Oki C7400n User manual

41316401TH Rev.4A 1 / 186
C7000 Series
Color LED Page Printer
SERVICE MANUAL
OkiData
01-23-2001 based on Rev.4

41316401TH Rev.4 2 /
1 2000-05-29 ISSUE E4 Yamazaki
2 2000-05-31 E4 Murakami
3 2000-12-04 NIP9 Yamazaki
4 2000-12-15 NIP9 Yamazaki
Rev.No. Date No.
Corrected items
Page Description of change Person in
charge
Document Revision History

41316401TH Rev.4 3 /
PREFACE
This manual describes the procedures forthe maintenance of the C7000 Series of printers.
Thedocumentisproducedformaintenancepersonneluse. Fordetailsontheproceduresforhandlingthe
C7000 Series of printers, see its user documentation.
Note! • The descriptions in this manual are subject to change without prior notice.
• Inpreparingthedocument,effortshavebeenmadetoensurethattheinformationinitisaccurate.
However, there may be errors in the document. Oki Data assumes no responsibility for any
damage resulting from, or claimed to be the results of, those repairs, adjustments or modifica-
tions to the printers which are made by users using the manual.
•The parts used for the printers are electrostatic sensitive and, if handled improperly, may be damaged.
It is strongly recommended that the products be maintained by Oki Data Authorized Repair Centers
Oki Data. .

41316401TH Rev.4 4 /
CONTENTS
1. CONFIGURATIONS ......................................................................................... 7
1.1 System Configuration....................................................................................................... 7
1.2 Printer Configuration ........................................................................................................8
1.3 Option Configuration ........................................................................................................ 9
1.4 Specifications................................................................................................................. 10
2. OPERATION DESCRIPTION ......................................................................... 12
2.1 Main Board (CRM PWB)................................................................................................ 13
13
2.2 Engine Controller Board (K71 PWB).............................................................................. 15
2.3 Power Units.................................................................................................................... 16
2.4 Mechanical Processes .................................................................................................. 17
2.4.1 Electrophotographic process............................................................................ 18
2.4.2 Paper running process ..................................................................................... 23
2.5 Sensor............................................................................................................................ 31
2.5.1 Paper related sensors ...................................................................................... 31
2.5.2 Other sensors................................................................................................... 32
2.6 Color Misalignment Correction....................................................................................... 33
2.7 Transfer Control Responds to Environmental Changes
(Room Temperatures and Relative Humidities)............................................................. 33
2.8 Paper Jam Detection ..................................................................................................... 34
2.9 Cover-Open ...................................................................................................................35
2.10 Toner Low Detection...................................................................................................... 36
2.11 Page Size Detection ...................................................................................................... 37
2.12 Operation at Power-on................................................................................................... 38
2.12.1 Self-diagnostic test ........................................................................................... 38
2.13 Color Misalignment Detection ........................................................................................ 39
2.14 Version Read of Units Replaced Periodically ................................................................ 40
2.15 Life Count for Units Replaced Periodically..................................................................... 40
2.16 Toner Consumption Detection ...................................................................................... 40
3. PARTS REPLACEMENT................................................................................ 41
3.1 Precautions in Replacing Parts...................................................................................... 41
3.2 Parts layout .................................................................................................................... 43
3.3 Replacing Parts..............................................................................................................49
3.3.1 Top Cover......................................................................................................... 51
3.3.2 LED Assy/ LED Assy Spring............................................................................. 52
3.3.3 Top Cover Unit ................................................................................................. 53
3.3.4 Control Panel Assy/ Control Panel Bezel/ LED Control PWB/ Toner Sensors/
Stacker Full Sensor/ Control Panel/ Control Panel Tape Harness/ Eject Rollers. 54
3.3.5 Top Cover Handle/ Top Cover Latch/ Top Cover Latch Spring........................ 55
3.3.6 Eject Guide Assy .............................................................................................. 56
3.3.7 Cassette Assy/ Front Cover Assy/ Front Cover Inner Baffle ........................... 57
3.3.8 Retard Pad Assy/ Retard Pad Assy Spring ...................................................... 58
3.3.9 Feed Roller and Nudger Roller......................................................................... 59
3.3.10 Rear Cover ....................................................................................................... 60
3.3.11 Face-Up Tray.................................................................................................... 61
3.3.12 Left Side Cover................................................................................................. 62
3.3.13 Right Side Cover .............................................................................................. 63
3.3.14 Multipurpose Tray Assy/ Multipurpose Tray Cover Assy/ Links/
Multipurpose Tray Top Cover/ Multipurpose Tray Drive Gear.......................... 64
3.3.15 Drum Contact Assys .......................................................................................... 65
3.3.16 Registration Roller Assy (A)/ Registration Drive Gear (A) ................................ 66
3.3.17 Registration Roller Assy (B) ............................................................................. 67
3.3.18 Registration Clutch and Registration Motor Assy............................................. 68
3.3.19 Main Cooling Fan ............................................................................................. 69

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3.3.20 Color Registration Sensor Assy........................................................................ 70
3.3.21 Duplex Guide Assy........................................................................................... 71
3.3.22 Electrical Chassis Cooling Fan......................................................................... 72
3.3.23 Printer Engine Controller PWB......................................................................... 73
3.3.24 Printer Unit Chassis.......................................................................................... 74
3.3.25 Entrance Cassette Sensor Actuator ................................................................. 75
3.3.26 Entrance Sensor PWB...................................................................................... 76
3.3.27 Entrance MT Sensor Actuator and Entrance Belt Sensor Actuator.................. 77
3.3.28 Fuser Exit Roller ............................................................................................... 78
3.3.29 Exit Sensor Assy .............................................................................................. 79
3.3.30 Fuser Latching Handle (L)................................................................................ 80
3.3.31 Belt Motor Assy ................................................................................................ 81
3.3.32 Fuser Latching Handle (R) ............................................................................... 82
3.3.33 Main Motor Assy............................................................................................... 83
3.3.34 Main Feeder Drive Motor.................................................................................. 84
3.3.35 Contact Assy/ Left Plate Assy .......................................................................... 85
3.3.36 Low Voltage Power Supply............................................................................... 86
3.3.37 High voltage power supply ............................................................................... 87
3.3.38 Main Feed Assy................................................................................................ 88
3.3.39 Cassette/ Left Guide Assy................................................................................ 89
3.3.40 Cassette/ Right Guide Assy.............................................................................. 90
3.3.41 Fuser Unit ......................................................................................................... 91
3.3.42 Belt Unit ............................................................................................................ 92
3.3.43 Duplex Unit ....................................................................................................... 93
3.3.44 Guide Rails (L) and (R)..................................................................................... 94
3.3.45 Duplex Transport Assembly ............................................................................. 95
3.3.46 CU Assy............................................................................................................ 97
4. ADJUSTMENTS .............................................................................................99
4.1 Maintenance Modes and Their Functions...................................................................... 99
4.1.1 Maintenance menu........................................................................................... 99
4.1.2 Engine maintenance mode............................................................................. 100
4.1.2.1 Operator panel................................................................................... 100
4.1.2.2 General self-diagnosis mode (level 1)............................................. 100
4.1.2.2.1 Entering self-diagnosis mode (level 1) ............................ 100
4.1.2.2.2 Exiting self-diagnosis mode ............................................ 100
4.1.2.3 Switch scan test................................................................................. 101
4.1.2.4 Motor and clutch test ......................................................................... 104
4.1.2.5 Test printing .................................................................................... 106
4.1.2.6 NVM initialization............................................................................ 110
4.1.2.7 Consumable counter display........................................................... 111
4.1.2.8 Consumable counter display - continuous ...................................... 111
4.1.2.9 Error Messages and their Details.................................................... 112
4.1.3 CRM board adjustments................................................................................. 116
4.1.3.1 Short plug settings .......................................................................... 117
4.1.3.2 Printings singly using controller-equipped printer ........................... 117
4.2 Adjustments after Parts Replacement ......................................................................... 118
4.2.1 Precautions in replacing engine controller board ........................................... 118
4.2.2 Precautions in replacing EEPROM................................................................. 118
4.2.3 EEPROM replacement after CRM board replacement................................... 119
4.3 Color Balance Adjustment ........................................................................................... 120
5. PERIODIC MAINTENANCE ......................................................................... 122
5.1 Parts Replaced Periodically ......................................................................................... 122
5.2 Cleaning....................................................................................................................... 122
5.3 Cleaning LED Lens Array ............................................................................................ 122
5.4 Cleaning Pickup Roller................................................................................................. 122

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6. TROUBLESHOOTING PROCEDURES ....................................................... 123
6.1 Before Troubleshooting................................................................................................ 123
6.2 Checking before Troubleshooting Image Problems..................................................... 123
6.3 Precautions in Troubleshooting Image Problems ........................................................ 123
6.4 Preparation for Troubleshooting .................................................................................. 123
6.5 Troubleshooting ........................................................................................................... 123
6.5.1 LCD messages list.......................................................................................... 124
6.5.2 Preparation for troubleshooting ...................................................................... 129
6.5.3 Troubleshooting image problems ................................................................... 140
7. CONNECTION DIAGRAM............................................................................ 154
7.1 Resistance Checks ...................................................................................................... 154
7.2 Program/Font ROM Layouts ........................................................................................ 158
8. Parts List...................................................................................................... 162
APPENDIX A CENTRONICS PARALLEL INTERFACE................................... 178
APPENDIX B 2ND/3RD TRAY MAINTENANCE .............................................. 182

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MMMMMMMM
LED Head
Centronics I/F
USB I/F
2 × Option Slots
Junction Board
Pulse Motor
Engine Control
Low Voltage
Power Unit
Fuser
Unit
High Voltage
Power Unit 2nd/3rdTray
Duplex
Unit
Belt
Unit
<Sensors, Switches and Thermistors>
Paper size sensor (4 bits)
Paper empty sensor
Paper near empty sensor
MT paper empty sensor
FF home switch
Loading sensor 1
Loading sensor 2
C-ID
Unit
M-ID
Unit
Y-ID
Unit K-ID
Unit
C ID M ID Y ID K IDBelt Heat MT/
Registration Hopping
Operator Panel
3 × ROM
DIMMs
4 × RAM
DIMM
IDE
I/F(HDD)
DC Fan
Note
Note Option Slot:
LAN Card made by JCI
1. CONFIGURATIONS
1.1 System Configuration
Figure 1-1 shows the system configuration of the C7000 Series of printers.
Figure 1-1

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1.2 Printer Configuration
The inside of the printers is composed of the followings:
• Electrophotographic Processor
• Paper Paths
• Controller Block (CU and PU)
• Operator Panel
• Power Units (High Voltage Unit and Low Voltage Unit)
Figure 1-2 shows the printer configuration.
Figure 1-2
B
A
B
A
B
A
B

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1.3 Option Configuration
The following options are available for the C7000 Series of printers.
(1) 2nd Tray/ 3rd Tray
(2) Duplex Unit
(3) Expansion Memory 64/128/256 MB
(4) Internal Hard Disk
(5) OkiLAN 6200e NIC

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1.4 Specifications
(1) External Dimensions Height: 16.9 in. Width: 16.9 in. Length: 24.4 in.
(2) Weight 92.5 lbs.
(3) Papers Type: Ordinarypaper,Transparencies(Recommended:MLOHP01)
Size: Postalcard,Legal13"or14",Executive,A4,A5,B5,A6(Only
the 1st tray and the front feeder support A6 and postal-card
sizes.)
Weight:1st tray55 kg to 90 kg (64 to 105g/m2)
Front feeder55 kg to 140 kg (64 to 163g/ m2)
(4) Print Speed Color: 12 pages per minute (Transparency: 5 pages per minute)
Monochrome: 20pagesperminute(Transparency: 12pagesperminute)
Postal Card, Label, Thick Paper: 8 pages per minute
(5) Resolution (C7200) = 600 ×600 -//- (C7400) 1200 x 1200 dots per inch
(6) Power Input 100VAC ±10%
(7) Power Consumption Peak:1300W Normal Operation: 400W (5% duty)
Idle: 110W Power Saving Mode:45W or less
(8) Frequency 50Hz or 60Hz ±2%
(9) Noise Operation: 54 dB (Without second tray)
Standby: 45 dB
Power Saving:43 dB
(10) Consumable Life Toner Cartridge: 10,000 pages (5% duty) (each of Y, M, C and K)
Image Drum: 30,000 pages (Continuous printing)
(each of Y, M, C and K)
(11) Parts Replaced Periodically Fuser Unit Assy: Every 60,000 pages
Transfer Belt Assy: Equivalentof60,000pages(3pages/job)