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HP 8550 Service Manual - Page 733

Q, R, I/O states 80

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pressure, separation belt adjusting 152 pre-transfer assembly troubleshooting 462 pre-transfer charging assembly faults 466 pre-troubleshooting checklist 457 print engine adjustments 120 printer disassembling 332 troubleshooting 457 printer drivers handled by HP Driver Distribution Center 44 obtaining 40 request form 43 troubleshooting 457 printer formatter 304 printer power cord connector diagrams 26 printer/HCI gap, adjusting 159 priorities, setting 53 priority on image quality mode 204 priority on speed mode 204 product data sheets 43 PS/PCL board, troubleshooting 508 pulley cover, removing 442 pulley kits, part numbers automatic document feeder (ADF) 601 high-capacity input (HCI) 649 pullouts 331 Q quality auto gradation adjustments 125 background cancellation 213 end user adjustments 121 image priority mode 204 image, options 99 image, troubleshooting 476 R R image signal 210 rail, scanner cleaning 525 lubricating 174 rate of saving, power 53 ratios, reproduction automatic selection 197 horizontal 222 theory of operations 192 vertical 222 ratios, RGB 84 R-CON menu 80 RDF controller, diagrams and part numbers 644 read address 227 EN reader controller PCB circuitry 179, 180 communication control 232 diagrams 587 I/O states 80 original size, identifying 199 part numbers 587 pass-through only 200 resetting 62 scanner motor 192 scanning lamp control 193 troubleshooting 509 READY indication 93 rear cover (copy module) identifying 333 removing 336 rear cover (HCI) identifying 434 removing 436 rear power switch diagrams 26 using 177 recalibrating CCD 128 exposure 56 exposure adjustments 126 lamp output 127 re-circulating lever idle rotation 281 recirculating lever operations 274 recirculation lever idle rotation 74, 283 recirculation sensor (S14) 279, 282 reduced page composition original sizes 255 sequence of operations 263, 265 reduction automatic 51 specifications 23 theory of operations 192, 222 reentering settings 62 reflecting faces, cleaning 170 reflector, part numbers 698 registration paper sensor adjusting 155 cleaning 170, 172 detecting original direction 271 functions 279, 282 settings 79 registration roller diagrams 31 faults 470 removing 402 sequence of operations 258 troubleshooting 482, 544 Index 731

Section	Page
Contents	5
Figures	7
Tables	19
Product information	23
Introduction	25
Copy module	25
Features	25
Specifications	26
Overview	28
Automatic document feeder (ADF)	30
Features	30
Specifications	31
Overview	32
Side high-capacity input (side HCI)	34
Features	34
Specifications	34
Overview	35
Model and serial numbers	37
Safety and regulatory information	37
Declaration of conformity	37
FCC regulations	38
Service approach	39
Service approach overview	41
Parts and supplies	41
Ordering	42
Obtaining related documentation and software	42
Ordering consumables	43
Ordering FRUs	43
Parts exchange program	43
Technical assistance	44
List Server	44
HP ASAP	44
HP FIRST	45
Dealer Response Line	46
HP Software Distribution Center	46
HP Direct	46
Customer Support Sales Center	46
Parts identification	46
Customer Information Centers	46
HP Customer Care Centers (CCC)	47
Warranty	48
Operational overview	49
Control panel	51
Copy module functionality	53
User mode	54
Automatic gradation adjustment	59
Cold reset	59
Original-set indicator (ADF)	60
Warnings and actions	60
Self-diagnostic messages	61
Service mode	62
Overview	62
Navigating service mode screens	65
Copier, display mode (DISPLAY)	67
Copier, I/O mode (I/O)	79
Copier, adjust mode (ADJUST)	85
Copier, run/check mode (FUNCTION)	95
Copier, machine settings (OPTION) mode	100
Copier, test print mode (TEST)	110
Copier, counter mode	113
Feeder	116
Adjustments and maintenance	119
Overview	121
MFP print engine adjustments	121
Parts unique to the HP LaserJet 8550MFP print engine	121
Adjustments unique to the HP LaserJet 8550MFP print engine	122
Copy module adjustments	123
End-user adjustments	123
Mechanical and electrical adjustments	124
Required adjustments when replacing parts or upgrading	131
Upgrading and localizing the copy module firmware	137
ADF adjustments	142
Mechanical adjustments	143
Electrical adjustments	157
Replacing the DADF controller PCB	160
Side HCI adjustments	161
Gap between the printer and the side HCI	161
Base plate position	162
Paper-size change (A4 or letter)	163
Periodically replaced parts	165
Cleaning	166
Cleaning by an end-user	166
Cleaning by service technicians	166
Solvents	166
Cleaning parts on the copy module	167
Cleaning ADF parts	169
Cleaning side HCI parts	175
Lubricating	176
Theory of operation	177
Introduction	179
Notes on the power switch	179
Copy module	180
Functional construction	180
Outline of electrical circuitry	181
Inputs to and outputs from the major PCBs	182
Basic sequence of operations	185
Sequence of operations during copying	187
Copy module exposure system	190
Scanner home position sensor and operation	192
Scanner motor	193
Controlling the scanning lamp	195
Identifying the size of originals when copying from the glass	199
Copy module image processing system	202
CCD	203
CCD driver	204
AP-IP (analog image processing) PCB	205
Digital image processing	208
Control panel	234
Fan	236
Power supply	237
ADF	246
ADF electrical circuitry	246
Communication with the copy module	247
Inputs and outputs to the DADF controller PCB	248
Basic operation	251
Functional overview	252
Picking up originals	258
Reversal operation	263
Reduced page composition	265
Delivery operation	268
Detecting originals	271
Controlling the pick-up motor	277
Controlling the belt motor	279
Detecting jams	281
Improper placement of originals	284
Power supply	287
Motors, solenoids, and sensors	288
PCBs	289
Indicator PCB	290
General timing charts	290
Side HCI	306
Pick-up feed system	309
Power supply	316
Sensors	317
Solenoids and motors	318
PCBs	319
List of variable resistors (VR), LEDs, check pins by PCB	320
Input and output signals to the deck controller PCB	323
General circuit diagram	326
Removal and replacement	329
Required tools	333
Repair notices	334
Copy module	335
Identifying the external covers	335
Removing the lower front cover	336
Removing the upper right cover	336
Removing the upper rear cover	337
Removing the upper left cover	337
Removing the rear cover	338
Removing the upper front cover	339
Removing the scanner motor	340
Removing the scanner motor driver PCB	341
Removing DIMMs on the reader controller PCB	342
Removing the control panel	346
Removing the LCD assembly	348
Removing the flexible cable	355
Removing the scanning lamp and scanning lamp heater	359
Removing the standard white plate cover	365
Removing the intensity-detection PCB	366
Removing the lens-mount cover and CCD unit	367
Removing the electrical unit pullout	369
Removing the reader controller PCB	372
Removing the ECO-2 PCB	373
Removing the AP-IP PCB	374
Removing the copy module main power supply PCB (DCP1)	375
Removing the accessories power supply PCB (DCP2)	376
Removing the power supply cooling fan (FM4)	377
Removing the inverter PCB unit	378
Automatic document feeder (ADF)	379
Identifying external covers	379
Removing the ADF	380
Removing the body cover	382
Mounting the original-width detecting volume	385
Removing the pick-up motor unit	387
Removing the ADF motor unit	389
Removing the belt motor	391
Removing the clutch unit	394
Removing the delivery motor	396
Removing the pick-up roller	398
Removing the separation belt unit	400
Removing the feeding roller unit	401
Removing the registration roller	404
Removing the delivery/reversing roller	409
Removing the delivery roller unit (bottom pick-up mode)	416
Removing the delivery roller unit (top pick-up mode)	418
Removing the reversing guide	421
Removing the stopper plate solenoid	424
Positioning the paper-retaining plate solenoid (SL2)	426
Positioning the paper-deflecting solenoid (SL3)	428
Removing the stamp solenoid	429
Removing the feeding belt	433
Side HCI	436
Identifying the external covers	436
Removing the upper left cover	437
Removing the front cover	437
Removing the rear cover	438
Removing the upper right cover	438
Removing the pick-up unit	439
Removing the pick-up roller	442
Removing the feed roller and separation roller	443
Removing the lifter wire	444
Removing the lifter motor (M1)	454
Removing the feeder motor (M2)	454
Removing the pick-up motor (M3)	455
Removing the deck controller PCB	455
Removing the power supply PCB	456
Troubleshooting	457
System-to-device troubleshooting	459
Pre-troubleshooting checklist	459
Process of elimination	460
Copy module troubleshooting	462
Overview	462
Necessary adjustments for replaced parts	462
Image fault troubleshooting	464
Image faults	478
Numbered error codes	495
Faults not identified by error codes	521
Using the copy module service mode to test parts	528
ADF troubleshooting	530
Fault isolation	530
Numbered error codes	531
Self-diagnosis	535
Check the output of the DADF controller PCB	536
Side HCI troubleshooting	537
Overview	537
User and service LEDs	538
Sensor and switch tests	540
Test pick-up	541
Faults not identified by error codes	543
Parts and diagrams	549
How to use this chapter	553
Printer parts unique to the HPColor LaserJet 8550MFP	554
Stand	557
Screw/ring kit	557
Stand assembly	558
Copy module	560
Screw/ring kit	560
Belt kit	561
Gear/pulley kit	562
Spring kit	562
Assembly location diagram	563
External covers and panels	564
Internal components	566
Power cord terminal assembly	572
Control panel assembly	574
Copyboard cover assembly	576
Mirror assembly 1	578
Electrical tray assembly	580
Dc power supply PCA	582
APC power supply PCA	584
Noise filter PCA	585
Control panel PCA	586
Control panel CPU PCA	587
Control panel inverter PCA	588
Reader controller PCA	589
Analog image processor PCA	590
Motor driver PCA	591
Inverter PCA	592
Connectors	593
ADF	602
Belt kit	602
Bushing kit	603
Gear/pulley kit	603
Pin kit	604
Screw/ring kit	604
Spring kit	606
Assembly locations	607
Mounting hardware	608
External covers and panels	609
DF assembly	610
Document tray assembly	614
Upper cover assembly	616
RF assembly	618
Right paper delivery assembly	632
Paper feed motor assembly	634
Belt drive motor assembly	636
Upper paper guide assembly	638
Lower paper guide assembly	640
Separation roller assembly	642
Paper separation assembly	644
RDF controller PCA	646
Connectors	647
Side HCI	651
Bushing kit	651
Gear/pulley kit	651
Screw/ring kit	652
Spring kit	653
Assembly locations	654
Mounting hardware	655
External covers and panels	656
Internal components	658
Lifter drive assembly	665
Paper pick-up assembly	666
Deck controller PCA	670
Connectors	671
Numerical parts list	674
Alphabetical parts list	682
Index	713
A	713
B	715
C	716
D	720
E	722
F	722
G	724
H	724
I	725
J	726
K	726
L	726
M	728
N	729
O	729
P	730
Q	733
R	733
S	735
T	739
U	740
V	740
W	740
X	741
Y	741

Match case Limit results 1 per page

Index

731

pressure, separation belt

adjusting 152

pre-transfer assembly

troubleshooting 462

pre-transfer charging assembly

faults 466

pre-troubleshooting checklist 457

print engine

adjustments 120

printer

disassembling 332

troubleshooting 457

printer drivers

handled by HP Driver Distribution Center 44

obtaining 40

request form 43

troubleshooting 457

printer formatter 304

printer power cord connector

diagrams 26

printer/HCI gap, adjusting 159

priorities, setting 53

priority on image quality mode 204

priority on speed mode 204

product data sheets 43

PS/PCL board, troubleshooting 508

pulley cover, removing 442

pulley kits, part numbers

automatic document feeder (ADF) 601

high-capacity input (HCI) 649

pullouts 331

quality

auto gradation adjustments 125

background cancellation 213

end user adjustments 121

image priority mode 204

image, options 99

image, troubleshooting 476

R image signal 210

rail, scanner

cleaning 525

lubricating 174

rate of saving, power 53

ratios, reproduction

automatic selection 197

horizontal 222

theory of operations 192

vertical 222

ratios, RGB 84

R-CON menu 80

RDF controller, diagrams and part numbers 644

read address 227

reader controller PCB

circuitry 179, 180

communication control 232

diagrams 587

I/O states 80

original size, identifying 199

part numbers 587

pass-through only 200

resetting 62

scanner motor 192

scanning lamp control 193

troubleshooting 509

READY indication 93

rear cover (copy module)

identifying 333

removing 336

rear cover (HCI)

identifying 434

removing 436

rear power switch

diagrams 26

using 177

recalibrating

CCD 128

exposure 56

exposure adjustments 126

lamp output 127

re-circulating lever

idle rotation 281

recirculating lever

operations 274

recirculation lever

idle rotation 74, 283

recirculation sensor (S14) 279, 282

reduced page composition

original sizes 255

sequence of operations 263, 265

reduction

automatic 51

specifications 23

theory of operations 192, 222

reentering settings 62

reflecting faces, cleaning 170

reflector, part numbers 698

registration paper sensor

adjusting 155

cleaning 170, 172

detecting original direction 271

functions 279, 282

settings 79

registration roller

diagrams 31

faults 470

removing 402

sequence of operations 258

troubleshooting 482, 544