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Xerox 4400DT Service Manual - Page 440

Fuser Trouble (U4 Error Code), AC Power Shutoff to the Fuser, Fuser Temperature Cycling

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Fuser Trouble (U4 Error Code) There are five major causes of a U4 error. I Warm-up failure - Fuser warm-up does not complete within specified seconds after starting. I Low Trouble temperature - The Fuser temperature drops to the Low Trouble temperature (approximately current control temperature, minus approximately 25° C. I High Trouble temperature - The Fuser temperature rises to the High Trouble temperature (approximately current control temperature, plus approximately 35° C. I Thermistor circuit opened. I STS failure - The Heat Rod remains on for at least ten seconds after warm-up has completed. AC Power Shutoff to the Fuser There are eight reasons that the printer shuts off AC power to the Fuser. I Fuser Failure (U4) I Paper jam I Open Front/Rear Cover Assembly I Laser failure (U2) I CPU or NVRAM problem (U6) I Main Motor Assembly problem (U1) I Fan problem (U5) I FUSER PAUSE command issued Fuser Temperature Cycling Fuser Temperature Cycling Temperature Name Temperature Value High Trouble Temperature Approximately 215° C (Standby temperature + approximately 35° C) Fuser Off Temperature Fuser control temperature +/- 0 ° C Fuser Control Temperature Standby temperature (180° C) Running temperature (195° C) Fuser On Temperature Fuser control temperature - 2° C Low Trouble Temperature Approximately 155° C (Standby temperature - approximately 25° C) Phaser 4400 Laser Printer Service Manual 8-27

Section	Page
Front Cover	1
Title Page	3
Copyright	4
Power Safety Precautions	6
Electrostatic Discharge (ESD) Precautions	7
Service Safety Summary	8
Servicing Electrical Components	9
Regulatory Specifications	10
Safety Standards	12
Contents	14
General Information	18
Section Contents	18
Phaser 4400 Laser Printer Overview	19
Configurations	19
Printer Memory Configuration	20
Monitoring Consumables	20
Repackaging Information	20
Parts of the Printer	21
Base Configuration Components	21
Internal Components	23
Printer Options	23
Front Panel Configuration	25
Image Processor Board	27
Machine Orientation	29
Menu Map	30
Printer Specifications	31
Physical Specifications	31
Media and Tray Specifications	31
Functional Specifications	35
Electrical Specifications	36
Environmental Specifications	36
Error Messages and Codes	38
Section Contents	38
Introduction	38
Service Flowchart	39
Service Technician Cautionary Statements	40
Procedures	40
Voltage Measurements	41
Using Fault History	42
Service Diagnostics	44
Entering Service Diagnostics	44
Service Diagnostics Menu Map	45
Using the Front Panel with Service Diagnostics	46
Engine Test Print	47
Engine NVRAM Default Settings	47
Printer Error Messages	48
Index of Errors	48
Error Message Summaries	49
Jam at Tray [#]. Open Tray [#] and Front Cover.	55
Jam at Envelope Feeder; Remove Feeder and Open Front Cover.	58
Jam at MPT; Open Front Cover to Clear.	59
Jam at Front; Open Front Cover to Clear.	60
Jam At Exit; Open Rear Cover To Clear.	62
Jam at Stacker; Open Both Rear Covers to Clear.	64
Jam at Front/Rear; Open Front/Rear Cover to Clear.	66
Paper Size Jam; Check Size and Open Rear Cover to Clear. (PSE-1)	67
Close Front Cover/Close Rear Cover.	68
Install or Reseat Print Cartridge.	70
Replace Print Cartridge.	71
Toner is Low.	72
Maintenance Kit is Near End of Life.	73
Install or Reseat the Duplex Unit.	73
Stacker Failure.	74
Install or Reseat the Envelope Feeder.	74
Standard Output Tray is Full. Unload Paper.	75
Tray [#] Paper is Low.	76
Tray 2 (or Tray 3) Paper is Low.	77
No Paper in Tray [#].	78
Load Tray [#] with [paper size] [paper type].	79
Tray [#] Failure. Open and Close Tray [#].	80
Main Motor Failure.	82
Laser Unit Failure.	85
Fuser Failure.	86
Fan Failure; Power Off Now.	86
Engine Logic Board NVRAM Failure.	87
Load MPT with [paper size] [paper type].	88
Tray 2 or 3 Failure.	89
Stacker is Full, Unload Paper.	91
Load Envelope Feeder with [paper size] [paper type].	92
Install or Reseat Print Cartridge.	94
Image Processor POST Error Codes	95
Fault Reporting Devices	95
15: RAM DIMM (RAM Error)	97
Troubleshooting	98
Section Contents	98
Introduction	98
Measurements	98
Troubleshooting Procedures	99
Index of Troubleshooting Procedures	99
Verifying AC Power	99
DC Power (LVPS)	101
DC Power Loading	103
Toner Sensor Failure	105
Inoperative Printer	106
Malfunctioning Front Panel	108
Inoperative Front Panel	110
Erratic Printer Operation	110
Power Supply	111
Main Motor Assembly	112
Laser Assembly	114
Fuser Assembly	115
Registration Sensor	117
MPT No Paper Sensor	118
Tray 1 No Paper Sensor	119
Output Tray Full Sensor	119
Stack Height Sensor Checkout	120
Print Cartridge Sensor Assembly	121
Tray Motor Assembly Checkout	123
Registration Clutch	124
Turn Roller Clutch Assembly	125
Tray 1 Feed Clutch	126
MPT Pick Up Solenoid	127
Image Processor Isolation	128
High-Voltage Power Supply (HVPS) Assembly	128
Electrical Noise	130
Exit Sensor	131
Exit Motor	132
550-Sheet Feeder Feed Clutch	133
Stacker Full Sensor	134
Stacker Offset Operation Not Performed	135
Envelope Feed Clutch	135
Envelope No Paper Sensor	136
Image-Quality Checkout Procedures	138
Index of Image-Quality Checkout Procedures	138
Image-Quality Defect Definitions	138
Deletions (Line, Band, Spots)	141
Fusing	142
Resolution	143
Registration (Side-to-Side)	144
Registration (Lead Edge-to-Trail Edge)	145
Skew	146
Skips / Smears	147
Spots	148
Other Print Defects	149
Image-Quality Troubleshooting Procedures	150
Index of Image-Quality Troubleshooting Procedures	150
Light (Undertoned) Prints	151
Blank Prints	153
Black Prints	155
Vertical Deletions	156
Horizontal Deletions	158
Vertical Streaks	160
Horizontal Streaks	162
Spots	165
Unfused Image	166
Damaged Print	168
Resolution	169
Spot Deletions	170
Repeating Defects	171
Residual Image	172
Background	173
Uneven Density	175
Skewed Image	176
Registration	178
Skips / Smears	180
Tests Prints, Adjustments, and NVRAM Reset	182
Section Contents	182
Service Test Prints	182
Test Print	183
Engine Test Print	185
Adjustments	186
Registration	186
Fuser Temperature	187
Resetting NVRAM	188
Customer Menu Resets	188
Service Diagnostics Resets	189
Front Panel Shortcut Reset	189
Print Engine NVRAM	190
Cleaning and Maintenance	192
Service Preventive Maintenance Procedure	192
Recommended Tools	192
Cleaning	192
FRU Disassembly	194
List of Procedures	194
Covers and Trays	199
RRP 1.1 Left Interface Cover	199
RRP 1.2 Left Cover	200
RRP 1.3 Option Cover	201
RRP 1.4 Top Cover Assembly	202
RRP 1.5 Right Cover	203
RRP 1.6 Front Cover Assembly	204
RRP 1.7 Left Front Cover	205
RRP 1.8 Rear Cover Assembly	206
RRP 1.9 Front Panel Assembly	207
RRP 1.10 Interlock Cover	208
RRP 1.11 Left Plate	209
RRP 1.12 Plate Handle	210
Tray 1	211
RRP 2.1 Retard Roller Assembly	211
RRP 2.2 Friction Clutch Assembly	213
RRP 2.3 Retard Spring	215
RRP 2.4 Motor Assembly	217
RRP 2.5 Paper Feeder Connector and Socket Guide	219
Paper Feed (Tray 1)	221
RRP 3.1 Paper Feeder	221
RRP 3.2 Turn Roller Assembly	222
RRP 3.3 Tray 1 No Paper Actuator	223
RRP 3.4 Stack Height Sensor	224
RRP 3.5 Low Paper Sensor	225
RRP 3.6 Feed Clutch Assembly	226
RRP 3.7 Feeder Assembly	228
RRP 3.8 Paper Feed Rollers	229
RRP 3.9 Feeder PWB	230
RRP 3.10 Feeder Socket	232
RRP 3.11 Size Sensor Housing	233
RRP 3.12 Size Sensor Actuators	234
RRP 3.13 Tray 1 Size PWB	235
RRP 3.14 Size Harness Assembly	236
Paper Feed (MPT)	237
RRP 4.1 MPT Chute Assembly	237
RRP 4.2 MPT Feed Roller Assembly	238
RRP 4.3 MPT Feed Roller	240
RRP 4.4 Bottom Tray Assembly	241
RRP 4.5 MPT No Paper Actuator	243
RRP 4.6 Tray Pick Up	244
RRP 4.7 Retard Pad Assembly	245
RRP 4.8 MPT No Paper Sensor	246
RRP 4.9 MPT Pick Up Solenoid	248
RRP 4.10 Envelope Connector Assembly	249
Paper Transportation	250
RRP 5.1 Paper Handler Assembly	250
RRP 5.2 Toner Sensor	252
RRP 5.3 Registration Actuator	253
RRP 5.4 Registration Sensor	254
RRP 5.5 Registration Clutch	255
RRP 5.6 Rubber Registration Roller	255
Exit Assembly and Fuser	258
RRP 6.1 Transport Chute Assembly	258
RRP 6.2 Fuser Assembly	259
RRP 6.3 Fuser Harness Assembly	260
RRP 6.4 Exit Chute Assembly	262
RRP 6.5 Exit Motor Assembly	264
RRP 6.6 Output Tray Full Sensor	265
RRP 6.7 Mid 1 and Mid 2 Roller Assemblies	266
RRP 6.8 Output Tray Full Actuator	269
RRP 6.9 Fuser Upper Cover Assembly/ Heat Rod	270
Xerographics	272
RRP 7.1 Transfer Roller Assembly	272
RRP 7.2 Print Cartridge Top Guide Assembly	273
RRP 7.3 Print Cartridge Sensor Assembly	274
RRP 7.4 Laser Assembly	275
RRP 7.5 Print Cartridge Side Guide	276
Main Drive	277
RRP 8.1 Main Motor Assembly	277
RRP 8.2 Main Drive Gear Assembly	278
Electrical	280
RRP 9.1 Fan Assembly	280
RRP 9.2 Image Processor Board	281
RRP 9.3 Engine Logic Board	282
RRP 9.4 5 VDC PWB	283
RRP 9.5 LVPS PWB	284
RRP 9.6 HVPS PWB	285
RRP 9.7 Connector PWB	287
RRP 9.8 Main Switch	288
RRP 9.9 Front Interlock Switch Assembly	289
RRP 9.10 Rear Interlock Switch Assembly	290
RRP 9.11 Stacker Harness Assembly	291
RRP 9.12 Duplex Harness Assembly	292
Stacker	294
RRP 10.1 Stacker	294
RRP 10.2 Exit Tray Extension	295
RRP 10.3 Exit Tray	295
RRP 10.4 Rear Cover Assembly	297
RRP 10.5 Lower Cover	298
RRP 10.6 Inner Exit Chute Assembly	299
RRP 10.7 Stacker PWB	300
RRP 10.8 Motor Drive Assembly	301
RRP 10.9 Static Eliminator	302
RRP 10.10 Direction Solenoid	303
RRP 10.11 Exit Sensor Assembly	304
RRP 10.12 Stacker Full Sensor Actuator	305
RRP 10.13 Stacker Full Sensor	306
RRP 10.14 Offset Roller Assembly	307
RRP 10.15 Mid Roller Assembly	308
RRP 10.16 Offset Assembly	310
RRP 10.17 Offset Motor Assembly	311
RRP 10.18 Offset Assembly Home Sensor	312
Optional Paper Feeder	313
RRP 11.1 Printer Removal	313
RRP 11.2 550-Sheet Feeder Right Cover	314
RRP 11.3 550-Sheet Feeder Left Cover	315
RRP 11.4 550-Sheet Feeder Gear Bracket Assembly	316
RRP 11.5 Top Plate	317
RRP 11.6 550-Sheet Feeder Drive Assembly	318
RRP 11.7 No Paper Actuator	319
RRP 11.8 Turn Roller Assembly	320
RRP 11.9 Feeder PWB	321
RRP 11.10 Feed Clutch Assembly	322
RRP 11.11 Paper Feed Rolls	323
RRP 11.12 Feeder Assembly	324
RRP 11.13 Stack Height Sensor	325
RRP 11.14 Low Paper Sensor	326
RRP 11.15 Feeder Socket	327
RRP 11.16 550-Sheet Feeder Size Harness Assembly	328
RRP 11.17 Size Sensor Housing Assembly	329
RRP 11.18 Size Sensor Actuators	331
RRP 11.19 Size PWB	332
RRP 11.20 Size Harness Assembly	333
Duplex Unit	334
RRP 12.1 Duplex Unit	334
RRP 12.2 Turn Chute Assembly	335
RRP 12.3 Duplex Cover	336
RRP 12.4 Duplex PWB	337
RRP 12.5 Drive Cover	338
RRP 12.6 Connector Chute Assembly	339
RRP 12.7 Upper Chute Assembly	340
RRP 12.8 Motor Assembly	342
RRP 12.9 Rear Roller Assembly	343
RRP 12.10 Middle Roller Assembly	344
RRP 12.11 Front Roller Assembly	346
RRP 12.12 Synchronous Belt	347
RRP 12.13 Duplex Sensor	348
RRP 12.14 Duplex Unit Home Sensor	349
Envelope Feeder	350
RRP 13.1 Bottom Cover	350
RRP 13.2 Top Chute	351
RRP 13.3 Envelope Feeder PWB	352
RRP 13.4 Retard Roller Assembly	353
RRP 13.5 Exit Pinch Roller	354
RRP 13.6 Exit Sensor Assembly	355
RRP 13.7 Weight Arm	356
RRP 13.8 Tray Extension	357
RRP 13.9 No Paper Actuator	358
RRP 13.10 No Paper Sensor	359
RRP 13.11 Gear Cover	360
RRP 13.12 Feed Clutch	361
RRP 13.13 Transport Roller Assembly	362
RRP 13.14 Bottom Roller Assembly	363
RRP 13.15 Feed Roller Assembly 1	365
RRP 13.16 Feed Roller Assembly 2	367
RRP 13.17 Feed Belts	369
Parts Lists	372
Parts List Index	372
Using the Parts Lists	372
Covers (1 of 2)	373
Covers (2 of 2)	375
Paper Tray 1	377
Paper Feeder	381
MPT Chute	383
Paper Transport	385
Chute Transport and Fuser	387
Exit	389
Drive and Xerographics	391
Frame and Size Sensor	393
Electrical	395
Optional Feeder 1	397
Optional Feeder 2	399
Envelope Feeder 1	401
Envelope Feeder 2	403
Duplex 1	405
Duplex 2	407
Stacker 1	409
Stacker 2	411
Theory of Operation	414
Section Contents	414
Print Process Overview	416
Print Process Description	418
Charge	418
Exposure	419
Development	419
Transfer	421
Discharge	422
Cleaning	423
The Paper Path	424
The Three Possible Paper Paths	425
Drive Flow	427
Drive Transmission to the MPT Roller Assembly	428
Drive Transmission to the Turn Roller Assembly	429
Drive Transmission to the Feeder Assembly	430
Drive Transmission to the Rubber Registration Roller Assembly	431
Drive Transmission to the Drum and the Transfer Roller	432
Drive Transmission to the Fuser Assembly	433
Drive Transmission to the Exit Components	434
Engine Logic Board and Front Panel Functions	435
Image Processor Board	435
5 VDC PWB	435
Power Supplies	436
The Low Voltage Power Supply (LVPS)	436
The High Voltage Power Supply (HVPS)	436
Interlocks	437
Laser Control	438
Laser Self-Check	438
Printable Area	438
Laser Trouble (U2 Error Code)	439
Fuser Control	439
Fuser Temperature Control	439
Fuser Temperature Adjustment	439
Fuser Warm-up	439
Fuser Trouble (U4 Error Code)	440
AC Power Shutoff to the Fuser	440
Fuser Temperature Cycling	440
Erase Cycle	441
Fan Control	441
Duplex Printing	442
Duplex Printing Paper Path	442
Duplex Printing Methods	444
Drive Flow	444
Function of Major Components	445
Envelope Feeder	446
Envelope Feeder Paper Path	446
Drive Flow	448
Function of Major Components	449
Stacker	450
Stacker Paper Path	450
Drive Flow	452
Function of Major Components	453
Stacker Control	453
Option Feeder Assembly	455
Option Feeder Assembly Paper Path	455
Drive Flow	457
Function of Major Components	458
Wiring Data	460
Section Contents	460
Introduction	461
Location of P/J Connectors	461
Wiring Diagram Notations	462
Base Engine Wiring Data	463
Base Engine P/J Table	463
Base Engine P/J Maps	465
Base Engine Block Diagrams	467
Wiring Diagrams	472
550-Sheet Feeder	481
550-Sheet Feeder P/J Table	481
550-Sheet Feeder P/J Map	482
550-Sheet Feeder Block Diagram 1 of 2	483
550-Sheet Feeder Block Diagram 2 of 2	484
Duplex Unit	485
Duplex Unit P/J Table	485
Duplex Unit P/J Map	486
Duplex Unit Block Diagram	487
Stacker	490
Stacker P/J Table	490
Stacker P/J Map	491
Stacker Block Diagram	492
Envelope Feeder	496
Envelope Feeder P/J Table	496
Envelope Feeder P/J Map	497
Envelope Feeder Block Diagram	498
Envelope Feeder Wiring Diagrams	499