HP PageWide Enterprise Color 765, PageWide Enterprise Color 780, PageWide Enterprise Color 785 Troubleshooting Manual

4.5 (6)

HP PageWide Enterprise Color 765 and MFP 780/785

HP PageWide Managed Color E75160 and MFP E77650/P77660

Troubleshooting Manual

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, 9/2017

Trademark Credits

Microsoft®, Windows®, Windows® XP, and Windows Vista® are U.S. registered trademarks of Microsoft Corporation.

Adobe®, Acrobat®, and PostScript® are trademarks of Adobe Systems Incorporated.

UNIX® is a registered trademark of The Open Group.

Conventions used in this guide

TIP: Helpful hints or shortcuts.

NOTE: Information that explains a concept or how to complete a task.

Reinstallation tip: Reinstallation helpful hints, shortcuts, or considerations.

IMPORTANT: Information that help the user to avoid potential printer error conditions.

CAUTION: Procedures that the user must follow to avoid losing data or damaging the printer.

WARNING! Procedures that the user must follow to avoid personal injury, catastrophic loss of data, or extensive damage to the printer.

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Conventions used in this guide

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For additional service and support information

HP service personnel, go to one of the following Web-based Interactive Search Engines (WISE) sites:

AMS

●https://support.hp.com/wise/home/ams-en

●https://support.hp.com/wise/home/ams-es

●https://support.hp.com/wise/home/ams-pt

APJ

●https://support.hp.com/wise/home/apj-en

●https://support.hp.com/wise/home/apj-ja

●https://support.hp.com/wise/home/apj-ko

●https://support.hp.com/wise/home/apj-zh-Hans

●https://support.hp.com/wise/home/apj-zh-Hant

EMEA

●https://support.hp.com/wise/home/emea-en

Channel partners, go to HP Channel Services Network (CSN) at www.hp.com/partners/csn .

At these locations, nd information on the following topics:

●Install and con gure

●Printer speci cations

●Up-to-date control panel message (CPMD) troubleshooting

●Solutions for printer issues and emerging issues

●Remove and replace part instructions and videos

●Service advisories

●Warranty and regulatory information

Channel partners, access training materials in the HP University and Partner Learning Center at https://content.ext.hp.com/sites/LMS/HPU.page.

To access HP PartSurfer information from any mobile device, go to http://partsurfermobile.hp.com/ or scan the Quick Response (QR) code below.

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For additional service and support information

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Table of contents

1 Theory of operation ..................................................................................................................................................................................	1
Basic operation .........................................................................................................................................................................	2
Function structure ...............................................................................................................................................	2
Operation sequence ............................................................................................................................................	4
System control ..........................................................................................................................................................................	6
.................................................................................................................................................................................	6
Formatter and data path ....................................................................................................................................	6
Engine control ......................................................................................................................................................	8
Pen interface (I/F) ..............................................................................................................................................	10
Power supply ......................................................................................................................................................	11
AC control module .............................................................................................................................................	11
Cabling system .......................................................................................................................................................................	13
Flat Flexible Cables ...........................................................................................................................................	13
FFC routing ..........................................................................................................................................................	16
Discrete cables ...................................................................................................................................................	19
Ground wires ......................................................................................................................................................	20
Connectors ..........................................................................................................................................................	21
Ferrites ................................................................................................................................................................	23
Cable management ...........................................................................................................................................	23
Print subsystem .....................................................................................................................................................................	25
Printhead ............................................................................................................................................................	25
Printhead air management system ................................................................................................................	26
Printhead lift .......................................................................................................................................................	26
Print cartridges ..................................................................................................................................................	26
Optical scan carriage .........................................................................................................................................	26
Print system operational states ......................................................................................................................	26
Paper-handling system .........................................................................................................................................................	29
Printer sensors ...................................................................................................................................................	29
High Capacity Input (HCI) sensors ...................................................................................................................	30
3x550 tray sensors ...........................................................................................................................................	31
1x550 tray sensors ...........................................................................................................................................	32
Inline nisher sensors .......................................................................................................................................	33

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Printer motors/solenoids .................................................................................................................................	34
High capacity input (HCI) motors/solenoids ..................................................................................................	35
3x550 tray motors/solenoids ..........................................................................................................................	36
1x550 tray motors/solenoids ..........................................................................................................................	37
Inline nisher motors ........................................................................................................................................	38
Printer printing system .....................................................................................................................................	39
Input trays ...........................................................................................................................................................	40
Paper path zones ...............................................................................................................................................	43
Jam detection .....................................................................................................................................................	45
Servicing system ....................................................................................................................................................................	48
Printhead wiper ..................................................................................................................................................	48
Service fluid and aerosol management systems .............................................................................................................	49
irflow system ........................................................................................................................................................................	51
Function ..............................................................................................................................................................	51
Heating ................................................................................................................................................................	51
irflow .................................................................................................................................................................	51
Modes ..................................................................................................................................................................	51
Components .......................................................................................................................................................	52
Document feeder system .....................................................................................................................................................	53
Document feed system ....................................................................................................................................	53
Sensors in the document feeder ....................................................................................................................	53
Document feeder paper path ..........................................................................................................................	54
Document feeder simplex operation .............................................................................................................	55
Document feeder e-duplex operation ...........................................................................................................	56
Deskew operation .............................................................................................................................................	57
Document feeder hinges ..................................................................................................................................	57
Scanning and image capture system (780/785) ..............................................................................................................	59
Fax functions and operation .................................................................................................................................................	60
Computer and network security features .....................................................................................................	60
PSTN operation ..................................................................................................................................................	60
The fax subsystem ............................................................................................................................................	60
Fax card in the fax subsystem .........................................................................................................................	60
Fax page storage in flash memory .................................................................................................................	62
Output accessories ................................................................................................................................................................	63
Inline nisher ......................................................................................................................................................	64
2 Solve problems .......................................................................................................................................................................................	91
Problem-solving checklist ....................................................................................................................................................	92
Step 1: Check that the printer power is on ....................................................................................................	92
Step 2: Check the control panel for error messages ...................................................................................	92
Step 3: Test print functionality ........................................................................................................................	93

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Step 4: Test copy functionality (MFP models only) ......................................................................................	93
Step 5: Test the fax sending functionality (785f/785zs/785z+) ...............................................................	94
Step 6: Test the fax receiving functionality (fax models only) ...................................................................	94
Step 7: Try sending a print job from a computer .........................................................................................	94
Step 8: Test the Plug and Print USB Drive printing functionality ...............................................................	94
Factors that a ect printer performance ........................................................................................................	94
Troubleshooting process ......................................................................................................................................................	96
Determine the problem source .......................................................................................................................	96
Power subsystem ..............................................................................................................................................	98
Tools for troubleshooting ...................................................................................................................................................	129
Print the con guration and printhead information pages ........................................................................	129
Event log messages ........................................................................................................................................	132
Tools for troubleshooting: Individual component diagnostics ................................................................	133
Diagrams ..........................................................................................................................................................	146
Print-quality troubleshooting tools ..............................................................................................................	159
Control panel menus ......................................................................................................................................	168
Control panel message document (CPMD) .................................................................................................	243
Print quality troubleshooting guide ..................................................................................................................................	244
Printer pre-checks ..........................................................................................................................................	244
Printer speci c image defects .......................................................................................................................	258
Solve copy/scan problems (780/785) ..............................................................................................................................	297
Solve copy problems (780/785 models only) ............................................................................................	297
Solve scan problems (780/785 models only) ............................................................................................	302
Solve paper jam or feed problems ...................................................................................................................................	308
Printer does not pick up paper or misfeeds ................................................................................................	308
Clear paper jams .............................................................................................................................................	310
Solve performance problems ............................................................................................................................................	340
Factors a ecting print performance ............................................................................................................	340
The printer does not print or it prints slowly ..............................................................................................	341
The printer prints slowly ................................................................................................................................	342
Solve connectivity problems ..............................................................................................................................................	343
Solve USB connection problems ...................................................................................................................	343
Solve wired network problems .....................................................................................................................	343
Service mode functions ......................................................................................................................................................	345
Service menu ...................................................................................................................................................	345
Printer resets ...................................................................................................................................................	354
Format Disk and Partial Clean functions .....................................................................................................	356
Firmware upgrades .............................................................................................................................................................	359
Determine the installed revision of rmware .............................................................................................	359
Perform a rmware upgrade ........................................................................................................................	361
Solve fax problems ..............................................................................................................................................................	365

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Solve email problems .........................................................................................................................................................	366
Appendix A Printer speci cations .........................................................................................................................................................	367
Printer dimensions and weight .........................................................................................................................................	368
Printer space requirements ...............................................................................................................................................	369
Power consumption, electrical speci cations, and acoustic emissions ......................................................................	369
Operating-environment range ..........................................................................................................................................	370
Certi cate of Volatility .........................................................................................................................................................	371
Index ...........................................................................................................................................................................................................	415

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List of tables

Table 1-1	Operation sequence ................................................................................................................................................................	4
Table 1-2	Printbar components ............................................................................................................................................................	25
Table 1-3 Service Fluid and Aerosol Management System Components ......................................................................................		50
Table 1-4 Document feeder sensors ...................................................................................................................................................		54
Table 1-5 Document feeder paper path ..............................................................................................................................................		54
Table 2-1	Troubleshooting flowchart ..................................................................................................................................................	97
Table 2-2	MPCA LEDs ...........................................................................................................................................................................	100
Table 2-3 MPCA LED sequence at printer power on .......................................................................................................................		100
Table 2-4	MPCA LEDs ...........................................................................................................................................................................	133
Table 2-5 MPCA LED sequence at printer power on .......................................................................................................................		134
Table 2-6	ACCM LEDs ...........................................................................................................................................................................	135
Table 2-7 ACCMA LED sequence at printer power on .....................................................................................................................		135
Table 2-8 Heartbeat LED, product initialization ...............................................................................................................................		136
Table 2-9 Heartbeat LED, product operational ................................................................................................................................		139
Table 2-10	Reports menu ...................................................................................................................................................................	169
Table 2-11	Settings menu ...................................................................................................................................................................	171
Table 2-12 Copy menu (MFP only) .....................................................................................................................................................		197
Table 2-13 Scan menu (780/785) .....................................................................................................................................................		203
Table 2-14 Fax menu (fax models only) ...........................................................................................................................................		231
Table 2-15 Print Options menu ..........................................................................................................................................................		235
Table 2-16	Supplies menu ..................................................................................................................................................................	236
Table 2-17	Trays menu ........................................................................................................................................................................	237
Table 2-18	Backup/Restore menu .....................................................................................................................................................	238
Table 2-19	Calibrate/Cleaning menu .................................................................................................................................................	238
Table 2-20	Troubleshooting menu ....................................................................................................................................................	240
Table 2-21 Printhead health score ....................................................................................................................................................		251
Table 2-22 Solve performance problems .........................................................................................................................................		340
Table 2-23	Service menu ....................................................................................................................................................................	345
Table A-1 Dimensions for printer base model (SFP; all) .................................................................................................................		368
Table A-2 Dimensions for base models (780dn, 785f; MFP) .........................................................................................................		368
Table A-3 Dimensions for 785zs (MFP) .............................................................................................................................................		368
Table A-4 Dimensions for the 1x550-sheet paper feeder .............................................................................................................		368

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Table A-5	Dimensions for the 1x550-sheet paper feeder with stand .........................................................................................	369
Table A-6	Dimensions for the 3x550-sheet paper feeder with stand .........................................................................................	369
Table A-7	Dimensions for the 4,000-sheet HCI with stand ...........................................................................................................	369
Table A-8	Operating-environment speci cations ............................................................................................................................	370

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List of gures

Figure 1-3 FFC insertion line .................................................................................................................................................................		13
Figure 1-4 FFC support tape .................................................................................................................................................................		14
Figure 1-5	FFC label ................................................................................................................................................................................	14
Figure 1-6 FFC wing feature ..................................................................................................................................................................		15
Figure 1-7	ZIF connector ........................................................................................................................................................................	15
Figure 1-8 FFC hook arm retainers ......................................................................................................................................................		16
Figure 1-9 FFC pill bump retainers .......................................................................................................................................................		17
Figure 1-10 FFC die-cut retainers ........................................................................................................................................................		18
Figure 1-11 FFC double-sided tape retainer ......................................................................................................................................		18
Figure 1-12 Discrete cable ferrite ........................................................................................................................................................		19
Figure 1-13 Discrete cable tie-wraps ..................................................................................................................................................		20
Figure 1-14	Ground wires ......................................................................................................................................................................	21
Figure 1-16 FFC wing feature ...............................................................................................................................................................		22
Figure 1-17	ZIF connector .....................................................................................................................................................................	23
Figure 1-18	FFC spacing ........................................................................................................................................................................	24
Figure 1-19	Printhead components .....................................................................................................................................................	25
Figure 1-20 Print engine sensors .........................................................................................................................................................		29
Figure 1-21	HCI sensors ........................................................................................................................................................................	30
Figure 1-22 3x550 Tray sensors ..........................................................................................................................................................		31
Figure 1-23 1x550 tray sensors ...........................................................................................................................................................		32
Figure 1-24	Inline nisher sensors .......................................................................................................................................................	33
Figure 1-25	HCI motors/solenoids .......................................................................................................................................................	35
Figure 1-26 3x550 tray motors/solenoids .........................................................................................................................................		36
Figure 1-27 1x550 tray motors/solenoids .........................................................................................................................................		37
Figure 1-28	Inline nisher motors ........................................................................................................................................................	38
Figure 1-29 Printer printing system ....................................................................................................................................................		39
Figure 1-30 Tray 1 pick and separation system ................................................................................................................................		40
Figure 1-31 Service fluid and aerosol management system ..........................................................................................................		50
Figure 1-32 irflow system components ...........................................................................................................................................		52
Figure 1-33 Document feeder sensors ...............................................................................................................................................		54
Figure 1-34 Document feeder paper path ..........................................................................................................................................		54
Figure 1-35	Deskew operation .............................................................................................................................................................	57

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Figure 1-36 Document feeder open (book mode) ............................................................................................................................			58
Figure 1-37 Document feeder open (60º to 80º) ..............................................................................................................................			58
Figure 1-38 FFC insertion line ...............................................................................................................................................................			67
Figure 1-39 FFC support tape ...............................................................................................................................................................			68
Figure 1-40	FFC label .............................................................................................................................................................................		68
Figure 1-41 FFC hook arm retainers ....................................................................................................................................................			69
Figure 1-42 FFC pill bump retainers ....................................................................................................................................................			70
Figure 1-43 FFC die-cut retainers ........................................................................................................................................................			71
Figure 1-44 FFC double-sided tape retainer ......................................................................................................................................			71
Figure 1-45 Discrete cable ferrite ........................................................................................................................................................			72
Figure 1-46 Discrete cable tie-wraps ..................................................................................................................................................			73
Figure 1-47	Connectors .........................................................................................................................................................................		74
Figure 1-48	FFC spacing ........................................................................................................................................................................		75
Figure 1-49	Inline	nisher control diagram (front) ............................................................................................................................	76
Figure 1-50	Inline	nisher sensor control diagram (front) ...............................................................................................................	77
Figure 1-51	Inline	nisher motor control diagram (front) ................................................................................................................	78
Figure 1-52	Inline	nisher sensor diagram (1 of 2) ...........................................................................................................................	79
Figure 1-53	Inline	nisher sensor diagram (2 of 2) ...........................................................................................................................	80
Figure 1-54	Inline	nisher motor diagram ..........................................................................................................................................	81
Figure 1-55	Inline	nisher stapler control diagram ...........................................................................................................................	82
Figure 1-56	Inline	nisher stapler sensor diagram ...........................................................................................................................	83
Figure 1-57	Inline	nisher stapler motor control diagram ...............................................................................................................	84
Figure 2-1	MPCA LEDs .........................................................................................................................................................................		100
Figure 2-2 Formatter heartbeat LED .................................................................................................................................................			101
Figure 2-3 Diagnostic-tests access button (765 printers) .............................................................................................................			104
Figure 2-4 Diagnostic-tests access button (780/785 printers) ....................................................................................................			104
Figure 2-5 Press the diagnostics-access button (780/785 printers) ...........................................................................................			105
Figure 2-6 Control panel version A yellow screen ...........................................................................................................................			105
Figure 2-7 Exit the diagnostic mode .................................................................................................................................................			107
Figure 2-8 Open the Pre-boot menu .................................................................................................................................................			108
Figure 2-9	Pre-boot menu ..................................................................................................................................................................		109
Figure 2-10 Access the administration menu ..................................................................................................................................			110
Figure 2-11 Access the diagnostics menu ........................................................................................................................................			110
Figure 2-12 Open the screen test ......................................................................................................................................................			111
Figure 2-13 Blue vertical gradient screen ........................................................................................................................................			111
Figure 2-14 Open the touch test ........................................................................................................................................................			115
Figure 2-15 Touch the white grid .......................................................................................................................................................			115
Figure 2-16 Verify the mark ...............................................................................................................................................................			116
Figure 2-17 Open the softkey test ....................................................................................................................................................			117
Figure 2-18	Select Home ....................................................................................................................................................................		117
Figure 2-19	Successful test ................................................................................................................................................................		118

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Figure 2-20 Open the backlight test ..................................................................................................................................................			119
Figure 2-21 Open the sound test .......................................................................................................................................................			120
Figure 2-22 Open the keyboard test .................................................................................................................................................			121
Figure 2-23 Open the sound test .......................................................................................................................................................			122
Figure 2-24 Touchscreen blank, white, or dim (no image) ............................................................................................................			124
Figure 2-25 Touchscreen has an unresponsive zone .....................................................................................................................			125
Figure 2-26 No control panel sound ..................................................................................................................................................			126
Figure 2-27 Home key is unresponsive ............................................................................................................................................			127
Figure 2-28 Hardware integration pocket (HIP) is not functioning (control panel functional) ................................................			128
Figure 2-29	Con guration page .........................................................................................................................................................		129
Figure 2-30 Printhead information page ..........................................................................................................................................			131
Figure 2-31	MPCA LEDs .......................................................................................................................................................................		133
Figure 2-32	ACCM LEDs .......................................................................................................................................................................		135
Figure 2-33 Defeating interlocks (cartridge door) ..........................................................................................................................			141
Figure 2-34 Defeating interlocks (left door) ....................................................................................................................................			142
Figure 2-35 Defeating interlocks (right door) ..................................................................................................................................			142
Figure 2-36 Plug/jack locations (external printer) ..........................................................................................................................			146
Figure 2-37 Print engine sensors ......................................................................................................................................................			148
Figure 2-38	HCI sensors ......................................................................................................................................................................		149
Figure 2-39 3x550 tray sensors ........................................................................................................................................................			150
Figure 2-40 1x550 tray sensors ........................................................................................................................................................			151
Figure 2-41	Inline nisher sensors ....................................................................................................................................................		152
Figure 2-42	Printer motors/solenoids ..............................................................................................................................................		153
Figure 2-43	HCI motors/solenoids .....................................................................................................................................................		154
Figure 2-44 3x550 tray motors/solenoids .......................................................................................................................................			155
Figure 2-45 1x550 tray motors/solenoids .......................................................................................................................................			156
Figure 2-46	Inline nisher motors .....................................................................................................................................................		157
Figure 2-47 Printer printing system ..................................................................................................................................................			158
Figure 2-50	Ink smear/redeposit .......................................................................................................................................................		255
Figure 2-51 Print Quality Report page ..............................................................................................................................................			260
Figure 2-52 Print Head Diagnostic Page ...........................................................................................................................................			262
Figure 2-53 Printhead Details page ..................................................................................................................................................			264
Figure 2-67 Paper jam locations (765) .............................................................................................................................................			310
Figure 2-68 Paper jam locations (780/785) ....................................................................................................................................			312
Figure 2-69 Open the Pre-boot menu ..............................................................................................................................................			355
Figure 2-70 Open the Pre-boot menu ..............................................................................................................................................			357
Figure 2-71 Open the Pre-boot menu ..............................................................................................................................................			358
Figure 2-72	Determine the installed revision of rmware ............................................................................................................		360
Figure 2-73 Open the Pre-boot menu ..............................................................................................................................................			363
Figure A-1	Certi	cate of Volatility (750dn; 1 of 3) ...........................................................................................................................	371
Figure A-2	Certi	cate of Volatility (750dn; 2 of 3) ...........................................................................................................................	372

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Figure A-3	Certi	cate of Volatility (750dn; 3 of 3) ...........................................................................................................................		373
Figure A-4	Certi	cate of Volatility (750dw; 1 of 4) ..........................................................................................................................		374
Figure A-5	Certi	cate of Volatility (750dw; 2 of 4) ..........................................................................................................................		375
Figure A-6	Certi	cate of Volatility (750dw; 3 of 4) ..........................................................................................................................		376
Figure A-7	Certi	cate of Volatility (750dw; 4 of 4) ..........................................................................................................................		377
Figure A-8	Certi	cate of Volatility (772dn; 1 of 3) ...........................................................................................................................		378
Figure A-9	Certi	cate of Volatility (772dn; 2 of 3) ...........................................................................................................................		379
Figure A-10	Certi		cate of Volatility (772dn; 3 of 3) ........................................................................................................................	380
Figure A-11	Certi		cate of Volatility (772dw; 1 of 4) ........................................................................................................................	381
Figure A-12	Certi		cate of Volatility (772dw; 2 of 4) ........................................................................................................................	382
Figure A-13	Certi		cate of Volatility (772dw; 3 of 4) ........................................................................................................................	383
Figure A-14	Certi		cate of Volatility (772dw; 4 of 4) ........................................................................................................................	384
Figure A-15	Certi		cate of Volatility (777z; 1 of 4) ...........................................................................................................................	385
Figure A-16	Certi		cate of Volatility (777z; 2 of 4) ...........................................................................................................................	386
Figure A-17	Certi		cate of Volatility (777z; 3 of 4) ...........................................................................................................................	387
Figure A-18	Certi		cate of Volatility (777z; 4 of 4) ...........................................................................................................................	388
Figure A-19	Certi		cate of Volatility (75050dn; 1 of 3) ....................................................................................................................	389
Figure A-20	Certi		cate of Volatility (75050dn; 2 of 3) ....................................................................................................................	390
Figure A-21	Certi		cate of Volatility (75050dn; 3 of 3) ....................................................................................................................	391
Figure A-22	Certi		cate of Volatility (75050dw; 1 of 4) ...................................................................................................................	392
Figure A-23	Certi		cate of Volatility (75050dw; 2 of 4) ...................................................................................................................	393
Figure A-24	Certi		cate of Volatility (75050dw; 3 of 4) ...................................................................................................................	394
Figure A-25	Certi		cate of Volatility (75050dw; 4 of 4) ...................................................................................................................	395
Figure A-26	Certi		cate of Volatility (77740dn; 1 of 3) ....................................................................................................................	396
Figure A-27	Certi		cate of Volatility (77740dn; 2 of 3) ....................................................................................................................	397
Figure A-28	Certi		cate of Volatility (77740dn; 3 of 3) ....................................................................................................................	398
Figure A-29	Certi		cate of Volatility (77740dw; 1 of 4) ...................................................................................................................	399
Figure A-30	Certi		cate of Volatility (77740dw; 2 of 4) ...................................................................................................................	400
Figure A-31	Certi		cate of Volatility (77740dw; 3 of 4) ...................................................................................................................	401
Figure A-32	Certi		cate of Volatility (77740dw; 4 of 4) ...................................................................................................................	402
Figure A-33	Certi		cate of Volatility (77740z; 1 of 4) ......................................................................................................................	403
Figure A-34	Certi		cate of Volatility (77740z; 2 of 4) ......................................................................................................................	404
Figure A-35	Certi		cate of Volatility (77740z; 3 of 4) ......................................................................................................................	405
Figure A-36	Certi		cate of Volatility (77740z; 4 of 4) ......................................................................................................................	406
Figure A-37	Certi		cate of Volatility (77750z; 1 of 4) ......................................................................................................................	407
Figure A-38	Certi		cate of Volatility (77750z; 2 of 4) ......................................................................................................................	408
Figure A-39	Certi		cate of Volatility (77750z; 3 of 4) ......................................................................................................................	409
Figure A-40	Certi		cate of Volatility (77750z; 4 of 4) ......................................................................................................................	410
Figure A-41	Certi		cate of Volatility (77760z; 1 of 4) ......................................................................................................................	411
Figure A-42	Certi		cate of Volatility (77760z; 2 of 4) ......................................................................................................................	412
Figure A-43	Certi		cate of Volatility (77760z; 3 of 4) ......................................................................................................................	413

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Figure A-44 Certi cate of Volatility (77760z; 4 of 4) ......................................................................................................................

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1Theory of operation

●Basic operation

●System control

●Cabling system

●Print subsystem

●Paper-handling system

●Servicing system

●Service fluid and aerosol management systems

●irflow system

●Document feeder system

●Scanning and image capture system (780/785)

●Fax functions and operation

●Output accessories

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HP PageWide Enterprise Color 765, PageWide Enterprise Color 780, PageWide Enterprise Color 785 Troubleshooting Manual

Basic operation

Function structure

HP recommends printing the following document (on A3 size paper) for troubleshooting reference. It is available on the HP Web-based Interactive Search Engines (WISE). See HP Web-based Interactive Search Engines (WISE) on page 3.

Figure 1-1 Printer printing system

Legend	VentSolenoid	S	PumpFluid	PumpFluidMotor
Legend		N
		N

Motor

Fan/Digital Tach F

Solenoid N S

Opto Sensor

Reflective REDI

Other Sensors Pinch roller

Retard Roller Star Wheel

Switch/Hall

Effect Sensor

Torque Coupling

Media Path

12.13mm Dia

16.17mm Dia PTO connection

150 LPI, 1200 Line

Digital Encoder

Acumen

Level Sensors		Air Pump
Fluid
Fluid

Printhead Assembly

Pinch 1

Ejection

	Assembly	F	Motor
		AirflowFan
Left Vertical Pinch 2	Airflow	AirflowFan
	Airflow

Image Sensor Carriage Motor

Duplex Pinch 5

Air Pump Motor

Printhead Wiper Motor

Duplex

Pinch 4

Printhead Lift

Motor

Printhead Lift Encoder

Printhead Lift Sensor

Duplex

Pinch 3

Output Pinch 1

Drop Detect Carriage Motor

Output Pinch 3 Output Pinch 2

Airflow Heater

Airflow Assembly Thermistor

Aerosol Fan Motor

Duplex

inch1

Roller

Tray 3 Pick

Sheet 500 Tray 3

Roller

Tray 2 Pick

Duplex Pinch 2	500 Sheet Tray 2
Tray 1 Separation Pinch

2 Chapter 1 Theory of operation

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HP Web-based Interactive Search Engines (WISE)

The printer print system document is available on the HP Web-based Interactive Search Engines (WISE). Go to the appropriate Web site (listed below), and then search information by printer name.

NOTE: Make sure that this document is printed on A3 size paper.

AMS

●https://support.hp.com/wise/home/ams-en

●https://support.hp.com/wise/home/ams-es

●https://support.hp.com/wise/home/ams-pt

APJ

●https://support.hp.com/wise/home/apj-en

●https://support.hp.com/wise/home/apj-ja

●https://support.hp.com/wise/home/apj-ko

●https://support.hp.com/wise/home/apj-zh-Hans

●https://support.hp.com/wise/home/apj-zh-Hant

EMEA

●https://support.hp.com/wise/home/emea-en

ENWW	Basic operation 3

Operation sequence

The engine-control system on the main printed circuit board MPCA controls the operational sequences. The following table describes the durations and the operations for each period of a print operation from when the printer is turned on to when the motors stop rotating.

Table 1-1 Operation sequence

Period	Duration	Purpose

Initial startup and	When the printer is set up for the	This one-time setup process gets the printer ready to print for the rst
calibrations	rst time from the factory.	time.
	NOTE: Startup is disabled if the	●	Fluid replacement—The printer flushes the shipping and
	temperature is 5°C (41°F) or		handling fluid out of the printhead and replaces it with ink. No
	lower. The recommend		pages are printed.
	temperature range for this	●
	function is 15°C (59°F) to 40°C	●	Pen energy calibration (TTOE)—No pages are printed.
	(104°F).	●	Die alignment—The printer aligns the 14 die on the printhead
		●
			active face, and then prints and internally analyzes one page.
		●	Die density leveling—The printer measures and compensates
			for the drop variation, and then prints and internally analyzes
			multiple pages.

Servicing operations	Performed just before the	Servicing maintains print quality by removing debris and excess ink.
	printhead enters the capped	Nozzle presence detection is employed to replace missing nozzles.
	state after printing, when leaving	●
	the capped state after a print job	●	Nozzle presence detection—The optical scan carriage detects
	is initiated, or during printer idle		and disables inoperable nozzles, and replaces them with
	times when a print job is not		operable nozzles.
	impacted.	●	Printhead servicing—The web wipe on the printhead wiper
		●	Printhead servicing—The web wipe on the printhead wiper

moves under the printhead to clean the active face and res the nozzles into the ink collection unit to clear clogged or blocked nozzles.

Print preparation	From the time the printer
	receives a print command until
	paper enters the print zone.

Prepares the printer for a print job.

●The printhead leaves the capping state as the printhead wiper moves away from the printhead.

●If needed, some servicing occurs.

●The printhead lowers to the printing position. The media type and printing mode determine the print zone height.

●The printer picks paper from one of the input trays.

●Every page from Tray 1 is measured for edge detection. For Tray 2/3 and optional Trays 3, 4 and 5, the printer performs media

edge detection after printing the rst sheet. The last sheet of each job is also measured for edge detection if at least ve sheets have been printed.

●The printer monitors environmental conditions. The printer can

slow the print speed if conditions are signi cantly di erent from a normal office environment (23°C (73.4°F), 50% relative humidity).

●The formatter PCA processes print data and transmits the data to the printhead.

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Table 1-1 Operation sequence (continued)

Period	Duration	Purpose

Printing	From the start of media pick in	Processes the print job.
	the designated input tray until	●
	the last sheet is delivered to the	●	The page is picked from the designated tray and travels through
	designated output bin.		the media path to the print zone.
		●	As the page passes under the printhead, the printhead applies
			ink to the page.
		●	The page then enters the airflow assembly area where heated
			air might be applied to reduce the moisture content of the page.
		●	For Simplex print jobs, the page then proceeds to the output bin
			(face-down).
		●	For Duplex print jobs, the page then advances until the trailing
			edge of the media moves past the left side vertical path sensor.
			The page then reverses direction and proceeds down through
			the duplex path and underneath the left duplexer (service fluid
			container). Then the page turns upward, and re-enters the print
			zone.
			Ink is then applied to the second side of the page by the
			printhead.
		●	The process continues until all the pages of the print job are
			completed. The process might be interrupted by occasional
			printhead servicing events if the job includes many pages.

End of print job	Performed after the print job is	This period puts the printer in a state where it’s ready for the next
	completed, and continues until	print job.
	the next job is initiated.	●
		●	After a short dwell interval, the printhead will be allowed to cap.
		●	If needed, servicing or nozzle presence detection occurs, but
			these events are interruptible if another job is initiated.
		●	The printhead moves to the capping position.
		●	The printhead wiper moves to cap the printhead.

Standby	The printer is sitting idle, waiting	This period is intended to conserve energy while the printer is sitting
	for the next print job to be	idle. Certain functions might be disabled to save power, and then
	initiated.	restarted when needed. The printer has two standby modes:
		●	Idle mode—The printhead is capped and the printer is ready to
			immediately start a new job
		●	Sleep 1 mode—After the printer is inactive for about 10 minutes
			(a setting that can be adjusted from the control panel or the
			Embedded Web Server), the control panel turns o and the
			power LED blinks to indicate the unit is in Sleep mode. When in
			Sleep mode, the printer must wake up and go to idle mode
			before all printer functions are available. The printer is designed
			to wake up from Sleep mode based on certain interactions with
			the printer, such as touching the control panel or opening a
			paper tray.
		●	Sleep 2 mode-After the printer is inactive for a longer period of
			time (typically 2 hours), the engine controller powers down to
			minimize power consumptions. This setting can be adjusted
			from the control panel.

ENWW	Basic operation 5

System control

The system control coordinates all the other systems, according to commands from the MPCA.

Figure 1-2 System control

I/O	FormaƩer		Datapath
	I/O, PDL, UI Control		ASIC + memory		Pen I/F


				Pen	energy control
				Pen	energy control
				Pen	voltage sequencing	Printhead
		Power supply		Signal integrity		Printhead
		Power supply		Ink-short protecƟon		56,000 nozzles
				Ink-short protecƟon
				Ink pumps
				Printhead interconnects
			AC control

	Engine control			Ink supply
				Ink supply
			module
	Motor + sensor drive		module
	Motor + sensor drive		Airﬂow system
			Airﬂow system

●MPCA

●Data path

●Engine control

●Pen interface

●Power supply

●AC control module

MPCA digital ASIC

The MPCA digital ASIC contains dual ARM CPUs (one at 512 MB and one at 600MHz) that execute rmware code that provides high-level device control. The digital ASIC uses a standard PCle interface to pass data to the formatter ASIC.

MPCA analog ASIC

The MPCA ASIC generates the system voltage for the MPCA, formatter drives the scanner and ADF motors, manages the real-time clock, and drives the fax speaker.

Formatter and data path

IMPORTANT: Do not simultaneously install a replacement trusted platform module (TPM), hard disk drive (HDD MFP), eMMC (SFP) and formatter PCA. Remove and install each part separately, making sure to turn the printer power on between installations. Failure to do so results in an unusable printer.

The formatter controller ASIC controls the input/output (I/O) control, the user interface, and the rendering of page description language les into printer-speci c commands.

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Input/output (I/O) control

The printers support 10/100/1000 Ethernet, 802.11 wireless and NFC (some 765 and 780/785 models), a rear USB host port, a rear USB device port, a walk-up USB host port, and analog fax port (some 780/785 models).

The formatter PCA controls the USB device and USB host. The optional dual USB host port accessory is also connected to the formatter after user installation.

Wireless and NFC I/O are provided via a separate radio module.

User interface

The printers contain either a 4.3-in (765 models) or an 8-in (780/785 models) color graphics display. For wireless models, there is an icon on the control panel to denote that the wireless feature is enabled. The printers include a walk-up USB host port for connection to thumb drives.

Formatter digital ASIC

The formatter digital ASIC has dual ARM CPUs (1.2 GHz) that execute rmware code that provides high-level device control. The digital ASIC uses a standard PCle interface to pass data to the engine control ASIC. The formatter rmware is located on either a 320 GB hard-disk drive (HDD) on 780/785 models, or an embedded 8 GHz MultiMedia Card (eMMC) or optional HDD on 765 models.

Additionally, the formatter digital ASIC manages the real-time clock, interfaces to the mass storage controller ASIC, provides control of USB ports, and interfaces with the Ethernet LAN ASIC and fax module.

Formatter Ethernet ASIC

The formatter Ethernet ASIC connects to the formatter digital ASIC with a PCIe interface to transmit and receive network packets.

Formatter mass storage ASIC

The formatter mass storage ASIC bridges between the formatter digital ASIC (via PCIe interface) and the mass storage device (via SATA interface). The 780/785 models use a rotating media HDD, while the 765 models use eMMC an optional HDD is available.

Formatter memory

Formatter memory is installed on-board and there is support for additional DIMM memory installation. The size of the memory on the formatter is 1.5 GB for 765 models and 2.5-3.0 GB for 780/785 models. An optional 1GB DIMM is available as a customer accessory.

Real-time clock

The real-time clock (RTC) allows the fax module to time-stamp outgoing faxes. It also determines the elapsed time between printhead and ISS calibration events. The RTC uses a separate device connected to the formatter digital ASIC, along with a crystal and a battery.

Late point di erentiation con guration (LPDC)

Allows the channel partner to con gure the speed to the printer depending on the customer’s order. LPDC

con guration is stored on the Trusted Platform Module (TPM). There are three methods to program the speed to the printer.

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●Automatic

●O line

●Manual

Engine control

The engine controller digital ASIC receives high-level commands from the MPCA, and it then provides low-level control to the print mechanism. In particular, the engine controller digital ASIC and its rmware control motors, system sensors, and the printhead. The engine controller analog ASICs integrate motor drivers, voltage regulators, sensor interfaces, and supervisory circuits.

Engine controller digital ASIC

The engine controller digital ASIC has a high-performance 480 MHz ARM CPU and DSP co-processors that execute rmware code to provide low-level engine control. It also drives a FPGA which then creates the printhead 15 high-speed LVDS transmission signals. The signals are routed from the engine PCA to the printhead via two large FFC cables. The engine controller digital ASIC receives pre-rendered data from the MPCA digital ASIC over a standard PCle interface.

When a printer enters Sleep mode, many functions of the printer go into a low-power mode. If a print job is received while the printer is in Sleep mode, the printer will take a short period of time to "wake up". This can take up to 15 seconds, which will delay the rst page out (FPO) time accordingly.

Engine controller analog ASICs

The engine uses six analog ASICs to generate the system voltages for the engine, drive the engine motors, control various engine sensors, and monitor printhead power delivery for correct operation.

The engine contains 24 motors, 3 solenoids and 2 fans:

NOTE: The air flow fan is created using a DC motor.

Certain models might have fewer motors, depending upon the exact con guration of the paper trays.

Motors

●Tray 1 pick motor

●Tray 2 lift motor

●Tray 3 lift motor

●Tray 1 separation motor

●Tray 2 separation motor

●Tray 3 separation motor

●Duplex diverter motor

●Duplex entry motor

●Duplex exit motor

●Finisher diverter motor

●Vertical motor

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●Deskew motor (front)

●Deskew turn motor (back)

●Scanning carriage motor

●Stack control motor

●Printhead wiper motor

●Eject motor

●Drop detect carriage motor

●Print zone feed motor

●Ink pump motor

●Ink prime motor

●Air flow fan motor (for the air flow fan)

●Printhead lift motor

Solenoids

●Tray 2 pick solenoid (E-clutch)

●Tray 3 pick solenoid (E-clutch)

●Ink prime vent solenoid

Fans

● irflow fan

Aerosol fan

Most motors are DC motors with encoder feedback, to provide precision servo control. These motors are driven directly by one of the engine analog ASICs.

The printer uses many sensors to track the media as it travels through the paper path. Most of these are optical reflective edge detection interrupter (REDI) sensors, which are used in conjunction with mirrors to sense the presence or absence of paper in the paper path. These are carefully aligned and calibrated at the factory, so care must be taken when servicing these sensors. See the remove and Replace chapter of the Repair manual for more details.

Other printed circuit assemblies

In addition to hosting the system ASICs, the engine printed circuit assembly (PCA) incorporates many of the circuits required to interface with sensors and other sub-system components. In some cases, this circuitry is located on a smaller remote PCAs (SLBs) to optimize cable interconnects. The following table lists the various PCAs in the base mechanism engine/MPCA.

ENWW	System control 9

Name	Description/Function	Name	Description/Function

Left door PCA	Distribution	Main bin full sensor PCA	Main bin paper out sensor

Printhead lift encoder PCA	Printhead lift	Heat zone temperature	Air flow assembly temperature
		thermistor PCA	sense

Feed motor encoder PCA	Feed motor	Contact size detect PCA	Paper length/width detect

Left front upper PCA	Distribution	SIM PCA	SHAID and distribution

Air flow assembly PCA	Air flow assembly	TT dashboard PCA	Tabletop control panel interface

Center rear lower PCA	Distribution	HE1 PCA	Hall e ect sensor

Left rear lower PCA	Distribution	Button on/o PCA	Base mechanism on/o
			interface

AC control module PCA	AC control for air flow assembly	Power button interface PCA	Base mechanism on/o	button

Printhead registration sensor	Printhead sensor	eMMC module PCA (8 GB)	eMMC module
PCA

Main logic PCA	MPCA and engine	Power button PCA	Base mechanism on/o	button

Through beam optical drop	TBODD sensor	Light pipe PCA	Light pipe LED
detect (TBODD) PCA

Drop detect carriage PCA	TBODD carriage	Main bin LED PCA	Main bin LED

Opto OOP lift plate sensor PCA	Tandem tray sensor	Hall e ect left door PCA	Left door hall e ect

Separation PCA	Tandem tray distribution	Temperature/humidity	Multiple sensors
		sensor/NVM/HE PCA

Connector width adjust sensor	Multi-purpose tray sensor	Carriage drop detect motor PCA	Motor cable connect
PCA

Duplex spittoon contact PCA	Duplex spittoon contact	Flatbed scan interconnect PCA	Flatbed scan interface

Duplex spittoon EEPROM PCA	Duplex spittoon EEPROM	ADF PCA	ADF interface

Right rear lower PCA	Distribution	eMMC module PCA (16 GB)	eMMC module

Left rear upper PCA	Distribution	Acumen contact PCA	Acumen PCA

Pen interface (I/F)

The printhead is the key component that di erentiates this printer from other inkjet printers. The conventional approach is to print a page in horizontal swaths by moving a “scanning” printhead horizontally over a xed sheet of paper, advancing the paper a xed amount, and then printing the next swath. This printer moves the paper underneath a xed page-wide printhead in a single, smooth motion.

Single-pass page-wide printing requires that data and power be delivered to the printhead at a very high rate, while also maintaining good control of paper position as it moves past the printhead nozzles.

The engine printed circuit assembly (PCA) sends power and data to the printhead via two large flat flexible cables (80 pins for the data and 26 pins for the power). The printhead PCA routes power and data to 14 printhead die, which are attached to the printhead PCA using a flexible tab circuit and wire-bonding process.

The printers also contain electronics to control the ink supply station (ISS). The SIM PCA has several functions. It detects low-ink conditions by detecting presence of ink and/or ink foam in the X-chamber. The SIM PCA also collects and distributes electrical signals that drive the ink pump and prime motors, engage the solenoids, and

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read the ink supply acumen data. All data communications between the ISS and engine PCA are routed through a single 20-pin FFC.

Each ink supply has a memory tag that stores information about its type of ink, the amount of ink remaining, and other critical data. It uses a special authentication scheme to ensure that only genuine HP supplies are used and the printer is not damaged by using invalid supplies. Acumen uses a two-line serial bus which, along with 3.3 V and ground, is cabled via the SIM PCA to the engine PCA and the engine control digital ASIC.

Power supply

The power supply module converts 100-240 VAC to 34 VDC to power the system. The power supply module has a sleep mode that reduces power consumption in system low-power modes. When in its sleep mode, the power supply generates less than 20 W.

The power supply module supplies 34 V to the engine PCA. The power supply module has two operating modes, depending upon the state of its nSLEEP input pin:

●Printing = up to 170 W ( nSLEEP = high logic level)

●Sleep mode = < 20 W ( nSLEEP = low logic level)

The power supply is a self-contained module that can be replaced if it is defective (see the Remove and Replace chapter of the Repair manual).

To ensure safe operation, the power supply will “latch o ” if a persistent over-current fault condition exists. This would typically be caused by a short-circuit from 34 V to ground in the printer. Less severe faults can cause the power supply to latch o , if present for an extended period of time, or if the printer is operated above the recommended operating temperature range. In addition, the power supply output is split into 7 “rails”, each with separate output fusing as an additional safety feature.

NOTE: The power supply includes fusible links for the AC output from the power supply to the AC control module, and then to the airflow assembly.

AC control module

The AC control module performs the following functions related to the heating elements in the air flow assembly:

●Low-cost voltage monitor

a.The voltage of the outlet, which the printer is attached, is monitored to ensure the printer remains

operational, even in a low-quality-power environment. This is done by instantly shutting o heater power until the minimum voltage threshold is met. Hysteresis is included to avoid rapid fluctuations in voltage.

b.This circuit generates a frequency modulated signal that is sent across the isolation barrier, and

interpreted by rmware in the engine.

●Isolation

–Isolates the low voltage heater control signals from the high voltage AC power that is applied to the heater. This is a safety feature to ensure line transients (i.e. lightning) aren’t coupled into the low voltage system, which could cause damage to the printer or user.

●AC switch

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–	Switches AC power on/o to the heater using TRIACs.

●Heating Element Con guration

–Using relays, the heating element con guration is changed between series and parallel, in coordination with applied voltage. This is done to have a predictable temperature pro le that is functional across the full range of worldwide voltages (90-240VAC).

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