disconnect the power supply during parts removal.
Never operate or service the product with the protective cover removed from the laser scanner
assembly. The reflected beam, although invisible, can damage your eyes.
The sheet-metal parts can have sharp edges. Be careful when handling sheet-metal parts.
CAUTION: Do not bend or fold the flat flexible cables (FFCs) during removal or installation. Also, do
not straighten prefolds in the FFCs. You must fully seat all FFCs in their connectors. Failure to fully seat
an FFC into a connector can cause a short circuit in a PCA.
Incorrectly routed or loose wire harnesses can interfere with other internal components and can become
damaged or broken. Frayed or pinched harness wires can be difficult to find. When replacing wire
harnesses, always use the provided wire loops, lance points, or wire-harness guides and retainers.
NOTE: To install a self-tapping screw, first turn it counterclockwise to align it with the thread pattern,
and then carefully turn it clockwise to tighten. Do not overtighten. If a self-tapping screw-hole becomes
stripped, repair the screw-hole or replace the affected assembly.
Note the length, diameter, color, type, and location of each screw. Be sure to return each screw to its
original location during reassembly.
TIP: For clarity, some photos in this chapter might show components removed that would not be
removed to service the product. If necessary, remove the components listed at the beginning of a
procedure before proceeding to service the product.
Electrostatic discharge
CAUTION: Some parts are sensitive to electrostatic discharge (ESD). Look for the ESD reminder
when removing product parts. Always perform service work at an ESD-protected workstation or mat, or
use an ESD strap. If an ESD workstation, mat, or strap is not available, ground yourself by touching the
sheet-metal chassis before touching an ESD-sensitive part.
Protect the ESD-sensitive parts by placing them in ESD pouches when they are out of the product.
2 Chapter 1 Removal and replacement ENWW

Required tools
●#2 Phillips 152 mm (6 in) screwdriver with magnetic tip
●#2 Phillips 76 mm (3 in) screwdriver with magnetic tip
●Small flat-tip screwdriver
●Small needle-nose pliers
●ESD mat
●Penlight
CAUTION: Always use a Phillips screwdriver (callout 1). Do not use a Pozidriv® screwdriver
(callout 2) or any motorized screwdriver. These can damage screws or screw threads.
Figure 1-1 Phillips and Pozidriv screwdriver comparison
Types of screws
NOTE: The illustration in this section are for reference only. The screws in your product might look
slightly different.
Illustration Description Size Part number Use
Screw M3X6 0515-2908 Used to secure metal
components to metal
components (for
example, a ground
wire to the frame)
Screw M3X8 0515-4681
Screw, tapping P-M3X6 0515-5621
Screw, tapping, truss
head
M4X14 0515-4672 Used to secure
anything to plastic
ENWW Removal and replacement strategy 3

14 mm
4 Chapter 1 Removal and replacement ENWW

Service approach
Product repair normally begins by using the product internal diagnostics and the following two-step
process:
1. Isolate the problem to the major system (for example, the network, the server, or the product).
2. Troubleshoot the problem by using the procedures in the solve problems chapter of the
Troubleshooting Manual.
After you find a faulty part, the product can usually be repaired at the assembly level by replacing field-
replaceable units (FRUs). Some mechanical assemblies might need to be repaired at the subassembly
level.
Before performing service
●Remove all paper from the product.
●Turn off the power using the power switch.
●Disconnect the power cable and interface cable or cables.
●Place the product on an ESD workstation or mat, or use an ESD strap (if one is available). If an
ESD workstation, mat, or strap is not available, ground yourself by touching the sheet-metal
chassis before touching an ESD-sensitive part.
●Remove the toner cartridges. See Toner cartridge on page 11.
●Remove the tray or trays. See Tray 2 or Tray 3 assembly on page 13.
After performing service
●Connect the power cable.
●Reinstall the toner cartridges.
●Reinstall the tray or trays.
●If an optional paper feeder was installed, place the product on the feeder.
Post-service test
Perform the following test to verify that the repair or replacement was successful.
Print-quality test
1. Verify that you have completed the necessary reassembly steps.
2. Make sure that the tray contains clean, unmarked paper.
3. Attach the power cable and interface cable or interface cables, and then turn on the product.
4. Verify that the expected start-up sounds occur. The fans start.
ENWW Service approach 5

5. Print a configuration page, and then verify that the expected printing sounds occur. The fans start
and the rollers turn.
6. Print a demo page, and then verify that the print quality is as expected.
7. Send a print job from the host computer, and then verify that the output meets expectations.
8. If necessary, restore any customer-specified settings.
9. Clean the outside of the product with a damp cloth.
6 Chapter 1 Removal and replacement ENWW

Location of connectors
DC controller connections
Figure 1-2 DC controller connections
J2400
J2311
J2301
J2302
J2310
J2105
J2307
J2304
J2702
J2201
J2200
FT1
FT2
J2100 J2700
J2701
J2703
J2704
J2308 J2401 J2303
J2306
J2103J2104 J2102
Item Description Item Description Item Description
J2100 Not used J2302 MPT paper out
sensor (PS205)
J2400 Fuser output sensor
(PS2)
TH1/TH2
J2102 Fuser motor
(M8002)
J2303 Face-up sensor
(PS1)
Output bin full
sensor (PS4)
J2401
J2103 Main motor
(M8003)
J2304 Environmental
sensor (TH3)
J2700 LVPS
ENWW Service approach 7

Item Description Item Description Item Description
J2104 Subfan (FM2)
Rear door sensor
(PS8001)
Scanner motor
(M3)
J2306 Interlock-switch
(SW260)
J2701 LVPS
J2105 Power switch
(SW240)
J2307 Tray detection
switch (SW235)
J2702 LVPS
J2200 HVPS J2308 Main fan (FM1) J2703 Cartridge door switch
(SW501)
J2201 Paper feeder
connector
J2310 CST pickup
solenoid (SL2)
J2704 Cartridge door switch
(SW501)
J2301 CST paper out
sensor (PS3)
J2311 MPT pickup
solenoid (SL1)
8 Chapter 1 Removal and replacement ENWW

Formatter connections
Figure 1-3 Formatter connections
J16 USB DEVICE
J8 LAN
TAZ
J24 SNAPPER FAX
J7
POWER
J27
J3
J20
SCANNER
J19
J18 WIFI
J17 THUMB
J22 ADF MOTOR
J21 ADF SCAN
Item Description Item Description
J3 Control panel J19 Flatbed scanner
J7 Power J20 Flatbed motor
J8 LAN J21 ADF/Scanner
J16 USB Device J22 ADF motor
J17 USB J24 Snapper Fax
J18 Wifi J27 Video
ENWW Service approach 9

Parts removal order
Figure 1-4 Parts removal order: covers and customer-replaceable assemblies
Assembly Remove Remove Remove Remove Remove
Toner cartridge
Tray2,3
Formatter cover
Formatter PCA
ICB
Fax card and cable
Dummy cover
Formatter cover
Rear cover assy
Left cover
Right-rear cover
Tray 1 cover
Cartridge-door assy
Right cover
Lower right cover
Top cover
I/O Plate
ADF pickup &
separation roller
Control Panel
sub cover
USB PCA
Control Panel
FFC cable
Formatter cover
Formatter cover
Formatter cover
Rear cover assy
Formatter cover
Rear cover assy
1. covers and customer replaceable assemblies
Formatter cover
Dummy cover
Rear cover assy
Left cover
Rear cover assy
Left cover Tray 1 cover
Tray 1 cover
(could choose
not remove)
Cartridge-door assy
(could choose not
remove, only open)
Assembly Remove Remove Remove Remove
Control Panel
top cover
2. ADF/Scanner assembly
Scanner whole unit
ADF whole unit
Wifi module
and cable
USB cable &
grounding cable
Control Panel
top cover
Control Panel Control Panel
top cover Control Panel sub cover
Control Panel
top cover
Formatter cover
Dummy cover
Rear cover assy
Left cover
ADF/Scanner
assy
USB bracket
(sheet metal)
Scanner lower
cover Control Panel top cover Control Panel sub cover
Scanner lower
cover Control Panel top cover
Scanner lower
cover
Scanner rear
cover
Scanner rear
cover
ADF hinge assembly
Tray 1
separation pad
Tray 2, 3
separation pad
Tray 2, 3 base-plate
roller assy
Assembly Remove Remove Remove Remove Remove
Tray 1 pickup roller
3. Main assemblies
Registration roller
assy
Duplex media-feed
assy
Fuser
Transfer roller
Tray 2, 3
pickup roller
Power-switch assy
Rear cover assy Right-rear cover
Rear cover assy
Right-rear cover
Rear cover assy Left cover
Formatter cover
Dummy cover
Rear cover assy
Left cover
Right-rear cover
Tray 1 cover
Cartridge-door
assy
Interlock switch assy
Tray sensor PCA
Main fan
DC controller
Top cover
Laser scanner
Tag holder assy
Tray 1 cover
Tray 1 cover
Tray 1 cover
Tray 1 cover
Tray 1 cover
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
LVPS (Low-voltage
power supply)
Tray 1, 2 pickup
solenoid
Fuser motor
Pendulum assy
Sub fan and
fan duct
Environmental
sensor
Tray 2 paper pickup
HVPS
Formatter cover
Dummy cover
Rear cover assy
Left cover
Right cover
Right cover
Right cover
Right cover
Right cover
Right cover
Duplex media-feed
assy
Duplex media-feed
assy
Cartridge-door assy
Cartridge-door assy
Cartridge-door assy
Cartridge-door assy
Cartridge-door assy
Right cover
Right cover
Right cover
Right cover
Right cover Lower right cover
(if removing sheet
metal plate)
Top cover
Top cover
Lower right cover
Lower right cover
Lower right cover
Lower right cover
Lower right cover
Lower right cover
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
Top cover
Top cover
Top cover
Top cover
Top cover
Top cover
Right cover
Right cover
Lower right cover
Lower right cover
ADF/Scanner assy
ADF/Scanner assy
Top cover
Top cover
DC controller
DC controller
LVPS
LVPS
DC controller LVPS Fuser motor
DC controller
DC controller
with plate
DC controller
DC controller
DC controller
LVPS
LVPS
LVPS
LVPS
LVPS
Remove Remove Remove
Formatter cover
ADF/Scanner assy
ADF/Scanner assy
ADF/Scanner assy
Right cover
Formatter PCA
ICB
Fax card
Formatter Stay
(sheet metal)
I/O Plate assembly
10 Chapter 1 Removal and replacement ENWW