Xerox Book.P780 Train Tektronix Phaser 780 Color Laser Printer Service Manual Ation

User Manual: Xerox Tektronix - Xerox Phaser 780 Color Laser Printer Service Manual ation La Biblioteca de los 8 bits

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PHASER® 780
COLOR LASER PRINTER
S erv ic e Qu ic k Re fe re n c e Gu id e

Warning
The following servicing instructions are for
use by qualified service personnel only. To
avoid personal injury, do not perform any
servicing other than that contained in
operating instructions unless you are qualified
to do so.
This printing: September 1999
063-3041-01

Copyright © 1998 by Tektronix, Inc., Wilsonville, Oregon. Printed in the United
States of America. All rights reserved. Contents of this publication may not be
reproduced in any form without permission of Tektronix, Inc.
Tektronix®, Phaser®, and Made for Each Other® are registered trademarks of
Tektronix, Inc. TekColor™, PhaserShare™, PhaserMatch™, PhaserLink™,
Finepoint™ and PhaserPrint™ are trademarks of Tektronix, Inc.
RealSUPPORTSM and TekColor CareSM are service marks of Tektronix, Inc.
Other marks are trademarks or registered trademarks of the companies with
which they are associated.

October 1998: First Printing
December 1998: Changed pages; 2, 3, 15, 72, 78, 92, 93, 105, 108, 109, 111, 113, 114,
115, 117, 121, 124, 127, 129, 134, 137, 138, 139, 140, 141, 144, 145
TE/mq/mm

Users safety summary
Terms in
manual:

CAUTION
WARNING

Conditions that can result in damage to the product.
Conditions that can result in personal injury
or loss of life.

Power source: For 110 VAC printers, Do not apply more than 130 volts RMS
between the supply conductors or between either supply conductor and ground.
Use only the specified power cord and connector. For 220 VAC printers, Do not
apply more than 250 volts RMS between the supply conductors or between either
supply conductor and ground. Use only the specified power cord and
connector.Refer to a qualified service technician for changes to the cord or
connector.

Operation of product: Avoid electric shock by contacting a qualified service
technician to replace fuses inside the product. Do not operate without the covers
and panels properly installed. Do not operate in an atmosphere of explosive
gases.
WARNING Turning the power off using the On/Off switch does
not de-energize the printer. You must remove the power cord to
disconnect the printer from the mains. Keep the power cord
accessible for removal in case of an emergency.

Safety instructions: Read all installation instructions carefully before you plug the
product into a power source.
Terms on
product:

CAUTION
A personal injury hazard exists that may not be
apparent. For example, a panel may cover the hazardous area.
Also applies to a hazard to property including the product itself.
DANGER

A personal injury hazard exists in the area where
you see the sign.

Care of product: Disconnect the power plug by pulling the plug, not the cord.
Disconnect the power plug if the power cord or plug is frayed or otherwise
damaged, if you spill anything into the case, if product is exposed to any excess
moisture, if product is dropped or damaged, if you suspect that the product needs
servicing or repair, and whenever you clean the product.
Ground the product: Plug the three-wire power cord (with grounding prong) into
grounded AC outlets only. If necessary, contact a licensed electrician to install a
properly grounded outlet.

Symbols as marked on product:
DANGER high voltage:

Protective ground (earth) terminal:

Use caution. Refer to the manual(s) for information:

!
Laser use caution. Refer to the manual(s) for information:

WARNING: If the product loses the ground connection, usage of knobs and
controls (and other conductive parts) can cause an electrical shock. Electrical
product may be hazardous if misused.

Service safety summary
For qualified service personnel only: Refer also to the preceding Users Safety
Summary.

Do not service alone: Do not perform internal service or adjustment of this product
unless another person capable of rendering first aid or resuscitation is present.
Use care when servicing with power on: Dangerous voltages may exist at several
points in this product. To avoid personal injury, do not touch exposed
connections and components while power is on.
Disconnect power before removing the power supply shield, soldering, or
replacing components.

Do not wear jewelry: Remove jewelry prior to servicing. Rings, necklaces, and
other metallic objects could come into contact with dangerous voltages and
currents.

Power source: This product is intended to operate from a power source that will
not apply more than 250 volts rms between the supply conductors or between
either supply conductor and ground. A protective ground connection by way of
the grounding conductor in the power cord is essential for safe operation.
This product is certified under IEC 825 as a Class 1 Laser Product.

DANGER:

CAUTION:

VORSICHT:

ATTENTION:

Invisible laser radiation
when open and interlock
defeated.
AVOID DIRECT
EXPOSURE TO BEAM.

Invisible laser radiation
when open and
interlocks defeated.
AVOID DIRECT
EXPOSURE TO BEAM.

Unsichtbare Laserstrahlung,
wenn Abdeckung geöffnet
und Sicherheitsverriegelung
überbrückt.
NICH DEM STRAHL
AUSSETZEN.

Rayonnement laser invisible
dangereux en cas
d'ouverture et lorsque
la sécurité est neutralisée.
EXPOSITION DANGEREUSE
AU FAISCEAU.

Class 3B

PELIGRO:

VARNING:

VAROI:

VARNING:

ADVARSEL:

ADVARSEL:

Cuando se abre y se
invalida el bloqueo, se
producen radiaciones
invisibles de láser.
EVITESE LA
´
EXPOSICION
DIRECTA A TALES
RAYOS.

Osynlig laserstrálning när denna
del är öppnad och
spärrar är
urkopplade.
STRÅLEN
ÄR FARLIG.

Näkymätön
avattaessa ja
suojalukitus
ohitettaessa olet
alttiina lasersäteilylle.
ÄLÄ KATSO
SÄTEESEN.

Osynlig laserstrálning
när denna del är
öppnad och spärrar är
urkopplade.
BETRAKTA EJ
STRÅLEN.

Usynlig laserstràling
ved abning når
sikkerhedsafbrydere
er ude af funktion.
UNDGÅ UD
ÆTTELSE FOR
STRÅLING.

Usynlig laserstraling
nar deksel åpnes og
sikkerhedslas brytes.
UNNGÅ
EKSPONERING
FOR STRÅLEN.
PJQT4521ZA

9008-78

Contents
General Information

1

Phaser 780 overview 2
Memory considerations 3
Print engine assemblies 5
The image processor 10
Front panel 11
Rear panel 12
Network card LEDs 12
Specifications 14
Regulatory specifications 17
Safety 17
EMC 17
Energy Star certification 17

Error Codes and Messages
Troubleshooting

19

39

System power-up sequence 39
Print engine troubleshooting 40
Printer will not power up 40
Erratic printer operation 41
Making a print engine only test print 42
Printing and print quality problems 43
Initial checks and actions 43
Light (undertone) prints 44
Blank prints 45
Monochrome prints 46
Black prints 47
One color is faded 47
Missing band in direction of paper travel 48
Missing bands in parallel to the leading edge 49
Streaks in direction of paper travel 51
Streaks parallel with the leading edge 52
Banding 53
Edge of print is wrinkled with an area of ragged discoloration.
Random missing spots 54
Random spotting 55
Repetitive mark appears on each print 56
Residual image or ghosting 56
Background contamination 57
Unfused image or image easily rubs off of page 58
Toner on back of print 58

Service Guide

53

vii

Print is mottled 59
Image mis-registered on paper 60
Color layer not correctly registered 60
Color representation not correct 61
Oil stain or gloss variation on print 61
Random spotting 62
Media jams and the paper path 63
Skewed image 63
Damaged prints 64
Inoperative lower tray feeder 65
Power problems 65
All front panel indicators remain off. The printer does not initialize
upon power-up 65
Front panel indications 66
Media tray indicates missing or empty when it is not 66
Macintosh printing problems 66
Image never prints 66
Image prints in black-and-white 66
Image is rotated 90 degrees 67
Windows printing problems 67
Image never prints 67
Blue color on the screen is printing too purple. 67
Printing from Windows 3.1 produces the message “Problem writing
device LPT1: Cancel or Retry”. 68
Workstation printing problems 68
Image never prints 68
Running built-in diagnostics 69

Adjustments

73

Printing test prints 73
Print service test prints 73
Printing the configuration page 73
Printing the demonstration pages 73
Print engine calibration 74
Adjusting for impulse banding 74

Cleaning and Maintenance

77

Service preventive maintenance procedure
Recommended tools 77
Cleaning 78

Resetting NVRAM

viii

79

Phaser 780 Color Printer

77

Key FRU Disassembly

81

Paper feeder 82
Feeder registration chute 83
Feeder registration clutch 84
Registration brake clutch 85
Feeder metal registration roller 86
Feeder rubber registration roller 87
Feeder pre-registration clutch 88
Feeder pre-registration rollers 89
Paper-pick turn roller 91
Paper feed drive gear train 92
Paper-feed motor 93
Multi-purpose tray roller assembly 94
Multi-purpose tray pick rollers 95
Auto-density calibration sensor 97
Developer assembly 99
Developer clutch 101
Developer tie plate 102
Toner/developer dispense motor 104
Carousel assembly 105
Carousel motor 107
Carousel motor board 108
Carousel sensor 109
Laser unit 110
Erase lamp rail assembly 112
Erase lamp 114
Process drive unit 115
Waste auger assembly 117
Accumulator belt assembly 119
Accumulator belt cleaner assembly 121
Second bias transfer roller assembly 122
Second bias transfer roller cam assembly 123
Fuser assembly 125
Fuser drive gear train 126
Lower exit assembly 128
Full stack sensor 130
Low voltage power supply 131
High voltage power supply 132
Image processor 133
Image processor chassis 134
Print engine control board 135

Service Guide

ix

FRU List

137
Supplies and accessories

Test Prints

179

Wiring Diagrams

x

185

Phaser 780 Color Printer

176

Figures
The Phaser 780 printer (shown with optional Lower Tray Assembly) 1
Internal features of the print engine 5
Circuit boards of the print engine 6
Motors of the print engine 7
Sensors and switches on the print engine 8
Solenoids and clutches on the print engine 9
Features of the image processor board 10
Printer front panel 11
Printer rear panel with the optional Ethernet card 13
Adjusting for impulse banding 75
Removing the paper feeder 82
Removing the registration chute 83
Removing the registration clutch 84
Removing the registration brake clutch 85
Removing the metal registration roller 86
Removing the rubber registration roller 87
Removing the feeder pre-registration clutch 88
Removing the feeder pre-registration roller 90
Removing the paper-pick turn roller 91
Removing the paper-feed drive gear train 92
Removing the paper-feed motor 93
Removing the multi-purpose tray roller assembly 94
Removing the multi-purpose tray pick rollers 96
Removing the auto-density calibration sensor 98
Removing a developer assembly 100
Removing the developer clutch 101
Removing the developer tie plate 103
Removing the toner/developer dispense motor 104
Removing the carousel assembly 106
Removing the carousel motor 107
Removing the carousel motor board 108
Removing the carousel sensor 109
Removing the laser unit 111
Removing the erase lamp rail assembly 113
Removing the erase lamp 114
Removing the process drive unit 116
Removing the waste auger assembly 118
Removing the accumulator belt assembly 120
Removing the accumulator belt cleaner assembly 121
Removing the second bias transfer roller assembly 122

Service Guide

xi

Removing the second bias transfer roller cam assembly 124
Removing the fuser assembly 125
Removing the fuser-drive gear train 127
Removing the lower exit assembly 129
Removing the stack full sensor 130
Removing the low voltage power supply 131
Removing the high voltage power supply 132
Removing the image processor 133
Removing the image processor chassis 134
Removing the print engine control board 135
Printer cabinet FRUs 138
Paper feeder FRUs 140
Multi-purpose tray cover FRUs 142
Multi-purpose tray FRUs 144
Paper feeder cover FRUs 146
Paper feeder FRUs 148
Imaging FRUs 150
Developer FRUs 152
Carousel FRUs 154
Accumulator belt assembly FRUs 156
Fuser assembly FRUs 158
Paper exit FRUs 160
Paper exit FRUs 162
Drive FRUs 164
Electronic (rear) FRUs 166
Electronics (front) FRUs 168
Image processor FRUs 170
Optional lower feeder cabinet FRUs 172
Optional Feeder FRUs 174
Print engine wiring diagram 185
Map 1 – Wiring routing at the top and front of the printer 193
Map 2 – Wire routing around the engine control board 194
Map 3 – Wiring routing around the image processor board 195
Map 4 – Wiring routing around the paper feeder 196
Map 5 – Wire routing around the laser scanner and high voltage power supply 197
Map 6 – Wire routing at the rear of the printer 198
Map 7 – Wire routing around the power supply 199
Map 8 – Wire routing around the fuser 200
Wiring 1 – Low voltage power supply, laser unit, and interlock switches 201
Wiring 2 – Engine control board, auto-density calibration sensor, erase lamp, waste
toner sensor 202
Wiring 3 – Low voltage power supply, engine control board, high-voltage power
supply and imaging components 203

xii

Phaser 780 Color Printer

Wiring 4 – Engine control board, used cartridge sensor, cartridge sensor, carousel
sensor, developer clutch, developer fan, toner dispense motor 204
Wiring 5 – Engine control board, low voltage power supply, carousel motor board,
rotary motor 205
Wiring 6 – Engine control board, low voltage power supply, bias transfer roller cam
solenoid accumulator belt sensor, paper feeder motor, process motor 206
Wiring 7 – Engine control board, low voltage power supply, fuser, oil roll assembly
207
Wiring 8 – Engine control board, fuser assembly, environment sensor 208
Wiring 9 – Engine control board, paper size switch board, feed solenoid, no paper
sensor, low paper sensor 209
Wiring 10 – Engine control board, paper feeder 210
Wiring 11 – Engine control board, paper feeder, multi-purpose tray 211
Wiring 12 – Engine control board, top exit sensor, media exit switch, full stack sensor,
fuser fan 212
Wiring 13 – Engine control board, image processor board, front panel, image processor
fan 213
Wiring 14 – Lower Tray Assembly master wiring diagram 214
Wiring 15 – Engine control board and low voltage power supply to Lower Tray
Assembly feeder board 215
Wiring 16 – Lower Tray Assembly feeder board to feeder chute switch, size switches
and feeder motor 216
Wiring 17 – Lower Tray Assembly feeder board to no paper sensors and low paper
sensors 217
Wiring 18 – Lower Tray Assembly feeder board to feed solenoids and turn chutes 218

Service Guide

xiii

Tables
Memory and features sets 3
Physical dimensions of printer 14
Physical dimensions of lower tray feeder 14
Printer clearances 14
Functional specifications 15
Electrical specifications 16
Environmental specifications 16
Diagnostic tests 69
Printer cover FRUs 139
Paper feeder FRUs 141
Multi-purpose tray cover FRUs 143
Multi-purpose tray FRUs 145
Paper feeder cover FRUs 147
Paper feeder FRUs 149
Imaging FRUs 151
Developer FRUs 153
Carousel FRUs 155
Accumulator belt assembly FRUs 157
Fuser assembly FRUs 159
Paper exit FRUs 161
Paper exit FRUs 163
Drive FRUs 165
Electronic (rear) FRUs 167
Electronic (front) FRUs 169
Image processor FRUs 171
Optional lower feeder cabinet FRUs 173
Optional feeder FRUs 175
Supplies and accessories 176
Plug/Jack Locations - 1 186
Plug/Jack Locations - 2 187
Plug/Jack Locations - 3 188
Plug/Jack Locations - 4 189
Plug/Jack Locations - 5 190
Plug/Jack Locations - 6 191
Plug/Jack Locations - 7 192

xiv

Phaser 780 Color Printer

General Information
This service guide contains information useful to verify operation, troubleshoot,
repair, adjust, and maintain a Tektronix Phaser® 780 Color Printer.
To ensure complete understanding of the product, we recommend participation
in Phaser 780 service training, if available.

3041-01

The Phaser 780 printer (shown with optional Lower Tray Assembly)

Service Guide

1

Phaser 780 overview
The Phaser 780 Color Printer combines a color laser, continuous-tone print engine
with an image processor supporting Adobe’s PostScript 3 page description
language. The image processor features a bi-directional parallel interface and a
10baseT Ethernet port for host communication. Optional network adapter cards
to the image processor allow the printer to communicate on networks using
LocalTalk, Ethernet 100baseT or Token Ring protocols. The Ethernet network
card supports EtherTalk 100baseT, Novell and TCP/IP. With the Token Ring
network card, the printer supports Token Ring protocols. The network cards are
sometimes referred to as “smart cards” because each houses its own processor for
executing specific on-board protocols; only data is transferred from the installed
smart card to the printer’s image processor board. The PCL printer language is
also supported.
The printer is marketed in three versions:
The Phaser 780 N (Standard) comes standard with 64 Mbytes of RAM. The
printer contains 136 standard, built-in fonts. The standard Phaser 780 prints at a
resolution of 600 x 600 dots-per-inch on A and B-size media. The base printer
does not support grayscale printing.
The Phaser 780 GN (Graphics) features 96 Mbytes of RAM and can print at
600 x 1200 dpi. It also contains 136 fonts. The graphics printers supports 16 level
grayscale printing as well as printing oversize-B images.
The Phaser 780 P (Plus) features 192 Mbytes of RAM and supports the same
features as the GN printer. In addition, the Plus version Phaser 780 supports
image pipelining for greater throughput, a print collation mode, and a “check
print before proceeding with job” mode. The plus printer also feature a SCSIcompatible interface to connect to an external hard disk drive for additional font
storage. The hard disk drive is also required for print collation of multiple copy
multi-page prints. A scanner can also be connected to the Plus printer’s SCSI port
to give the printer the ability to optically copy color images.
RAM memory in the printers can be supplemented with one or two additional 32, 64-, or 128-Mbyte RAM DIMMs; the maximum usable capacity is 192 Mbytes
Print speeds depend on the chosen resolution and selected media. For resolutions
of 600 x 600 (standard), in color, the printer prints at 4 A-size pages per minute
(ppm) on paper. Monochrome printing (Fast Monochrome) is at 16 ppm on paper.
Transparency film printing is always 2 ppm.
The printers support printing on A-, A4-, A5-, B-, B4, B5, SRA3, A3-, 13 x 19 in.
and Legal-sized paper from a 250-sheet tray. An optional three-tray second feeder
(called the Lower Tray Assembly) is available with additional 250-sheet standard
media trays. The printer features a built-in multi-purpose tray from which
specialty media, cardstock and envelopes can be fed. The printer also supports
manual feeding using the multi-purpose tray.
After being idle for the selected amount of time the printer switches into its
Energy Star mode where it consumes less than 45 watts of power. It “awakens”
upon receiving data at any of its ports.

2

Phaser 780 Color Printer

Memory considerations
The base printer features 32 Mbytes of RAM in one connector and features two
additional DIMM connectors which accept 16-, 32-, 64-, or 128 Mbytes RAM
DIMMs. The printer can use any off-the-shelf RAM meeting these specifications:
■

168 pin DIMM

■

Synchronous DRAM

■

3.3 volt

■

9 nsec speed

■

Valid on-board Serial Presence Detect ROM.

Upon power-up, the image processor interrogates the 256 byte Serial Presence
Detect ROM which describes the DIMM in great detail, with details such as data
width, clock delay, number of address columns and row, refresh rate and more. If
the DIMM does not meet the required specifications it will be ignored; no error
message will be reported.
With more memory the printer gains the capabilities of printing at higher
resolutions, printing without having to use image compression (which trades off
less installed RAM for longer image processing time) and dual frame buffers for
printing one image while processing a second image (which gives greater
printing throughput). With additional RAM memory, the printer’s capabilities
increase as detailed in the following table:
Table 1 Memory and features sets
Configuration/ options

“Standard”
printer
w/ 64 Mbyte
RAM

“Graphics”
printer
w/ 96 Mbyte
RAM

“Plus” printer
w/ 192 Mbyte
RAM

600 x 600 with full image
area

Yes

Yes

Yes

600 x 1200 with full
image area

No

Yes

Yes

Check Print/ PhaserMatch

No

No

Yes

Job Pipelining

No

No

Yes - 2 pages

Parallel port buffer

256 kbytes

256 kbytes

512 kbytes

Print Collation - requires
hard drive option

No

No

Yes

Fonts available

136

136

136

Service Guide

3

Print the Configuration Page and check the item “installed RAM” to see what
type of RAM is installed.
For example:
Installed RAM: 96 Mbytes
Mem slot 1: SDRAM/parity/64 MB/KMM366S824AT
Mem slot 1: empty
This is a list of DRAM SIMMs that are branded for use by Tektronix at the time
this guide was published:
Size

Maker

Part Number

16 Mbyte

Samsung

KMM366S203BT

32 Mbyte

Samsung

KMM366S403BT

64 Mbyte

Samsung

KMM366S824AT

128 Mbyte

Samsung

KMM366S1623AT

32 Mbyte

Smart Module

SM564043574N6AA

64 Mbyte

Smart Module

SM564088574N6AA

32 Mbyte

NEC

MC-454AD645F-A10B

64 Mbyte

NEC

MC-454CB645FA-A10B

128 Mbyte

NEC

MC-4516CD645FZ-A10B

16 Mbyte

Micron Tech.

MT8LSDT264AG-66CL2

32 Mbyte

Micron Tech.

MT16LSDT264AG-10BC4

32 Mbyte

Micron Tech.

MT16LSDT264AG-662C1

64 Mbyte

Micron Tech.

MT8LSDT864AG-662D3

64 Mbyte

Micron Tech.

MT8LSDT864AG-10BD2

128 Mbyte

Micron Tech.

MT16LSDT1664AG-662DT

4

Phaser 780 Color Printer

Print engine assemblies
Developer
assemblies

Laser
unit

Carousel
assembly
Paper
feeder
Fuser
Media
tray 1

Multi-purpose
tray
Accumulator
belt cleaner

Imaging unit
Second bias
transfer roller
Accumulator
belt assembly

3041-02

Internal features of the print engine

Service Guide

5

.
Image
processor
board
Engine
control
board

Carousel
motor
board

Network
card

Circuit boards of the print engine

6

Phaser 780 Color Printer

High Voltage
board

Low Voltage
Power Supply (LVPS)
3041-04

Image processor
fan
Process drive
assembly

Toner
dispense
motor

Developer fan

Fuser fan

Carousel
motor
Paper
feed drive
gear train
Process
motor

Paper feed
motor
3041-03

Motors of the print engine

Service Guide

7

Exit
sensor

Exit door
sensor

Used toner
cartridge
sensor

Auto-density
calibration
sensor

Full
stack
sensor

Top cover
switch

Carousel
sensor
Right front
cover switch
Waste cartridge
full sensor
Waste cartridge
sensor

Left front
cover
switch

Accumulator
belt home
sensor

Toner
cartridge
presence
sensor

Paper size
sensor

Fuser
temperature
sensor

Edge
sensor

Multi-purpose
tray paper
present sensor

Fuser exit
sensor

Long paper
sensor
Environment
sensor

Registration
sensor

Sensors and switches on the print engine

8

Phaser 780 Color Printer

Low paper
sensor
Paper empty
sensor
3041-05

Registration
clutch
Second bias
transfer roller
solenoid

Developer clutch

Pre-Registration
clutch

Registration
brake clutch

Multi-purpose
pick-up solenoid
Multi-purpose
tray clutch

3041-06

Solenoids and clutches on the print engine

Service Guide

9

The image processor

Real Time Clock / NVRAM

RAM
DIMMS

SCSI
riser
card
NVRAM

Network
card

Boot
ROM

Font
DIMM

Postscript
code ROM
DIMM
3041-07

Features of the image processor board

10

Phaser 780 Color Printer

Front panel
These front panel features are found on the printer:
■

A two-line, 40-character LCD

■

Six push buttons

■

Five LEDs

LCD. The LCD serves two purposes: Displaying current image processor and
print engine status information and displaying an interactive menu. Status
information includes image processor status such as Ready, Processing and
Printing. Print engine status includes messages such as Out of paper, Paper
Jam, and Toner Low.
The interactive menu can only be entered while the printer is idle and ready. The
interactive menu has two modes, review and modify. Customers can review and
modify certain NVRAM, I/O ports and peripheral parameters.

Buttons. Button 6, the left-most button, is an Exit key used to cancel an operation
while in the interactive menu. The functions of the remainder of the buttons are
defined by the particular menu or function being displayed on the LCD. The
bottom row of the LCD labels the current function of each button.

Ready
Print

Menu

Select

3041-18

Printer front panel

Service Guide

11

Rear panel
Connectors
The rear panel of the printer features the host interface connectors:
■

Bi-directional parallel (high-density connector).

■

Twisted Pair 10baseT Ethernet connector. RX indicator (green); blinks
while the network card is receiving data. The LED is off steady while no
data is being received. If the LED is on steady, then a problem (probably
hardware) has occurred at the network hub.

■

SCSI high-density connector (external hard disk drive or optical scanner
only).

With the addition of a network card, the printer can feature either of these groups
of connectors:
■

ThinNet (100base2) and Twisted Pair (100baseT) Ethernet connectors.
This is Option P1.

■

LocalTalk connector. This is Option P3.

■

Unshielded Twisted Pair (10baseT) and shielded Twisted Pair (DB-9)
Token Ring connectors. This is Option P4.

Network card LEDs
The Ethernet network card has four LED indicators:
■

TX indicator (yellow); blinks while data is transmitted to the host. The
LED is off while no data is being sent.

■

Twisted Pair (100baseT) and ThinNet (100base2). RX indicator (green);
blinks while the network card is receiving data. The LED is off steady
while no data is being received. If the LED is on steady, then a problem
(probably hardware) has occurred at the network hub.

■

TP Link. On steady indicates good circuit to nearest port; off indicates
no circuit.

■

100 MBS. Ethernet speed is 100 MBS when lit.

Note

12

Do not use both Ethernet connectors at the same time. With a
Ethernet or Token Ring network card installed, the 10baseT port
is disabled.

Phaser 780 Color Printer

The Token Ring network card has two LED indicators:
■

Connection (yellow); off when the printer is not inserted into the Token
Ring, blinks while the printer is attempting to insert itself into the Token
Ring, on when the printer is properly inserted in the ring.

■

Ring Speed (green); off when the card is set for 4 megabits-per-second
(MBPS), on when the card is set for 16 MBPS.

■

When both LEDs blink, a network card failure has occurred.

The following figure illustrates the rear panel of the printer.

SCSI port
Parallel port
10 base T ethernet port

Ethernet
card

TX

RX

16
Mbs

INS
UTP

LocalTalk®

STP

LocalTalk
card

PhaserShareTM
Series B
Token Ring Card

RX

TX

PhaserShareTM
Series B
LocalTalk Card

TX

PhaserShareTM
Series B
Ethernet Card

RX

100
Mbs

TP
LINK

10/100Base-TX

10Base2

Slot for network card & IDE hard drive

Token Ring
card

Internal
hard drive
3041-08

Printer rear panel with the optional Ethernet card

Service Guide

13

Specifications
Table 1 Physical dimensions of printer
Dimension

Value

Height

49.2 cm (19 in) without lower tray feeder
90.6 (36 in) with lower tray feeder

Width

69.1 cm (27.2 in)

Depth

64.1 cm (24.2 in)

Weight

73.6 kg (161 lbs) with consumables installed
97.1 kg (213 lbs) with lower tray feeder and consumables

Table 2 Physical dimensions of lower tray feeder
Dimension

Value

Height

41.4 cm (16.3 in)

Width

56 cm (22 in)

Depth

56 cm (22 in)

Weight

23.5 kg (52 lbs)

Table 3 Printer clearances
Dimension

Value

Top

40.0 cm (15.7 in)

Left

50.3 cm (20 in)

Right

55.1 cm (21.5 in)

Front

83.5 cm (33 in)

Rear

15.0 cm (6 in)

Bottom

No obstructions underneath that could block cooling vents

Mounting surface flatness

Front feet less than 5 mm above or below rear feet
Left feet less than 10 mm above or below right feet

Mounting surface dimensions

Level surface with dimensions of at least 79 cm (31 in.) by
152 cm (60 in.).

14

Phaser 780 Color Printer

Table 4 Functional specifications
Characteristic

Specification

Printing process

Electro-photographic, four color (CMYK), two transfer printing using
modulated (on/off) laser beam scanning. Imaged is fused to paper
using heat and pressure with silicone oil lubricant.

Color medium

Four toner cartridges each containing one of four colors: cyan,
magenta, yellow or black. The toner is a nonmagnetic, dual
component contact medium.

Addressability

600 x 600 dpi and 600 x 1200 dpi

Print speed

Time from paper load to paper eject:
A-size:
Four color: 4 pages per minute
Monochrome: 16 pages per minute
Transparency: 2 pages per minute
B-size:
Four color: 2 pages per minute
Monochrome: 8 pages per minute
Transparency: 1 page per minute

Minimum margins

5 mm(0.2 in.) on all sides, except for Tabloid Plus (13 x 19 in.)
media which has a bottom margin of 25 mm (1 in.)

Usable papers sizes

Paper:
Envelope:
3.5x5.5, minimum size
US #10
8.5x11, Letter
Euro Standard
8.5x14, Legal
A4
11x17, Tabloid
C4
12x18, Tabloid Extra
C5
13x19, Tabloid Plus
C6
A3
C65
A4
A5
B4
B5
Avery label: 5164, 5663, 7330, 7348

Usable paper weights

75 to 105 g/m2 (20 to 24 lb) thru paper tray.
64 to 220 g/m2(80 lb) using the multi-purpose tray

Tray capacities

Main tray:
Standard paper: 250 sheets
Transparency: 100 sheets
Lower feeder trays:
Standard paper: 250 sheets
Multi-purpose tray:
Standard paper/Letterhead: 150 sheets
Transparency: 50 sheets
Label: 50 sheets
Postcard: 75
Envelope: 30
Glossy/Coated: 75
Index: 30
Fabric Transfer: one at a time

Service Guide

15

Table 5 Electrical specifications
Characteristic

Specification

Primary line voltage

100/120 VAC (+/- 10%)
220/240 VAC (+/- 10%)

Primary voltage frequency
range

47 to 63 Hz

Power consumption

EnergyStar: 20 watts
Standby: 100 watts
1000 watts with fuser on
Ready: 100 watts
1000 watts with fuser on
Printing: 1100 watts

Table 6 Environmental specifications
Characteristic

Specification

Temperature:
Operating
Non-operating
Storage

0 to 32oC (41 to 90oF)
-20 to40oC (-4 to 104oF)
-20 to40oC (-4 to 104oF)

Humidly:
Operating
Non-operating
Storage

15 to 85% relative humidity
5 to 85% relative humidity
5 to 85% relative humidity

Altitude
Operating:
Non-operating

0 to 3000 m (9900 ft.) at 25oC
0 to 15000 m (50,000 ft.)

Vibration
Operating:

Shock-non-operating

Will withstand 0.5G excitation, 5 to 100 Hz, 3 axes for up to 50 minutes
with no impairment or subsequent damage.
0.5 g, 25 minute sweep, 5-100 Hz, 100-200 sec/sweep cycles
The printer may have any corner raised and dropped 5 cm (2 in.)
without impairment of operation.

Acoustic Noise
Idle:
Printing:

38.3 db
54.8 db with impulse noise of 63.3 db

Non-operating

16

Phaser 780 Color Printer

Regulatory specifications
Safety
■

EN60950 CB Report by Third Party GOST and TUV certification

■

UL1950 Nationally Recognized Test Lab (NRTL) certified

■

CSA 950 SCC recognized test lab certified

EMC
■

EN55022 (CISPR 22) Class B

■

EN50082-1:1994 Susceptibility

■

EN61000-3-2 AC Mains Harmonic Distortion

■

EN61000-3-3 AC Mains Voltage Flicker

■

EN61000-4-2:1993 ESD

■

EN61000-4-4:1993 Fast Burst Transients

■

EN61000-4-5:1993 Line Surge

■

EN61000-4-11;1993 Voltage Dips and Interruptions

■

ENV50140:1993 Radiated RF Immunity

Energy Star certification
After 1-hour period of inactivity, the printer enters an standby mode, as required
by Energy Star. The wait time is a user-definable parameter (via the front panel or
by using PhaserLink). Energy Star default is “ON” and the time-out default is
one hour. The printer enters a READY condition within 5 minutes after poweron.

.

Service Guide

17

18

Phaser 780 Color Printer

Error Codes and
Messages
The following table list error codes and messages reported by the print
engine control board.
Error code
and
message

Description

Corrective action

Laser Unit
Error
(Error 10)

There is a problem with the laser unit.
The engine control board did not receive
a signal from the laser start-of-scan
sensor within the specified time

1. Test the top cover and right

Image
Density Error
(Error 11)

The image density readings indicate a
problem. The engine control board
detected that the printer image density
was unusually low and attempts to raise
the density have failed.
Note

If the top cover is removed,
light can leak into the printer
and cause a auto-density
calibration sensor error.

front cover switches for
proper operation. Power for
the laser unit is routed
through both switches
2. Replace the laser unit.
3. Replace the engine control
board
1. Power cycle the printer
2. Inspect the toner cartridges.
3. Inspect the four developer

4.

5.

6.

7.
8.
9.

housings. Each magnetic
roller should be evenly
coated with toner. Replace a
suspect developer assembly.
Test the toner/developer
dispense motor. Replace it if
it does not run
Inspect and reseat the
auto-density calibration
sensor. Ensure the senor’s
solenoid-activated cleaning
blade is in place and moves
freely.
Test the auto-density
calibration sensor. If bad,
replace the auto-density
calibration sensor
Replace the imaging unit
Replace the engine control
board
Replace the high voltage
board

Service Guide

19

Error code
and
message

Description

Corrective action

Image
Density Error
(Error 12)

The image density readings indicate a
problem. The engine control board
detected that the printer image density
was unusually high and attempts to
lower the density have failed.

1. Power cycle the printer
2. Ensure the toner cartridges

20

Phaser 780 Color Printer

are fully functional and
relatively full of toner.
3. Test the toner dispense
motor.
4. Check the auto-density
calibration sensor for
contamination from toner.
Replace the sensor, if
necessary.
5. Inspect and reseat the
auto-density calibration
sensor. Ensure the senor’s
solenoid-activated cleaning
blade is in place and moves
freely.
6. Test the auto-density
calibration sensor. If bad,
replace the auto-density
calibration sensor
7. Replace the engine control
board
8. Inspect the four developer
housings. Each magnet
roller should be evenly
coated with toner. Replace a
suspect developer assembly.
9. Replace the imaging unit
10. Replace the high voltage
board

Error code
and
message

Description

Corrective action

Autodensity
Calibration
Error
(Error 13)

There is problem with the auto-density
calibration. The engine control board
detected that the auto-density
calibration sensor LED output signal is
below specified range.

1. Power cycle the printer
2. Check the auto-density

3.

4.

5.
6.

Toner
Carousel
Error
(Error 21)

There is a problem with the carousel
home sensor. The engine control board
detected that the carousel home sensor
did not actuate within six seconds after
the start of the carousel motor.

calibration sensor for
contamination from toner.
Replace the sensor, if
necessary.
Inspect and reseat the
auto-density calibration
sensor. Ensure the senor’s
solenoid-activated cleaning
blade is in place and moves
freely.
Test the auto-density
calibration sensor. If bad,
replace the auto-density
calibration sensor
Replace the engine control
board
Replace the low voltage
power supply

1. Power cycle the printer
2. Manually rotate the carousel

assembly several revolutions
3. Check for contamination that

may cause binding.
4. Test the carousel home

sensor. Replace if needed
5. Replace the carousel motor
6. Replace the engine control

board
PCDC Error
(Error 22)

There is a problem with PCDC
calibration. The engine control board
detected that PCDC calibration value is
much lower than set specifications.

1. Power cycle the printer
2. Inspect the process drive.

Ensure the drum rotates
3. Replace the engine control

board
4. Replace the image processor

board
Environment
Sensor Error
(Error 23)

There is a problem with the environment
sensor circuit. The engine control board
detected an open environment sensor
circuit

1. Power cycle the printer
2. Replace the environment

sensor
3. Replace the engine control

board

Service Guide

21

Error code
and
message

Description

Corrective action

Second Bias
Transfer
Roller Error
(Error 24)

The engine control board detected that
the measured current value thru the
second bias transfer roller was not within
specification.

1. Check the wiring from the

2.
3.
4.

5.

Fuser
Temperature
Error
(Error 40)

There is a problem with the temperature
of the fuser. The engine control board
detected that the fuser temperature did
not reach 110˚C within six minutes after
the printer was turned on.

1. Open the fuser door and

2.

3.

4.
5.

Fuser
Temperature
Error
(Error 41)

There is a problem with the fuser heat
rod control. The engine control board
detected that the fuser heat rods
remained on longer than the specified
time.

2.

4.
5.

Phaser 780 Color Printer

ensure the fuser connectors
are properly seated.
Close the fuser and power
cycle the printer. Check that
the fuser heats up
Check for line voltage at P/J
71 pins 1 and 2. If no voltage
is present replace the power
supply
Replace the fuser
Replace the engine control
board

1. Open the fuser door and

3.

22

high voltage power supply to
the second bias transfer roller
Replace the second
bias transfer roller
Replace the high
voltage power supply
Replace the
accumulator belt
assembly
Replace the engine
control board

ensure the fuser connectors
are properly seated.
Close the fuser and power
cycle the printer. Check that
the fuser heats up
Check for line voltage at P/J
71 pins 1 and 2. If no voltage
is present replace the power
supply
Replace the fuser
Replace the engine control
board

Error code
and
message

Description

Corrective action

Fuser
Temperature
Error
(Error 42)

There is a problem with the fuser. The
engine control board senses an open
temperature sensor circuit.

1. Open the fuser door and

2.

3.

4.
5.

Fuser
Temperature
Error
(Error 43)

There is problem with the fuser. The
engine control board detected that the
fuser did not reach ready temperature
during the specified time.

1. Open the fuser door and

2.

3.

4.
5.

Fuser
Temperature
(Error 44)

The thermistor sensor indicates that the
fuser had reached the set overheat
temperature, The engine control board
has shutdown fuser temperature
operation.

ensure the fuser connectors
are properly seated.
Close the fuser and power
cycle the printer. Check that
the fuser heats up
Check for line voltage at P/J
71 pins 1 and 2. If no voltage
is present replace the power
supply
Replace the fuser
Replace the engine control
board
ensure the fuser connectors
are properly seated.
Close the fuser and power
cycle the printer. Check that
the fuser heats up
Check for line voltage at P/J
71 pins 1 and 2. If no voltage
is present replace the power
supply
Replace the fuser
Replace the engine control
board

1. Allow the fuser to cool for 30

minutes
2. Ensure the fuser wiring

harnesses are plugged in.
3. Check the fuser fan
4. Replace the fuser
5. Replace the engine control

board
6. Replace the low voltage

power supply

Service Guide

23

Error code
and
message

Description

Corrective action

Process
Motor Error
(Error 61)

There is a problem with the process
motor. the engine control board did not
receive a signal from the accumulator
belt home sensor signal in the specified
time.

1. Test the process drive

assembly
2. Test the +24 VDC at P/J

32-11 and frame ground.
3. Test the accumulator belt

home sensor
4. Replace the process motor.
5. Replace the accumulator belt

assembly
6. Replace the engine control

board
7. Replace the imaging unit

Paper
Handling
Motor Error
(Error 62)

There is a problem with the paper feed
motor. The engine control board
received a failed signal from the paper
feed motor circuitry.

1. Power cycle the printer
2. Replace the paper feed

motor
3. Replace the engine control

board
4. Check for mechanical binding

in the paper feed drive gear
train
Imaging Unit
ID Error
(Error 69)

The engine control board detected a
used CRUM

1.
2.
3.
4.

Reseat the imaging unit
Power cycle the printer
Replace the imaging unit
Replace the engine control
board

Imaging Unit
ID Error
(Error 70)

There is a CRU Memory problem. The
engine control board detected that the
memory initial value of the installed
imaging unit is wrong.

1.
2.
3.
4.

Reseat the imaging unit
Power cycle the printer
Replace the imaging unit
Replace the engine control
board

Imaging Unit
ID Error
(Error 71)

An incompatible imaging unit is installed
in the printer. The engine control board
detected that the memory device in the
installed imaging unit is incompatible
with the printer.

1. Power cycle the printer
2. Reseat the imaging uni
3. Switch the printer power off,

There is a CRU memory problem. The
engine control board could not read the
CRUM counter value.

1. Power cycle the printer
2. Replace the imaging unit with

Imaging Unit
Count Error
(Error 72)

then on
4. Replace the engine control

board

a new cartridge
3. Replace the engine control

board
24

Phaser 780 Color Printer

Error code
and
message

Description

Corrective action

Imaging Unit
ID Error
(Error 73)

The wrong imaging unit is installed in
the printer. The engine control board
detected that the installed imaging unit
is incompatible with the printer.

1. Power cycle the printer
2. Replace the imaging unit with

There is a CRU memory problem. The
engine control board could not write to
the CRUM.

1. Power cycle the printer
2. Reseat the imaging unit in the

Imaging Unit
Comm Error
(Error 74)

a new cartridge
3. Replace the engine control

board

printer
3. Replace the imaging unit with

a new cartridge
4. Replace the engine control

board
Imaging Unit
Comm Error
(Error 75)

There is a CRU Memory problem. The
engine control board could not
communicate with the CRUM.

1. Power cycle the printer
2. Replace the imaging unit with

a new cartridge
3. Replace the engine control

board
Engine
Board Error
(Error 76)

The engine control board detected a
corrupted NVRAM during power-on self
test

1. Power cycle the printer
2. Replace the NVRAM

chip
3. Replace the engine control

board
ROM/
RAM Error
(Error 77)

There is a problem in reading
information from ROM or RAM on the
engine control board. The engine control
board could not read information on the
ROM or RAM.

1. Power cycle the printer
2. Check if +5 VDC is supplied

at P/J33-3 and frame ground.
If not, replace the low voltage
power supply
3. Replace the engine control
board

Service Guide

25

Error code
and
message

Description

Corrective action

Image
Contains Too
Much
Coverage

Image density exceeded design
specifications.
The engine control board detected that
the first 70mm of the lead edge of the
four color image about to be printed
exceeds the design specification for total
image density. The specification is 280%
or less image density. For example, a
density setting of 100% for each of the
four colors creates a layered four color
image with a combined density of 400%.

1. Power cycle the printer
2. Print a less complex, color

Replace
Fuser Roll
Cartridge

The fuser oil roll has reached end of life.
The engine control board detected that
the fuser oil roll has processed the
equivalent of 20,000 sheets of paper
since it was installed.

1. Replace the fuser roll

image to determine if it is
overly dense.
3. Replace the engine control
board

cartridge
2. Power cycle the printer
3. Ensure the fuser connectors

are properly seated
4. Test the fuser using internal

diagnostics
5. Replace the engine control

board
Waste
Cartridge
Full

The waste cartridge is full. The engine
control board detected that the waste
cartridge sensor was on for 1250 print
cycles.

1. Replace the waste cartridge
2. Test the waste cartridge full

Replace
Black Toner
Cartridge

Black image density is too low. The
engine control board detected that the
auto-density calibration sensor reads
the black patch density as being below
specification and that the reading is
either slow to raise or does not raise
after the printer attempts to increase
density.

1. Replace the black toner

26

Phaser 780 Color Printer

sensor using internal
diagnostics
3. Inspect the electrical
contacts and wiring Replace
the waste cartridge full
sensor
4. Replace the engine control
board
cartridge
2. Test the toner/developer

dispense motor
3. Test the auto-density

calibration sensor
4. Replace the engine control

board

Error code
and
message

Description

Corrective action

Replace
Cyan Toner
Cartridge

Cyan image density is too low. The
engine control board detected that the
auto-density calibration sensor reads
the cyan patch density as being below
specification and that the reading is
either slow to raise or does not raise
after the printer attempts to increase
density.

1. Replace the cyan toner

Magenta image density is too low. The
engine control board detected that the
auto-density calibration sensor reads
the magenta patch density as being
below specification and that the reading
is either slow to raise or does not raise
after the printer attempts to increase
density.

1. Replace the magenta toner

Yellow image density is too low. The
engine control board detected that the
auto-density calibration sensor reads
the yellow patch density as being below
specification and that the reading is
either slow to raise or does not raise
after the printer attempts to increase
density.

1. Replace the yellow toner

The imaging unit has reached end of life.
The engine control board detected that
the installed imaging unit has reached
end of life.

1. Replace the imaging unit
2. Switch the printer power off,

The fuser oil roll is nearing end of life.
The engine control board detected that
the fuser oil roll is nearing the 20,000
mark.

1. Replace the fuser oil roll
2. Replace the engine control

Replace
Magenta
Toner
Cartridge

Replace
Yellow Toner
Cartridge

Replace
Imaging Unit

Fuser Roll
Cartridge
Low

cartridge
2. Test the toner/developer

dispense motor
3. Test the auto-density

calibration sensor
4. Replace the engine control

board

cartridge
2. Test the toner/developer

dispense motor
3. Test the e auto-density

calibration sensor
4. Replace the engine control

board

cartridge
2. Test the toner/developer

dispense motor
3. Test the auto-density

calibration sensor
4. Replace the engine control

board

then on
3. Inspect the CRUM for

damage or contamination.
clean or replace if necessary.
4. Replace the engine control
board

board

Service Guide

27

Error code
and
message

Description

Corrective action

Waste
Cartridge
Almost Full

The waste toner box is almost full. The
engine control board detected that the
waste toner box is almost full and will
soon need to be replaced.

1. Replace the waste toner box
2. Replace the engine control

Black Toner
Low

The black toner cartridge is low on toner.
The engine control board switched on
the dispense motor for more than 980
seconds in order to raise the image
density to normal.

1. Replace the black toner

The cyan toner cartridge is low on toner.
The engine control board switched on
the Dispense Motor for more than 800
seconds in order to raise the image
density to normal.

1. Replace the cyan toner

The magenta toner cartridge is low on
toner. The engine control board switched
on the Dispense Motor for more than
800 seconds in order to raise the image
density to normal.

1. Replace the magenta toner

The yellow toner cartridge is low on
toner. the engine control board switched
on the Dispense Motor for more than
1150 seconds in order to raise the
image density to normal.

1. Replace the yellow toner

Cyan Toner
Low

Magenta
Toner Low

Yellow Toner
Low

28

Phaser 780 Color Printer

board

cartridge
2. Test the dispense motor
3. Test the auto-density

calibration. Replace it, if
necessary.
4. Replace the engine control
board
cartridge
2. Test the dispense motor
3. Test the auto-density

calibration. Replace it, if
necessary.
4. Replace the engine control
board
cartridge
2. Test the dispense motor
3. Test the auto-density

calibration. Replace it, if
necessary.
4. Replace the engine control
board
cartridge
2. Test the dispense motor
3. Test the auto-density

calibration. Replace it, if
necessary.
4. Replace the engine control
board

Error code
and
message

Description

Corrective action

Media Low in
Tray 4

The engine control board detected that
the tray 4 low paper sensor is actuated.

1. Add paper to tray 4
2. Check for a damaged or

missing sensor actuator.
3. Replace the tray 4 low sensor
4. Replace the engine control

board
Media Low in
Tray 3

The engine control board detected that
the tray 3 low paper sensor is actuated.

1. Add paper to tray 3
2. Check for a damaged or

missing sensor actuator.
3. Replace the tray 3 low sensor
4. Replace the engine control

board
Media Low in
Tray 2

The engine control board detected that
the tray 2 low paper sensor is actuated.

1. Add paper to tray 2
2. Check for a damaged or

missing sensor actuator.
3. Replace the tray 2 low sensor
4. Replace the engine control

board
Media Low in
Tray 1

The engine control board detected that
the Tray 1 Low Paper Sensor is
actuated.

1. Add paper to tray 1
2. Check for a damaged or

missing sensor actuator.
3. Replace the tray 1 low sensor
4. Replace the engine control

board
Load Media
in Multipurpose Tray

The multi-purpose tray is out of paper.
The engine control board detected that
the long multi-purpose tray paper sensor
is not actuated.

1. Load paper into the

multi-purpose tray
2. Test the multi-purpose tray

paper sensors
3. Replace the engine control

board
Load Media
in Tray 4

Tray 4 is out of paper.
The engine control board detected that
the paper empty sensor in tray 4 is
actuated.

1. Load paper into Tray 4
2. Test the paper empty sensor
3. Replace the lower feeder

circuit board
4. Replace the lower feeder

assembly
5. Replace the engine control

board

Service Guide

29

Error code
and
message

Description

Corrective action

Load Media
in Tray 3

Tray 3 is out of paper. The engine control
board detected that the paper empty
sensor in tray 3 is actuated.

1. Load paper into Tray 3
2. Test the tray’s paper empty

sensor
3. Replace the lower feeder

circuit board
4. Replace the lower feeder

assembly
5. Replace the engine control

board
Load Media
in Tray 2

Tray 2 is out of paper. The engine control
board detected that the paper empty
sensor in tray 2 is actuated.

1. Load paper into Tray 2
2. Test the tray’s paper empty

sensor
3. Replace the lower feeder

circuit board
4. Replace the lower feeder

assembly
5. Replace the engine control

board
Load Media
in Tray 1

Tray 1 is out of paper. The engine control
board detected that the paper empty
sensor in tray 1 is actuated.

1. Load paper into Tray 1
2. Test the tray’s paper empty

sensor
3. Replace the lower feeder

circuit board
4. Replace the engine control

board
Clear Jam At
A, B

The engine control board detected that
the registration sensor was actuated
while the printer was in standby.

1. Clear jammed paper from the

printer
2. Test the feeder registration

exit sensor
3. Replace the engine control

board

30

Phaser 780 Color Printer

Error code
and
message

Description

Corrective action

Clear Jam At
A, B

There is a problem near the registration
sensor. The engine control board
detected that the registration sensor did
not actuate within the specified time
after paper feed.

1. Clear jammed paper from the

There is problem at the fuser exit
sensor. The engine control board
detected that the fuser exit sensor was
actuated while the printer was in
standby.

1. Clear jammed paper from the

There is problem near the fuser exit
sensor. The engine control board
detected that the fuser exit sensor did
not actuate within the specified time
after the fuser entrance sensor was
actuated.

1. Clear jammed paper from the

There is problem at the media exit
sensor. The engine control board
detected that the top exit sensor was
actuated while the printer was in
standby.

1. Clear jammed paper from the

Clear Jam At
C, D

Clear Jam At
C, D

Clear Jam at
E

printer
2. Check that the media tray

and ensure it is correctly
loaded
3. Test the pre-registration
clutch
4. Test the registration clutch
5. Test the paper feed motor
6. Check the operation of the
paper pick solenoid
7. Inspect the paper path
8. Clean the feed rollers
9. Test the registration sensor
10. Run the paper path test
11. Replace the engine control
board
printer
2. Test the fuser exit sensor
3. Replace the engine control

board

printer
Test the fuser exit sensor
Inspect the paper path
Inspect the fuser chute fan
Replace the fuser
Inspect the fuser drive gear
train. Replace if necessary
7. Replace the paper feed
motor.
8. Replace the engine control
board
2.
3.
4.
5.
6.

printer
2. Test the feeder media exit

sensor
3. Inspect the paper exit path
4. Replace the engine control

board

Service Guide

31

Error code
and
message

Description

Corrective action

Clear Jam At
E

The engine control board detected that
the media exit sensor did not actuate
within the specified time after the fuser
exit sensor actuated.

1. Clear jammed paper from the

printer
2. Inspect and clean the exit

rollers
3. Test the media exit sensor
4. Inspect and test the paper

feed gear train and paper
motor
5. Test the fuser drive gear train
and exit guide
6. Replace the engine control
board
Media Size
Mismatch

The engine control board detected that
the paper that was fed into the printer
was not the same size that was detected
by the tray size sensors. The registration
sensor monitors the timing of the paper
as it runs through the printer.

1. Set paper tray guides or use

another paper tray
2. Inspect the actuators at the

rear of the paper tray.
3. Test the paper tray size

sensors
4. Replace the paper tray size

sensor board.
5. Replace the engine control

board
Install Black
Toner
Cartridge

The black toner cartridge is either not
installed or not installed correctly. The
engine control board did not receive a
signal from the cartridge sensor when
the carousel frame moved the black
developer housing into position.

1. Reseat the black toner

Install Cyan
Toner
Cartridge

The cyan toner cartridge is either not
installed or not installed correctly. The
engine control board did not receive a
signal from the cartridge sensor when
the carousel frame moved the cyan
developer housing into position.

1. Reseat the cyan toner

32

Phaser 780 Color Printer

cartridge. Power cycle the
printer
2. Replace the black toner
cartridge
3. Replace the toner cartridge
presence sensor.
4. Replace the engine control
board.
cartridge. Power cycle the
printer
2. Replace the cyan toner
cartridge
3. Replace the toner cartridge
presence sensor.

Error code
and
message

Description

Corrective action

Install
Magenta
Toner
Cartridge

The magenta toner cartridge is either
not installed or not installed correctly.
The engine control board did not receive
a signal from the cartridge sensor when
the carousel frame moved the magenta
developer housing into position.

1. Reseat the magenta toner

Install Yellow
Toner
Cartridge

The yellow toner cartridge is either not
installed or not installed correctly. The
engine control board did not receive a
signal from the cartridge sensor when
the carousel frame moved the yellow
developer housing into position.

1. Reseat the yellow toner

Install Waste
Cartridge

The waste toner box is not installed. The
engine control board detected that the
waste toner box sensor was deactuated.

1.
2.
3.
4.
5.
6.

Install
Tray 1

The engine control board did not detect
a paper tray installed in Tray 1 slot.

1. Reseat the tray into the main

cartridge. Power cycle the
printer
2. Replace the magenta toner
cartridge
3. Replace the toner cartridge
presence sensor.
cartridge. Power cycle the
printer
2. Replace the yellow toner
cartridge
3. Replace the toner cartridge
presence sensor.
4. Replace the engine control
board.
Reseat waste cartridge
Power cycle the printer
Test the waste toner sensor
Check the sensor wiring
Replace the sensor
Replace the engine control
board
feeder slot
2. Inspect the tray’s switch

actuators for damage
3. Replace the paper size

sensor assembly
4. Replace the engine control

board
Install
Tray 2

The engine control board did not detect
a Paper Tray installed in Tray 2 slot.

1. Reseat the tray into the

second feeder slot
2. Inspect the tray’s switch

actuators for damage
3. Replace the paper size

sensor assembly
4. Inspect the lower

feeder-to-printer connections
at the back of the printer.
5. Replace the engine control
board
Service Guide

33

Error code
and
message

Description

Corrective action

Install
Tray 3

The engine control board did not detect
a Paper Tray installed in Tray 3 slot.

1. Reseat the tray into the third

feeder slot
2. Inspect the tray’s switch

actuators for damage
3. Inspect the lower

feeder-to-printer connections
Replace the paper size
sensor assembly
4. Replace the engine control
board
Install
Tray 4

The engine control board did not detect
a Paper Tray installed in Tray 4 slot.

1. Reseat the tray into the fourth

feeder slot
2. Inspect the tray’s switch

actuators for damage
3. Inspect the lower

feeder-to-printer connections
Replace the paper size
sensor assembly
4. Replace the engine control
board
Install
Imaging Unit

Install Fuser
Roll
Cartridge

34

The imaging unit is either not installed or
not installed correctly. The engine
control board did receive a signal from
the customer replaceable unit memory.

1. Reseat the imaging unit
2. Inspect the CRUM connector

The engine control board detected that
the fuser oil roll assembly circuit is open.

1. Reseat the fuser oil roll
2. Inspect the fuser roll contacts

for damage or contamination.
Clean or replace if necessary
3. Replace the imaging unit
4. Replace the engine control
board

and connectors. Ensure they
are clean and seated
correctly
3. Replace the fuser roll
4. Replace the engine control
board

Phaser 780 Color Printer

Error code
and
message

Description

Corrective action

Second Bias
Transfer
Roller Error

The engine control board detected that
the measured current value across
second bias transfer roller was not within
specifications.

1. Power cycle the printer
2. Replace the high voltage

power supply
3. Replace the engine control

board
4. Replace the second bias

transfer roller
5. Replace the accumulator belt

assembly
Replace
Fuser

The fuser has reached end of life. The
engine control board detected that the
fuser has processed 250,000 images or
the toner dispense motor has
accumulated more than 70,564 x 100ms
of running time.

1. Use diagnostics to verify the

Printer
Maintenance
Required Replace the
Accumulator
Belt Cleaner

The accumulator belt cleaner is nearing
end of life. The engine control board
detected that the accumulator belt
cleaner processed 100,000 sheets of
paper.

1. Use diagnostics to verify the

Printer
Maintenance
Required

The accumulator cleaner belt has
reached end of life. The engine control
board detected that the accumulator belt
cleaner has processed over 102,000
belt clean cycles.

1. Use diagnostics to verify the

The second bias transfer roller is
nearing the end of its life. The engine
control board detected that the second
bias transfer roller has processed
100,000 sheets of paper.

1. Use diagnostics to verify the

Printer
Maintenance
Required Replace the
Second Bias
Transfer
Roller

print count
2. Replace the fuser
3. Replace the engine control

board

print count
2. Replace the accumulator belt

cleaner
3. Replace the engine control

board

print count
2. Replace the accumulator belt

cleaner
3. Replace the engine control

board
print count
2. Replace the second bias

transfer roller
3. Replace the engine control

board

Service Guide

35

Error code
and
message

Description

Corrective action

Printer
Maintenance
Required

The second bias transfer roller has
reached end of life. The engine control
board detected that second bias transfer
roller has completed over 100,000
images.

1. Use diagnostics to verify the

Printer
Maintenance
Required
Soon Imaging Unit
Life Almost
Over

The imaging unit has reached end of life.
The engine control board detected that
the drum inside the imaging unit has
exceeded 90,000 revolutions.

1. Replace the imaging unit
2. Replace the engine control

Fuser Life
Almost Over

The fuser is nearing end of life. The
engine control board detected that the
fuser processed 237,500 images or the
toner dispense motor has accumulated
more than 67,036 x 100ms of running
time.

1. Replace the fuser
2. Replace the engine control

The imaging unit has reached end of life.
The engine control board detected that
the imaging unit has printed 110,000
images.

1. Replace the imaging unit
2. Check the CRUM connector

The engine control board detected that
the lower feeder cover interlock switch is
deactuated.

1. Close the feeder cover
2. Inspect the interlock switch.

Replace the
imaging unit

Close Lower
Tray
Assembly
Cover

print count
2. Replace the second bias

transfer roller
3. Replace the engine control

board

board

board

for damage or contamination.
Clean or replace if necessary
3. Replace the engine control
board

Replace if necessary
3. Replace the feeder control

board
4. Inspect the lower

feeder-to-printer connections
at the rear of the printer
5. Replace the feeder
6. Replace the engine control
board

36

Phaser 780 Color Printer

Error code
and
message

Description

Corrective action

Close Left
Fuser Unit

The engine control board detected that
the fuser interlock circuit is open.

1. Reseat the fuser
2. Inspect the fuser mating

connectors for proper fit
3. Replace the engine control

board
Close Exit
Cover

The engine control board detected that
the exit door switch is deactuated.

1. Close the exit cover
2. Replace the exit chute switch
3. Replace the upper exit

assembly
4. Replace the engine control

board
Close Right
Feed Unit

Close Front
Cover

The engine control board detected that
the paper feeder Interlock circuit is
open.

1. Close the paper feeder

The engine control board detected that
the front cover interlock switch is
deactuated.

1. Close the front cover
2. Inspect the cover’s switch

assembly
2. Inspect the mating

connectors of the paper
feeder
3. Replace the paper feed
harness
4. Replace the paper feeder
5. Replace the engine control
board

actuators. Replace the cover
if damaged
3. Test for +24 VDC at Pins
P32-8 and 3. You should
measure 24 VDC at pin 3
through the right and left
cover interlock switches back
to pin 8.
4. Test for 5 VDC between
P33-1 and frame ground It
should switch between 5
and 0 VDC when the front
cover is opened and closed.
If not replace the left front
cover switch
5. Replace the low voltage
power supply

Service Guide

37

Error code
and
message

Description

Corrective action

Empty the
Top Output
Tray

The engine control board detected that
the full stack sensor is actuated for more
than 12 seconds.

1. Remove the prints from

output tray
2. Inspect for damage the

output tray full sensor.
Replace if necessary
3. Replace the engine control
board

Troubleshooting
System power-up sequence
1. The main power switch is turned on. (Or the front cover is opened and
then closed or diagnostics are exited.)

2. The print engine reads the Customer Replaceable Unit Memory (CRUM).
3. The print engine determines that all the CRUs are in place, except for the
toner cartridges.

4. The print engine checks its sensors for any static jam errors.
5. The print engine reads all life counters in NVRAM.
6. The print engine applies voltage to the fuser to bring it up to standby
temperature.

7. The process motor energizes and then a 1/4 second later, the paper feed
motor is energized.

8. The print engine powers on the carousel motor and checks the presence of
the four toner developer assemblies.

9. The print engine verifies proper operation of the image process
components. The auto-density calibration sensor checks the density
levels.

10. The print engine initiates a cleaning cycle of the accumulator belt.
11. The process motor is de-energized.
12. The print engine updates the NVRAM
13. The print engine updates the CRU memory.
14. The paper feed motor is de-energized.
The print engine is initialized.

Service Guide

39

Print engine troubleshooting
Printer will not power up
When you switch on the printer, the control panel does not light, the fans do not
rotate, the carousel motor does not cycle, and the printer does not go into warmup.

1. 110VAC IN Check
a.

Inspect the AC Power Cord. Is the AC Power Cord plugged into the
printer, and is the other end plugged into an AC wall outlet?

b.

Check the voltage at the AC wall outlet. Is there approximately
110 VAC (or 220 VAC if the printer is the 220 VAC model) at the AC
wall outlet?

c.

Remove the rear cover.

d.

Measure the voltage between the two low voltage power supply
solder points located next to the AC power jack. Is there 110 VAC
between the two points?

2. Low voltage power supply check
a.

Measure the voltage between P33-3 on the low voltage power
supply and frame ground. Is there +5 VDC between P33-3 and
frame ground. If not, replace the low voltage power supply.

a.

Check for +24VDC between P32-3 on the low voltage power supply
and frame ground. Replace the low voltage power supply. Check
for +24VDC between P32-8 and frame ground. If voltage is at pin 3
but not at pin 8, check the front cover, fuser and paper feeder
interlock switches. Is there +24VDC between P32-11 and frame
ground? If not, replace the power supply. Check for a short in the
24 volt components (particularly on the paper feed motor circuit
board).

3. Low voltage power supply loading check
a.

Disconnect P32 and P33 from the low voltage power supply.

b.

Measure the voltage between P33-3 on the low voltage power
supply and frame ground, and between P32-11 on the low voltage
power supply and frame ground. Is there +5 VDC between P33-3
and frame ground, and is there +24 VDC between P32-11 and frame
ground? If not, replace the low voltage power supply.

4. Engine control board loading check

40

a.

Reconnect P32 and P33 to the low voltage power supply.

b.

Refer to “Wiring Diagrams” on page 185 and one by one disconnect
components that are connected to the engine control board.

Phaser 780 Color Printer

c.

Measure the voltage between P33-3 on the low voltage power
supply and frame ground, and between P32-11 on the low voltage
power supply and frame ground. Do you eventually measure
+5 VDC between P33-3 and frame ground, and +24 VDC between
P32-11 and frame ground? If yes, replace the component that is
loading down the power supply. If no, replace the engine control
board.

5. Image processor check
a.

Turn off the printer.

b.

Remove the image processor board.

c.

Turn on the printer. Does the printer go into warm-up? If yes,
replace the image processor board. If not, replace the engine
control board.

Erratic printer operation
The printer has a variety of intermittent problems, but generally does not
complete a print cycle. The problems are generally not identified by
displayed error codes.
1. Does the printer frequently fail to enter printer warm-up or is the front
panel frequently inoperative? If yes, follow the earlier procedure
“Printer will not power up” on page 40.

2. Run print engine test prints, which print independently of the image
processor, to determine if the image processor is the problem. Refer to
“Making a print engine only test print” on page 42.

3. Low voltage power supply loading check
a.

Run 50 test prints from the image processor’s built in test prints.

b.

Measure the voltage between P33-3 on the low voltage power
supply and frame ground, and between P32-11 on the low voltage
power supply and frame ground. Is there a steady +5 VDC
between P33-3 and frame ground, and is there at steady +24V DC
between P32-11 and frame ground? If no, Replace the low voltage
power supply.

4. If test prints from the image processor print reliably, reload the host’s
printer driver software or the host application software. Does the printer
still exhibit erratic operation?

5. Try printer from another application. Ensure that the host computer
prints reliable to a different printer. Also try printing from another
computer to the Phaser 780.

6. Replace the interface cable connecting the host to the printer.
7. Replace the engine control board.
8. Replace the image processor board.

Service Guide

41

Making a print engine only test print
Using the image processor.
1. Turn off the printer.
2. Remove the right side panel to access the image processor board.
3. Locate switch 4 of S930 on the image processor board. Closing switch 4
bypasses the image processor board and places the engine control board
into test mode upon power up.

4. Turn on the printer.
5. The printer generates process black (all four colors layered) grid patterns.
The printer feeds from the first tray that has paper - in this order; Tray 1,
Tray 2, Tray 3, Tray 4, and multi-purpose feeder. The printer sends the test
prints to the face down output tray. The printer generates test prints until
you stop the test.

6. Switch off printer main power to stop generating test prints.
7. Move the S930 switch 4 to the off (open) position.
Using the print engine board. To generate a test print without the image processor
installed.

1. Turn off the printer.
2. Remove the image processor so you can access the engine control board.
3. Locate JP3, just below the ROM chip on the engine control board.
4. Move the switch to the ON position.
5. Turn on the printer.
6. The printer generates test prints just as it does in the previous procedure.
7. Switch off printer main power to stop generating test prints.
8. Move the switch to the 1 position.

42

Phaser 780 Color Printer

Printing and print quality problems
Initial checks and actions
1. Does the printer display an error code? If so go to “Error Codes and
Messages” on page 19.

2. Is the AC power provided at the wall outlet within recommended
specifications?

3. Is the printer properly gounded through the AC wall outlet?
4. Is the printer located in an area where the temperature and humidity are
stable and within specifications?

5. Is the printer located in an area free of dust?
6. Is the printer located away from water outlets, steamers, electric heaters,
volatile gases, open flames and strong radio frequency sources?

7. Is the printer shielded from the direct rays of the sun?
8. Does the printer have adequate clearances on all sides for proper
ventilations?

9. Is the printer installed on a level, stable surface?
10. Is the correct paper stock being used in the printer?
11. Is the customer using the printer correctly as explained in the user
documentation?

12. Have the consumables been replaced correctly at the required intervals?
13. Is the problem a failure or the result of improper use, incorrect media
type/weight, excessive use or a limitation of the duty cycle?

Service Guide

43

Light (undertone) prints
The overall image density is too light.
The printer displays no error code.

1. Inspect the paper that is
loaded in the paper tray.
Check that the paper is not
wrinkled or moist. Also
ensure it is the correct weight.
Card stock must be feed from
the multi-purpose tray.
Recycled paper and paper
less than 24 lbs may produce
less than optimum quality.

2. Clean and inspect the auto-

3041-37

density calibration sensor. Test
the sensor using the printer’s
built-in diagnostics. If an error
11, 12, or 13 is detected, replace
the auto-density calibration
sensor.

3. Print Service Test Print 1 on Bsize paper and open the front cover just as the sheet of paper starts to exit
the fuser. Inspect the image on the sheet of paper before it reaches the fuser
rollers. Is the image density normal before it reached the fuser rollers? If no,
go to Step 4. If yes, go to Step 7.
4. Remove the imaging unit.
5. Inspect the test print image on the accumulator belt. Does the image
appear completely transferred to the accumulator belt? If yes, replace the
second bias transfer roller. If not, replace the accumulator belt.

6. Print Service Test Print 1 and inspect the image on the sheet of paper. Is
the image density now normal? If not, replace the high voltage power
supply.

7. Print Service Test Print 1 again and inspect the image on the sheet of paper
after it exits the fuser rolls. Is the image light when it exits the fuser? If
yes, replace the oil roll cartridge.

8. Generate a test print.
9. Inspect the image on the sheet. Is the image density now normal as it exits
the fuser? If not, replace the fuser.

44

Phaser 780 Color Printer

Blank prints
The entire image area is blank. The
printer displays no error code.

1. Generate a test print. Is the
test print blank? If no, reload
the printer driver software or
replace the image processor
board.

2. Remove the imaging unit.
3. Inspect the empty imaging
unit cavity for a sheet of paper
that could be blocking the
laser window.

4. Generate a test print and open
the front cover just before the
sheet of paper enters the fuser.

5. Remove the imaging unit.
6.

Inspect the image on the
drum. Is there an image visible on
the drum? If not, make an engine-only test print. If a test print is printed,
replace the image processor board. If not, replace the imaging unit.

7. Generate a test print. Is the test print blank? If yes, replace the high
voltage power supply.

8. Inspect the image on the surface of the accumulator belt? Is there an
image visible on the surface of the accumulator belt? If yes, replace the
second bias transfer roller. If not replace the accumulator belt.

9. Replace the engine control board.

Service Guide

45

Monochrome prints

3041-38

No color is present in a color print, only the black layer is printed. The printer
displays no error code. In some cases, depending on the nature of the failure,
only a portion of the print may be monochrome while the remainder of the print
is in color.

1. Check the accumulator belt cleaner for correct installation. The cleaning
blade may be in constant contact with the accumulator belt, scraping off
each layer of color toner soon after it is transferred.

2. Inspect the cleaner cam guides and holders located at the front and back of
the fuser assembly. Are the cleaner cam holders seated properly? If not,
reseat them as necessary.

3. Manually actuate the cleaner cam solenoid and rotate the fuser input gear
to cycle the cleaner cam through its cycle of operation. Does the cleaner
cam operate the cleaner cam guides properly? If not, replace the fuser
assembly.

4. Replace the accumulator belt cleaner.

46

Phaser 780 Color Printer

Black prints
The entire image area is black. The
printer displays no error code.

1. Power cycle the printer, if an
error 10 is detected replace
the laser scanner unit.

2. Replace the engine control
board.

3. Print Service Test Print 1.
4. Is the test print completely
black? If no, reload the
printer driver software or
replace the image processor
board.

5. Generate a test print and open
the front door just before the
sheet of paper enters the fuser.

6. Remove the imaging unit.
7. Inspect the image on the
drum. Is there a developed test print image visible on the drum? If no,
replace the imaging unit.
8. Generate a test print. Is the test print black? Replace the high voltage
power supply.

One color is faded

3041-39

Toner cartridge is depleted or the toner developer is defective.

1. Replace the defective toner cartridge.
2. Replace the toner developer of the defective color.

Service Guide

47

Missing band in direction of paper travel
There are areas of the image that are
extremely light or are missing
entirely. These missing areas form
wide bands that run along the page
from leading edge to trailing edge in
the direction of paper travel (B-size
print shown). The printer displays no
error code.

Leading Edge

Note

3041-40

A-size prints are processed
through the printer with the
short edge of the print parallel to
the direction of the paper path
making print artifacts parallel to
the short edge of the print.
In B-size prints are processed
through the printer with the long
edge of the print parallel to the
paper path making artifacts
parallel to the long axis of the
print.

1. Is the paper wrinkled, dimpled, or show any signs of having a high
moisture content? Load fresh, dry paper.

2. Print Service Print 1. Do the bands appear in all four colors, If yes, go to
Step 3, If not, go to Step 7.

3. Remove the imaging unit. Inspect the empty cavity for a scrap of paper or
a toner blotch that could be blocking the laser window.

4. Generate a test print and open the front cover just before the sheet of
paper enters the fuser.

5. Remove the imaging unit.
6. Inspect the image on the drum. Is there a normal test print image, without
any vertical band deletions, visible on the drum? If yes, go to Step 9. If no,
go to Step 7.

7. Remove the top cover.
8. Turn the carousel frame and inspect the magnetic rollers of each of the
four developer assemblies. Do the magnetic rollers of each developer
assembly appear smooth, evenly formed, without any low spots, and
without obvious contamination? If yes, replace the imaging unit. If not,
replace the faulty developer assembly.

9. Inspect the image on the surface of the accumulator belt? Is there a
normal test image, without any band deletions, visible on the surface of
the accumulator belt? If no, replace the accumulator belt.

10. Generate a test print and open the front cover just before the sheet of
paper enters the fuser.

48

Phaser 780 Color Printer

11. Inspect the image on the paper just before the paper enter the fuser. Is
there a normal test print image, without any band deletions, visible on the
sheet of paper? If not, replace the second bias transfer roller.

12. Generate a test print and slide the fuser assembly out of the printer just as
the sheet of paper exits the fuser.

13. Inspect the image on the sheet of paper just after the paper exits the fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has visible band deletions after it exits the fuser? If
yes, replace the oil roll cartridge.

14. Generate a test print.
15. Inspect the image on the sheet. Is the image now normal, without band
deletions as it exits the fuser? If no, replace the fuser.

Missing bands in parallel to the leading edge
There are areas of the image that are
extremely light or are missing
entirely. These missing areas form
wide bands that run across the page
parallel with the leading edge of the
print, perpendicular with the
direction of paper travel (B-size print
shown). The printer displays no error
code.

Leading Edge

Note A-size prints are processed
through the printer with the short
edge of the print parallel to the
direction of the paper path making
print artifacts parallel to the long
edge of the print.

3041-41

In B-size prints are processed
through the printer with the long
edge of the print parallel to the
paper path making artifacts
parallel to the short axis of the
print.

1. Inspect the paper that is loaded in the paper tray. Is the paper wrinkled,
dimpled, or show any signs of having a high moisture content?

2. Print Service Print 1. Do the bands appear in all four colors, If yes, go to
Step 3, If not, go to Step 11.

3. Generate a test print and open the front cover just before the sheet of
paper enters the fuser.

4. Remove the imaging unit.

Service Guide

49

5. Inspect the image on the drum. Is there a normal test print image, without
any band deletions, visible on the drum? If yes, go to Step 6. If not,
replace the imaging unit.

6. Inspect the image on the surface of the accumulator belt? Is there a
normal test print image, without any horizontal band deletions, visible on
the surface of the accumulator belt? If no, replace the accumulator belt.

7. Inspect the image on the sheet of paper just before the paper enter the
fuser. Is there a normal test print image, without any band deletions,
visible on the sheet of paper? If not, replace the second bias transfer roller.

8. Generate a test print and open the front cover just as the sheet of paper
exits the fuser.

9. Inspect the image on the sheet of paper just after the paper exits the fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has visible horizontal band deletions after it exits the
fuser? If yes, replace the fuser roll cartridge.

10. Make another test print. If the problem still occurs, replace the fuser.
11. Remove the top cover.
12. Turn the carousel frame and inspect the magnet roller of each of the four
developer assemblies. Do the magnet rollers of each developer assembly
appear smooth, evenly formed, without any low spots, and without
obvious contamination? If not, replace the defective developer assembly.

13. Replace the high voltage power supply.
14. Replace each of the four developer assemblies, one at a time.

50

Phaser 780 Color Printer

Streaks in direction of paper travel
There are dark lines running along
the page in the direction of paper
travel from the leading edge to the
trailing edge (B-size print shown).
The printer displays no error code.

Leading Edge

Note A-size prints are processed
through the printer with the
short edge of the print parallel to
the direction of the paper path
making horizontal print artifacts
parallel to the shot edge of the
print.
In B-size prints are processed
through the printer with the long
edge of the print parallel to the
paper path making horizontal
artifacts parallel to the long axis
of the print.
3041-42

1. Inspect the paper path, between feed and exit, for contamination or
obstructions. Is the paper path free of contamination or obstructions?

2. Check for dirty fuser guide rollers. Also look for toner contamination on
the fuser’s temperature sensor.

3. Print Service Print 4 and open the front cover just before the sheet of
paper enters the fuser.

4. Remove the imaging unit.
5. Inspect the image on the drum. Is there a normal test print image,
without any streaks, visible on the drum? If yes, go to Step 6. If not,
replace the imaging unit.

6. Inspect the image on the surface of the accumulator belt. Is there a
normal test print image, without any streaks, visible on the surface of the
accumulator belt? If no, replace the accumulator belt. If yes, inspect the
accumulator belt cleaner’s plastic shield for damage; replace the belt
cleaner, if necessary. Replace the second bias transfer roller.

7. Generate a test print and open the front cover just as the sheet of paper
exits the fuser.

8. Inspect the image on the sheet of paper just after the paper exits the fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has visible streaks after it exits the fuser? If yes,
replace the fuser roll cartridge. If streaks continue to occur, replace the
fuser.

9. Remove the top cover.
Service Guide

51

10. Turn the carousel frame and inspect the magnet roller of each of the four
developer assemblies. Do the magnet rollers of each developer assembly
appear smooth, evenly formed, without any low spots, and without
obvious contamination? If not, replace the defective developer assembly.

11. Replace the high voltage power supply.

Streaks parallel with the leading edge
There are dark lines running parallel
with the leading edge of the print,
perpendicular to direction of paper
travel (B-size print shown). The
printer displays no error code.

Leading Edge

Note

A-size prints are processed
through the printer with the
short edge of the print parallel to
the direction of the paper path
making print artifacts parallel to
the long edge of the print.
In B-size prints are processed
through the printer with the long
edge of the print parallel to the
paper path making artifacts
parallel to the short axis of the
print.

3041-43

1.Print Service Print 1. Do the
streaks appear in all colors? If not, go to Step 8.
2. Print Service Print 4 and open the front cover just before the sheet of paper
enters the fuser.

3. Remove the imaging unit.
4. Inspect the image on the drum. Is there a normal test print image, without
any horizontal streaks, visible on the drum? If yes, go to Step 4. If not,
replace the imaging unit.

5. Inspect the image on the surface of the accumulator belt. Is there a normal
test print image, without any streaks, visible on the surface of the
accumulator belt? If no, replace the accumulator belt. If yes, inspect the
accumulator belt cleaner’s plastic shield for damage; replace the belt
cleaner, if necessary. Replace the second bias transfer roller.

6. Print Service Print 4 and slide the fuser out of the printer just as the sheet
of paper exits the fuser.

7. Inspect the image on the sheet of paper just after the paper exits the fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has visible streaks after it exits the fuser? If yes,
replace the fuser roll cartridge. If streaks continue to occur, replace the
fuser.

52

Phaser 780 Color Printer

8. Remove the top cover. Turn the carousel frame and inspect the magnet
roller of each of the four developer assemblies. Do the magnet rollers of
each developer assembly appear smooth, evenly formed, without any low
spots, and without obvious contamination? If not, replace the defective
developer assembly.

9. Replace the high voltage power supply.

Banding

3041-44

There are three kinds of banding:

1. If a dark band appears every 364 mm from the leading edge of a B-size
print or occasionally on A-size print, reseat the imaging unit and print
again. If the problem persists perform the procedure “Adjusting for
impulse banding” on page 74.

2. If a dark band appears at a 1.3 to 1.7 mm pitch throughout solid fills,
replace the process drive assembly.

3. Dark bands appearing randomly in solid fills at pitches such as 44 mm, 88
mm or 104 mm. Replace the process drive assembly.

Edge of print is wrinkled with an area of ragged discoloration.

3041-45

The fuser roll cartridge is out of position.

1. Reseat the fuser roll cartridge

Service Guide

53

Random missing spots
There are small areas of the image
that are extremely light or are missing
entirely. These missing areas form
spots that are localized to small areas
of the page. The printer displays no
error code. A small number of
occasional missing spots is normal.

1. Inspect the paper that is
loaded in the paper tray.
Ensure the paper is not
wrinkled nor moist?

2. Random white spots with a

3041-46

small grit-like center, usually
occurring in cyan and
magenta, can be caused by
compacted toner. Print
Service Print 5, 6, 7, or 8,
which ever color applies, to
purge out the toner of the
affective color.

3. Replace the affected toner cartridge. If problem continues replace that
color’s developer.

4. Generate a test print and open the front cover just before the sheet of
paper enters the fuser.

5. Remove the imaging unit. Inspect the image on the drum. Is there a
normal test print image, without any spot deletions, visible on the drum?
If yes, go to Step 6. If not, replace the imaging unit.

6. Inspect the image on the surface of the accumulator belt? Is there a
normal test print image, without any spot deletions, visible on the surface
of the accumulator belt? If no, replace the accumulator belt.

7. Inspect the image on the sheet of paper just before the paper enter the
fuser. Is there a normal test print image, without any spot deletions? If
no, replace the second bias transfer roller.

8. Print Service Print 2 and open the front cover just as the sheet of paper
exits the fuser.

9. Inspect the image on the sheet of paper just after the paper exits the Fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has visible spot deletions after it exits the fuser? If yes,
replace the fuser roll cartridge.

10. Make another test print. If the problem still occurs, replace the fuser.
11. Make a test print and the remove the top cover.
12. Turn the carousel frame and inspect the magnet roller of each of the four
developer assemblies. Do the magnet rollers of each developer assembly
appear smooth, evenly formed, without any low spots, and without
obvious contamination? If not, replace the defective developer assembly.

54

Phaser 780 Color Printer

Random spotting

3041-47

There are spots of toner randomly scattered across the page. The printer displays
no error code.

1. Slide the paper feeder out of the printer and inspect the top of the
registration chute assembly. Is the top of the registration chute assembly
free of toner and foreign debris? If not, remove and inspect the waste
toner cartridge. Make sure the cartridge is not damaged or leaking.

2. If the spots appear in a single color, run 20 prints to consume the clumped
toner. If necessary, replace the toner cartridge.

3. Remove and inspect the imaging unit. Is the exterior of the imaging unit
clean and with no obvious toner leakage? If not, remove and inspect the
waste toner cartridge. Make sure the cartridge is not damaged or leaking.

4. Remove the top cover.
5. Turn the carousel frame and inspect the four developer assemblies. Does
each developer assembly appear clean, without any obvious toner on the
exterior of the assembly or falling from the magnetic brush? Clean the
dirty developer assembly. If the problem reoccurs, replace the faulty
developer assembly.

6. Inspect the fuser. Is the fuser free of toner? Clean the fuser, if necessary
by processing 10 sheets of B-size paper though it.

7. Remove and inspect the accumulator belt cleaner assembly. Is the
accumulator belt cleaner assembly clean and with no obvious toner
leakage? If not clean or replace the accumulator belt cleaner assembly, if
necessary.

8. With the accumulator belt cleaner assembly removed, inspect the
accumulator belt cleaner end of the auger. Is the auger clogged? Clean
the printer interior.

9. Remove the rear cover.
10. With the accumulator belt cleaner assembly removed, watch the auger
drive gear as you manually rotate the paper feed motor. Does the fuser
drive assembly rotate the auger drive gear? If not, replace the fuser drive
assembly.

11. As you manually rotate the paper feed motor place your finger inside the
auger opening and feel the movement of the auger spring. Does the
auger spring rotate when you manually rotate the paper feed motor? If
not, replace the auger assembly.

12. Replace the imaging unit.
Service Guide

55

Repetitive mark appears on each print

3041-48

An identical mark or image appears on each, or every other, printed image.

1. If spots repeat every 264 mm (10.4 in.) or appear to move in the direction
of paper travel from print to print, replace the imaging unit. If a defect
repeats in exactly the same place on successive prints, replace the
accumulator belt assembly.

2. If a problem repeats every 117 mm (4.5 in.), replace the fuser. If a problem
repeats every 107 mm (4.25 in.), replace the fuser roll cartridge.

3. An 88 mm (3.5 in.) smear may occur on the first print made after a new
imaging unit is installed due to the misalignment of the imaging unit’s gear
teeth with its drive gear. Once printing starts, the teeth will mesh properly
and the problem will disappear.

4. A defect every 58 mm (2.5 in.) or less is related to the feed or exit rollers.

Residual image or ghosting
There are faint, ghostly images
appearing on the page. The images
may be either from a previous page or
from the page currently being printed.
The printer displays no error code.

3041-49

1.

Was the customer printing
numerous copies of the same
image? Avoid printing numerous
copies of the same image.

2.

Generate a test print and open the
front cover just before the sheet of
paper enters the fuser.

3.

Remove the imaging unit.

4.

Inspect the image on the drum. Is
there a normal image, without
ghosts, visible on the drum? If no,
replace the erase lamp. (A failing
high-voltage power supply can
also cause ghosting.)

5. If the customer is consistently printing 250 B-size (500 A-size) prints a day,
recommend the Hi-Duty Fuser Roll Cartridge. If fuser damage is
excessive, replace fuser and install Hi-duty Fuser Roll Cartridge.

56

Phaser 780 Color Printer

6. Replace the imaging unit. Excessive duplexing of the same image can
cause ghost images on the imaging unit drum from fuser oil
contamination.

7. Inspect the image on the surface of the accumulator belt? Is there a
normal test print image, without ghosts, visible on the surface of the
accumulator belt? If a ghost is present, visually inspect the operation of
the cleaner cam solenoid and the cleaner cam guides located on the fuser
assembly. If no ghost is present, replace the accumulator belt cleaner
assembly.

8. Generate a test print and open the front cover just as the sheet of paper
exits the fuser.

9. Inspect the image on the sheet of paper just after the paper exits the Fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has ghost images after it exits the fuser? If yes,
replace the fuser roll cartridge.

10. If ghosting continues, replace the fuser.

Background contamination
There is toner contamination on all or
most of the page. The contamination
appears as a very light gray dusting.
The printer displays no error code.

1. Print Service Print 2 and open
the front cover just before the
sheet of paper enters the fuser.

2. Remove the imaging unit.
Inspect the image on the drum.
Is there a normal test print
image, without background
contamination, visible on the
drum? If not, replace the high
voltage power supply.

3. Inspect the image on the

3041-50

surface of the accumulator
belt? Is there a normal test
print image, without
background, visible on the
surface of the accumulator
belt? If not replace the
accumulator belt assembly.

4. Print service Print 2 and open the front cover just as the sheet of paper
exits the fuser.

5. Inspect the image on the sheet of paper just after the paper exits the fuser.
Is there a normal test print image on the sheet of paper before entering the
fuser but the image has background after it exits the fuser? If so, replace
the fuser roll cartridge.

6. If background contamination continues to occur after 20 prints, replace
the fuser.
Service Guide

57

Unfused image or image easily rubs off of page
The toner image is not completely
fused to the paper. The image
easily rubs off. The printer displays
no error code.

1. Is the image density very
light? If light, but not blank,
go to the earlier topic “Light
(undertone) prints” on
page 44.

2. Check the media weight and
settings at the printer driver.

3. Check the defaults set at the
front panel for media size
and type.

4. Is the printed image fused to
the paper. If not, replace the
fuser.
3041-51

5. Replace the low voltage
power supply

6. Replace the engine control board

Toner on back of print
There is toner on the back of the
printed sheet of paper.

1. Clean the printer interior
2. Inspect the paper that is loaded
in the paper trays. Is the paper
clean and free of toner?

3. Generate a test print and open
the front cover just before the
sheet of paper reaches the
second bias transfer roller, about
one second after the registration
solenoid actuates.

4. Slide the paper feeder out of the

3041-52

printer and inspect the back of
the sheet of paper. Is the back of
the sheet of paper clean and free
of toner? If not clean the paper
feeder and its metal and rubber
registration rollers.

5. Generate a test print and open the front cover just before the sheet of
paper reaches the fuser.

58

Phaser 780 Color Printer

6. Open the front cover and inspect the back of the sheet of paper. Is the
back of the sheet clean and free of toner? If not, replace the second bias
transfer roller and if necessary also replace the accumulator belt cleaner
assembly.

7. Generate a test print and open the front cover just as the sheet of paper
exits the fuser.

8. Slide the fuser out of the printer and inspect the back of the sheet of
paper. Is the back of the sheet of paper clean and free of toner when it
exits the fuser? If not, clean the fuser rollers, by processing 10 sheets of Bsize paper through the printer, or replace the fuser.

9. Generate a test print and open the upper exit cover just as the sheet of
paper reaches exit roller.

10. Inspect the back of the sheet of paper. Is the back of the sheet of paper
clean and free of toner as it nears the exit roller? If not, clean or replace
the upper exit assembly.

Print is mottled
The printed image has a mottled
appearance.

1. Ensure good quality laser paper is
being used.

2. Check the media settings at the
printer driver and at the front
panel default settings for media
size and type.

3. Does mottling occur on only one
color? If yes, remove the top cover
and inspect the magnetic rollers of
the affected color’s developer
assembly. Ensure there is no
buildup. Replace the developer if
necessary.

4. Print Service Print 2 and open the
3041-53

front cover just before the sheet of
media exits the fuser. Remove the
imaging unit and inspect the image
on the drum. Is there a normal
image without mottling. If not
replace the imaging unit.

5. Inspect the image on the accumulator belt. Is there a normal image without
mottling on the belt? If not, replace the accumulator belt assembly.

6. Print a test print and open the front cover just before the sheet of media
reaches the fuser. Is there a normal image on the print without mottling. If
not replace the second bias transfer roller.

7. If the image on a print is normal before it passes through the fuser but
mottled afterwards, replace the fuser roll cartridge. If the problem
persists, replace the fuser.
Service Guide

59

Image mis-registered on paper
The image area is not centered on the
page or the image is bleeding off of
the page. The printer displays no error
code.

1. Is the correct weight paper
correctly loaded in the tray(s)
or multi-purpose tray? Ensure
the paper guides are correctly
set.

2. Clean or replace the pick rollers.
3. Print Service Print 3 and slide

3041-54

the paper feeder out about 10
seconds after pressing Print.
The paper should be evenly
pre-registered 6 mm (1/4 in.)
from the mylar registration
guide. If correctly registered,
test the registration clutch.
Clean the registration rollers. If
not, test the pick solenoid of the
tray being used. Replace if
needed.

4. Replace the paper feeder.
5. Replace the engine control board.

Color layer not correctly registered
The four color images are not
registered correctly and do not form a
clean, four color image on the page.
The printer displays no error code.

1. Ensure the shipping blocks
are removed from the paper
feeder.

2. Test the accumulator belt home
sensor. Replace it if necessary.

3. Replace the engine control
board.

4. Replace the image processor.
5. Replace the accumulator belt
assembly.

3041-55

60

Phaser 780 Color Printer

Color representation not correct
The color of the printed image is
completely different than the
computer image. The printer
displays no error code.

1. Ensure driver settings are
correct. Reload the printer
driver software.

2. Clean and inspect the autodensity calibration sensor.
Test the sensor using the
printer’s built-in diagnostics.

3. Replace the image processor.
4. Replace the engine control
board.

5. Replace the carousel home
sensor.
3041-56

Oil stain or gloss variation on print

3041-57

Variations in glossiness in solid fills may occur near the oil roll cartridge end of
life or with printers running excessively high daily print volumes. If the
customer is consistently running a high volume of prints per day, they should
user the high-capacity fuser roll cartridge.

1. An oil stain may occur on first print after the printer has been idle for an
extended period. If the problem persists on sucessive prints, replace the
oil roll cartridge. Look for excessive oil around the fuser.

2. Check the media in the tray. Try new media.
3. Glossiness variations in solid fills may occur near the oil roll cartridge end
of life or with printers running high daily print volumes. On coated
paper, a variation in glossiness may occur 118 mm from the print’s
leading edge.

Service Guide

61

Random spotting
There are spots of toner randomly
scattered across the page.

1. Slide the paper feeder out of
the printer and inspect the
top of the registration chute
assembly. Is the top of the
registration chute assembly
free of toner? If not, remove
and inspect the waste toner
cartridge. Make sure the
cartridge is not damaged or
leaking.

2. Remove and inspect the

3041-58

imaging unit. Is the exterior of
the imaging unit clean and
with no obvious toner
leakage? If not, remove and
inspect the waste toner
cartridge. Make sure the
cartridge is not damaged or
leaking.

3. Turn the carousel frame and inspect the four developer assemblies. Does
each developer assembly appear clean, without any obvious toner on the
exterior of the assembly or falling from the magnetic brush? Clean the
dirty developer assembly. If the problem reoccurs, replace the faulty
developer assembly.

4. Inspect the fuser. Is the fuser free of toner? Clean the fuser, if necessary.
5. Remove and inspect the accumulator belt cleaner assembly. Is the
accumulator belt cleaner assembly clean and with no obvious toner
leakage? If not clean or replace the accumulator belt cleaner assembly, if
necessary.

6. With the accumulator belt cleaner assembly removed, inspect the
accumulator belt cleaner end of the auger. Is the auger clogged? Clean the
printer interior.

7. Remove the rear cover. With the accumulator belt cleaner assembly
removed, watch the auger drive gear as you manually rotate the paper
feed motor. Does the fuser drive assembly rotate the auger drive gear? If
not, replace the fuser drive assembly.

8. As you manually rotate the paper feed motor place your finger inside the
auger opening and feel the movement of the auger spring. Does the auger
spring rotate when you manually rotate the paper feed motor? If not,
replace the auger assembly.

9. Replace the imaging unit.

62

Phaser 780 Color Printer

Media jams and the paper path
Skewed image
The image area is twisted or is not parallel with the sides of the page. The printer
neither jams nor displays an error code.

1. Check that the paper tray’s metal hooks (at the corners of the leading
edge of the paper in the tray) are not bent or deformed.

2. Feed paper out of each of the available paper feeders. Does the image
skew when fed out of one tray but not when fed out of the others? If yes,
Inspect the paper and tray of the feeder that is skewing to ensure the tray
is correctly loaded and the paper is good.

3. Replace the multi-purpose tray pick-up roller or the main tray feed roller.
4. Print a test print and slide the paper feeder out about 10 seconds after
pressing PRINT. Carefully slide the paper feeder out of the printer and
inspect the position of the sheet of paper. Is the sheet of paper parallel to
the edges of the paper feeder? If not, replace the turn roller assembly.

5. Generate a test print and slide the fuser out of the printer just as the sheet
of paper is moving through the registration rollers. Carefully slide the
paper feeder out of the printer and inspect the position of the sheet of
paper. Is the sheet of paper parallel to the edges of the paper feeder as it
leaves the registration rollers? If no, clean or replace the feeder rubber
registration roller.

6. Remove second bias transfer roller. Manually raise and lower the cam
levers at the ends of the second bias transfer roller. Are the cam levers
undamaged? When you raise the levers does the second bias transfer
roller lower and when you release the levers does the second bias transfer
roller raise? Do the cam levers have a strong spring action? If not, replace
the second bias transfer roller.

Service Guide

63

Damaged prints
The printed page exits the printer either wrinkled, creased, or torn. The printer
neither jams nor displays an error code.
The following components are associated with this specific problem. One or more
of these components may have failed partially or completely. If you cannot isolate
the problem, replace each component listed below, one at a time, until the
problem disappears. Check the media settings at the printer driver.
■

Paper feeder (usually appears without toner in creases or wrinkles)

■

Fuser)

■

Accumulator belt (usually appears with toner in creases or wrinkles)

1. Check that the paper tray’s metal hooks (at the corners of the leading
edge of the paper in the tray) are not bent or deformed.

2. Feed paper out of each of the available paper feeders. Is the paper
damaged when fed out of one tray but not when fed out of the others? If
so, inspect the tray for damage and check the paper to ensure it is correct.

3. Is the paper damaged when fed out of multi-purpose tray? Inspect the
multi-purpose tray for debris or obviously broken components that could
be damaging the paper as it feeds out of the assembly and into the printer.

4. Inspect the paper feeder for debris or broken components?
5. Generate a test print and open the front cover just as the sheet of paper is
moving through the registration rollers (about 1 second after you hear
paper feeding start).

6. Carefully slide the paper feeder out of the printer and inspect the sheet of
paper. Is the sheet of paper undamaged as it leaves the registration
rollers? If yes, replace the metal registration roller and the rubber
registration roller.

7. Generate a test print and open the front cover just before the sheet of
paper reaches the fuser. Open the front cover and inspect the sheet of
paper. Is the sheet of paper undamaged as it leaves the second bias
transfer roller? If yes, replace the second bias transfer roller.

8. Generate a test print and open the front cover just as the sheet of paper
exits the fuser. Inspect the sheet of paper. Is the sheet of paper damaged
as it exits the fuser? If yes, replace the fuser.

9. Generate a test print and open the upper exit cover just as the sheet of
paper reaches exit roller. Inspect the sheet of paper. Is the sheet of paper
undamaged as it nears exit roller? If no, clean or replace the lower exit
assembly and the upper exit assembly. Is the sheet of paper undamaged
until it reaches exit roller? If yes, replace exit roller.

64

Phaser 780 Color Printer

Inoperative lower tray feeder
The lower tray feeder does not work at all, the lower tray feeder does not attempt
to feed paper, and the problem is not identified by a displayed error code.

1. Ensure the printer driver is configured with the “optional trays”
installed.

2. Try printing using a different application program.
3. Try printing using a different printer driver.
4. Try printing from another computer.
5. Check the wire harness that is running between the paper feeder circuit
board to the engine control board. Ensure the wire harnesses are
connected to P/J131 and 132 on the lower feeder circuit interface board

6. Generate test prints from Tray 2, Tray 3, and Tray 4. Does the printer
generate a test print from any of the lower feeder trays? If no, go to
Step 10.

7. Remove the lower feeder rear cover.
8. Measure the voltage between P/J133-B5 and frame ground on the lower
feeder circuit board. Is there +5VDC between P/J133-B5 and frame
ground on the lower feeder circuit board? If not, verify that +5 VDC on
P33-10 the low voltage power supply.

9. Measure the voltage between P/J133-B1 and frame ground and between
P/J133-B2 and frame ground on the lower feeder circuit board. Is there
+24VDC between P/J133-B1 and ground and between P/J133-B2 and FG?
If not, verify the +24VDC on pins 13 and 14 of the low voltage power
supply and the engine control board.

10. Replace the lower tray feeder circuit board.
11. Replace the engine control board.

Power problems
All front panel indicators remain off. The printer does not initialize upon powerup
1. Check to see if the printer is plugged in.
2. Check the power on/off switch.
3. Reset the fuser and the paper feeder.
4. Refer to the topic “Printer will not power up” on page 40.

Service Guide

65

Front panel indications
Media tray indicates missing or empty when it is not
1. If there is media in the tray, then check the media sensors. If the lower
feeder is available, switch trays to verify the source of the problem

2. Check to see if the paper-empty sensor is broken.
3. Run service diagnostics on the media sensors.
4. Check the media selection switch actuators on the rear of the paper tray.
Also check the paper size switches at the rear of the printer frame or the
lower feeder.

Macintosh printing problems
Image never prints
Printer acts as if it is receiving data, but nothing comes out of printer or it goes
back to “Ready” mode without printing image.

1. Power cycle the printer and print again.
2. Make sure that the correct Phaser 780 printer icon was selected in the
Chooser. Try printing the job again.

3. In the Chooser or the print dialog, switch background printing to off. Try
printing the job again.

4. Ensure that the printer can print by printing an internal front panel test
print.

5. Enable the Error Handler through the front panel and try printing the job
again. If an error page is printed after printing the job again, call the
Customer Support Hotline for further assistance. Please have the error
page in hand.
If available, try printing to a black-and-white PostScript printer (such as
an Apple LaserWriter). If the file does not print on the black-and-white
PostScript printer, this may mean that the problem may be application- or
network-related.

Image prints in black-and-white
1. In the print driver dialog box, make sure the Color/Grayscale option has
been selected.

2. Check the version of your LaserWriter driver to ensure that it is version
6.0.7 or higher. Earlier versions of the driver do not support color
PostScript. The application may require special instructions to print.

3. Ensure the driver setting TekColor is not set to Monochrome mode.

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Phaser 780 Color Printer

Image is rotated 90 degrees
1. In the application's Page Setup, make sure that the image is selected to
print in portrait or landscape orientation to match the document. Also
ensure the selected paper size is correct.

2. Ensure that the printer can print by printing an internal front panel test
print.

3. Enable the Error Handler through the front panel and try printing the job
again. If an error page is printed after printing the job again, call the
Customer Support Hotline for further assistance. Please have the error
page in hand.
If available, try printing to a black-and-white PostScript printer (such as
an Apple LaserWriter). If the file does not print on the black-and-white
PostScript printer, this may mean that the problem may be application- or
network-related.

Windows printing problems
Image never prints
Printer acts as if it is receiving data, but nothing comes out of printer or the
printer goes back to “Ready” mode with out printing image.

1. Under the printer's setup options, set RETRY = 850
2. Try printing from the printer driver.
3. Try printing from another application.
4. Try printing to another printer.
5. Try printing from another computer.
6. Try printing an internal front panel test print.

Blue color on the screen is printing too purple.
Many applications describe color as percentages of a video display screen’s
primary colors: red, green, and blue (RGB). When a printer translates these RGB
colors into its own primaries of cyan, magenta, and yellow (CMY), blue is often
printed as purple.

1. To adjust blue from within Microsoft Windows: Within the Tektronix
PostScript Windows driver you have an option, Vivid Color, that alters
to blue colors that are appearing purple.
To Access this option, select:
Printer Control Panel
Right click Printer Driver
Choose Properties
Choose Color Corrections
Select Vivid Color

Service Guide

67

Printing from Windows 3.1 produces the message “Problem writing device
LPT1: Cancel or Retry”.
Option #1:

1. Select Printers, and click Configure.
2. Change the port selection from LPT1 to LPT1.OS2.
3. The MODE command disables DOS timeouts. The LPT1.OS2 selection
forces Windows to print through DOS instead of directly to the printer.
Option #2: The solution above does not allow users to spool documents using the
PrintManager. To use the PrintManager as well as correcting time-out problems,
edit the following line in the win.ini file:
TransmissionRetryTimeout=45 to:
TransmissionRetryTimeout=850
In Windows 3.1:

1. Follow the above instructions for issuing the MODE command in DOS.
2. Start Windows.
3. Select the Control Panel from the Main menu.
4. Select Printers
5. Select the appropriate printer and click on Connect.
6. Uncheck the Fast Printing Direct to Port box.

Workstation printing problems
Image never prints
Printer acts as if it is receiving data, but nothing comes out of the printer or the
printer goes back to “Ready” mode without printing an image.
For serial or parallel printing. Ensure that the print file ends with a “CTRL-D”
character. CTRL-D indicates the end-of-file, which the printer responds to by
closing host-to-printer communications and then processing and printing the file.
Use a text editor to open and examine the file. There is a utility file that you can
use to tag or remove a CTRL-D to the end of a print file. TCP/IP and Novell
protocols do not accept CTRL-D with the print files. Refer to the network user
manual.

68

Phaser 780 Color Printer

Running built-in diagnostics
The printer diagnostic interface consists of a front panel containing a 2 line by
40 character LCD display and six buttons. For diagnostics, the front panel
switches are identified as 1 through 6 with switch 1 being the left-most switch
and switch 6 being the right-most switch.

To place the printer in service diagnostics mode. Turn on the printer and wait for a
string of “ ” to appear on the front panel display, as they appear, press and hold
button 3 for five seconds. You select individual test by navigating a tree-structure
with three buttons defined as Prev, Next, and Select.

*

Help Mode. You can enter a Help mode at the top level by pressing Prev or Nest
until Help Mode On/Off is displayed. Once you select Help mode and “H” is
displayed on the lower-right corner of the display. With help mode enabled, once
you select a test, information about the test is displayed in the top line of the
display. Buttons 3 and 4 are relabeled as Quit and More. Pressing More displays
additional information about the test. Pressing Quit leaves the test description
and asks if you want to run the test.
Table 1 Diagnostic tests
Test

Sub-tests

Detail

Service Print

Source

Tray 1
Tray 2
Tray 3
Tray 4
MPT

Output

Right Side
Top Cover

Media

Paper
Transparency
Label
Cover

Print

Black Grid
Color Grid
Black Patch
Color Patch

Paper Path Test
Image Processor

Kernel, DIMMs, ROMs,
I/O

Engine ROM Revision

Service Guide

69

Table 1 Diagnostic tests
Test

Sub-tests

Sensors

Belt Home Sensor

Detail

Carousel Home Sensor
Waste Cartridge Sensor
Waste Cartridge Full
Sensor
Full Stack Sensor
Exit Sensor
New Toner Sensor
Toner Cartridge Present
Sensor
Paper Feeder Interlock
MPT Long Paper Sense
MPT Paper Sensor
MPT Edge Sensor
Registration Sensor
Oil Roller Switch
New Oil Roller Switch
Fuser Interlock Switch
Fuser Entry Sensor
Fuser Exit Sensor
Front Cover Interlock
Lower Feeder Interlock
Tray 1 Present
Tray 2 Present
Tray 3 Present
Tray 4 Present

70

Phaser 780 Color Printer

Indicates Missing or Size
of media selection

Table 1 Diagnostic tests
Test

Sub-tests

Sensors (cont.)

Tray 1 Low Sensor

Detail

Tray 1 Empty
Tray 2 Low Sensor
Tray 2 Empty
Tray 3 Low Sensor
Tray 3 Empty
Tray 4 Low Sensor
Tray 4 Empty

Motors/Solenoids

Auto-density Calibration
Sensor

Pass/Fail test of sensor
and its wiper solenoid;
for solenoid portion of
test, listen for clicks of
sensor wiper solenoid.

Process Motor

Slow/Fast

Paper Feed Motor

On/Off

Laser Motor

On/Off

Toner Dispense Motor

One Time

Lower Feeder Motor

On/Off

MPT Feed Clutch
MPT Pick Solenoid
MPT Pre-Registration
Clutch
MPT Registration Clutch
Developer Clutch
Second Bias Transfer
Clutch
Oil Roller Solenoid
Belt Cleaner Solenoid
Tray 2 Pick Solenoid
Tray 3 Pick Solenoid
Tray 4 Pick Solenoid
Tray 2 Feed Clutch

Service Guide

71

Table 1 Diagnostic tests
Test

Sub-tests

Motor/Solenoids (cont.)

Tray 3 Feed Clutch

Detail

Tray 4 Feed Clutch

Front Panel

Rear Fan

Slow/Fast Speed

Fuser Fan

Slow/Fast Speed

Erase lamp

On/Off

Fuser Lamp (heater)

On/Off

Front Panel Display
Front Panel LEDs

Life Data

Save Life Count
Restore Life Count

The Save function copies
all consumable and FRU
counts from the engine
control board NVRAM to
the image processor
board. The Restore
function returns the
values to the engine
control board NVRAM.
The Save function must
be performed prior to
replacing the engine
control board. Perform
the Restore function
after the replacement

Drum Unit Life
Yellow Toner Life
Magenta Toner Life
Black Toner Life
Cyan Toner Life
Printer Life
Bias Transfer Roller Life
Belt Cleaner Life
Fuser Oil Life
Fuser Unit Life
Reset Fuser Life
Reset Bias Transfer
Roller Life
Reset Belt Cleaner Life

72

Phaser 780 Color Printer

Perform the appropriate
reset function whenever
one of these FRUs is
replaced to return that
FRUs copy count to zero

Adjustments
This topic discusses using the front panel’s interactive mode to review and
change the printer’s operation. It also contains the procedures to calibrate the
printer after you replace key Field Replaceable Units and to evaluate the printer's
functionality.

Printing test prints
The prints printed via the front panel the are generated by the image processor.
While the printer is idle you can use the front panel to print an image stored in the
image processor such as the configuration page.

Print service test prints
The service prints allow you to evaluate the printer’s print quality.

1. Press the Printer Menu Select button.
2. Select the Help Pages.
3. Scroll to either Service Print 1 or Service Print 2 and press
Print.

Printing the configuration page
The configuration page shows a great deal of information regarding the data and
set-up values stored in NVRAM. In the same Help pages menu you can also print
the startup page.

1. Press the Printer Menu Select button.
2. With the Help pages menu displayed, scroll to the Configuration
Page menu item. Press Print.

Printing the demonstration pages
Demo pages demonstrate the capabilities of the printer.

1. Press the Printer Menu Select button.
2. With the Help pages menu displayed, scroll to the Demonstration
Page item. Press Print.

Service Guide

73

Print engine calibration
Generally, only one print engine calibration is required. Usually, if you note a
print defect, replacing a toner cartridge, a developer or the imaging unit or
perhaps the paper feeder corrects the problem.

Adjusting for impulse banding
Impulse banding is a print artifact that occurs on prints when the developer roller
comes into contact with the drum. This adjustment adds shims to the carousel
assembly to slightly alter the position of each developer assembly relative to the
drum.

Note

The shims used in this adjustment permanently clip into place
and can be difficult to remove. You should modify a set of shims
by cutting the clips off of the shims so they can be inserted and
removed easily. Once you determine the correct shims required,
install permanent shims in their place.

1. Ensure the printer is in a ready-to-operate condition.
2. Turn off the printer.
3. Remove the top cover.
4. With a pen or marker (no pencil), scribe a line across the white tracking
roller located at the front of the developer roller.

5. Position the white roller so the mark is even with the edge of the nearly
developer frame.

6. Hold the carousel lock so it will not impede the carousel’s movement.
7. With a slow, smooth action, rotate the carousel assembly 180o. Do not
allow the carousel to stop as the developer pass the drum surface.
Continue rotating the carousel to bring the marked developer to its
starting position.

8. As the developer roller contacts and passes the drum surface, the
developer should rotate about 2 mm. Too much rotation, caused by the
roller contacting the drum too soon, causes impulse banding.
Inspect the white tracking roller for movement. If the mark is within
2 mm of its original position, no adjustment is needed.
If the mark is rotated beyond 2 mm, a shim is required.

9. Generally, a 1 mm shim usually corrects impulse banding. Install a
shim in the side of the carousel assembly for the developer being tested.

10. Repeat the procedure from Step 5 until the rotation is about 2 mm. If
rotation is not enough, use a smaller shim. Too much, use a larger shim.

11. Repeat for each developer.
74

Phaser 780 Color Printer

Developer
roller

Place mark on
white roller

After carousel rotation
mark should move 2mm
Install shim

Lift up slightly
to install shim

Toner
Adjusting for impulse banding

3041-32

Service Guide

75

76

Phaser 780 Color Printer

Cleaning and
Maintenance
Service preventive maintenance procedure
Whenever you check, service, or repair a printer, you should perform the following
procedures. Cleaning the printer, as outlined in the following steps, assures proper
operation of the printer and reduces the probability of having to service the printer in
the future.
The frequency of use and the type of paper a customer prints on will, in large part,
determine how critical cleaning the machine is. Users of ordinary Bond paper (copier
paper) should have very few problems since this paper is smooth and relatively dustfree. You should thoroughly inspect and clean these printers.
Ask each printer customer about the type of paper he or she uses so that you can be
sure to clean the parts of the printer that particular paper may affect. If a customer is
printing on the more unusual or dustier papers, then you should pay particular
attention to these printer parts:
■

The standard pick roller

■

The multi-purpose pick roller

■

The feed rollers

■

The cabinet interior

■

The exit rollers

Recommended tools
■

Toner vacuum cleaner

■

Suction bulb (air blower)

■

Cleaning water

■

Lint-free wipes

■

Cotton swabs

■

Imaging unit cover

■

Isopropyl alcohol (greater than 90% pure)

Service Guide

77

Cleaning
Caution

Never apply alcohol on the second bias transfer roller.
Never apply alcohol to the fuser rollers.

1. Turn off the printer.
2. Remove the imaging unit and cover it to protect it from the light.
3. Remove the toner cartridges.
4. Slide out the fuser.
5. Remove the paper tray.
6. Slide out the paper feeder.
7. Clean all printer rollers, except the second bias transfer roller and the
fuser rollers, with alcohol-dampened wipes only.

8. Clean the laser window with puffs of air from the suction bulb.
Alternately, you can vacuum the window clean.

9. Wipe off the pre-exposure erase lamp with a lint-free wipe.
10. Vacuum out the interior of the printer.
11. Vacuum loose toner out of the carousel assembly.
12. Remove and clean the accumulator belt cleaner assembly. Removing
the accumulator belt cleaner assembly is explained on the Phaser 780
Service CD-ROM. Once removed, gently vacuum the cleaner assembly
using a vacuum with a brush attachment. Do not touch the cleaner
blade with your hands nor bend or crease the film seal.

13. If you must clean the fuser rollers, never clean them with alcohol. First
clean the fuser rollers by processing 10 sheets of paper through the
printer. If more cleaning is needed, clean the rollers with a soft, lintfree cloth with either fuser oil or water.

78

Phaser 780 Color Printer

Resetting NVRAM
Resetting NVRAM returns all the image processor's NVRAM-stored parameters
to their factory defaults except the print counts and the Adobe firmware serial
number.

Caution

Resetting NVRAM will also reset the network card’s NVRAM.
If possible, copy down all network parameters or print the
Configuration Page.

To reset the image processor to its factory default values, follow this procedure:

1. Turn on the printer

*

2. When the row of “ ”, begins to be displayed on the front panel, press
and release button 1 and then press and release button 4.

3. When the front panel displays “Password?”, press and release button 1,
then press and release button 3. The display responds with the message
“Resetting NVRAM.” Following NVRAM reset, the print powers up
normally.

Service Guide

79

80

Phaser 780 Color Printer

Key FRU Disassembly
This topic illustrates how to remove and replace key printer Field Replaceable
Units (FRUs). Refer to the later topic “FRU List” on page 137 for a list of the
printer’s FRUs. For more detailed removal/replacement procedures refer to the
Phaser 780 Service CD-ROM.

Service Guide

81

Paper feeder
1. Slide the paper feeder far enough out of the printer so you can reach the
assembly rails.

2. Push in on the front rail latch as you slide the front of the paper feeder
out far enough to disengage the latch.

3. Push in on the rear rail latch as you slide the rear of the paper feeder out
far enough to disengage the latch.

4. Slide the paper feeder out of the printer.
Reverse these steps to install the paper feeder.

Rear latch

Front latch

780-5-34

Removing the paper feeder

82

Phaser 780 Color Printer

Feeder registration chute
1. Slide the paper feeder out of the printer. You do not need to remove the
paper feeder.

2. Remove the E-ring securing the rear arm of the registration chute to the
paper feeder.

3. Remove the screw securing the ground wire to the chute. Remove the
wire.

4. Open the registration chute.
5. Slide the chute to the rear and remove the chute.
Reverse these step to install the registration chute.

Registration
chute

Ground
wire

780-5-37

Removing the registration chute
Service Guide

83

Feeder registration clutch
1. Remove the paper feeder as described in “Paper feeder” on page 82.
2. Turn over the paper feeder and disconnect the wiring harness from the
registration clutch.

3. Open the registration chute.
4. Remove the E-ring securing the registration clutch to the rear of the
metal registration roller. Remove the registration clutch from the roller.
Reverse these steps to install the registration clutch.

Registration clutch

Wiring harness
780-5-40

Removing the registration clutch

84

Phaser 780 Color Printer

Registration brake clutch
1. Remove the paper feeder as described in “Paper feeder” on page 82.
2. Turn the paper feeder over and disconnect the wiring harness from the
registration brake clutch.

3. Remove the three screws securing the registration brake clutch
assembly to the side of the paper feeder. Remove the assembly.

4. Remove the E-ring securing the registration brake clutch to the clutch
shaft and remove the clutch.

5. Remove the E-ring securing the registration brake gear to the gear shaft.
Remove the gear.
Reverse these steps to install the registration brake clutch.

Wiring harness

Registration brake
assembly

Registration brake gear

Registration brake
clutch

780-5-46

Removing the registration brake clutch
Service Guide

85

Feeder metal registration roller
1. Remove the feeder registration clutch as described in “Feeder
registration chute” on page 83.

2. Remove the registration brake clutch as described in “Registration
brake clutch” on page 85.

3. Remove the E-ring securing the out gear at the front end of the metal
registration roller. Remove the gear.

4. Remove the rear bearing from the metal registration roller.
5. Slide the metal registration roller to the rear, slide the front of the roller
out of the front bearing, and remove the roller from the main paper
feeder.
Reverse these steps to install the feeder metal registration roller.

Metal registration roller
Rear bearing

Front bearing
Out gear
780-5-41

Removing the metal registration roller

86

Phaser 780 Color Printer

Feeder rubber registration roller
1. Remove the feeder metal registration roller.
2. Remove the E-ring at the front of the rubber registration roller securing
the gear to the roller. Remove the gear.

3. Remove the E-ring securing the rear of the rubber registration roller to
the paper feeder.

4. Remove the rear bearing and black spring from the rear end of the
rubber registration roller.

5. Slide the rubber registration roller out of the paper feeder. Note the
silver spring and bearing on the front end of the roller.
Reverse these steps to install the feeder rubber registration roller. The front
portion of the shaft is longer than the rear.

Rear bearing
Rubber registration roller
Rear
spring
(black)

Front
bearing

Gear

Front spring (silver)

780-5-42

Removing the rubber registration roller

Service Guide

87

Feeder pre-registration clutch
1. Remove the paper feeder.
2. Remove the feeder registration chute.
3. Turn over the paper feeder and disconnect the wiring harness from the
feeder pre-registration clutch.

4. Remove the two screws securing the feeder pre-registration gear
assembly to the paper feeder. Remove the gear assembly.

5. Remove the E-rings securing the feeder pre-registration clutch and the
pre-registration gear to the pre-registration support. Remove the
support.

6. Slide the feeder pre-registration gear off the shaft.
7. Undress the J95 wiring harness and slide the feeder pre-registration
clutch off the feeder pre-registration shaft.

Pre-registration
clutch
Pre-registration
gear

P/J95

Pre-registration
support

Pre-registration
gear assembly

780-5-39

Removing the feeder pre-registration clutch
88

Phaser 780 Color Printer

Feeder pre-registration rollers
1. Remove the feeder pre-registration clutch as explained in the previous
procedure.

2. Slide the blue feeder pre-registration knob off the feeder preregistration shaft.

3. Remove two screws securing the multi-purpose tray out holder to the
paper feeder. Pull the holder away from the feeder.

4. Remove the E-ring and front bearing securing the front of the feeder
registration shaft to the paper feeder frame.

5. Remove the E-ring and rear bearing securing the idler gear to the rear of
the feeder pre-registration shaft. Remove the idler gear.

6. Lift the pre-registration roller up.
7. Slide the feeder pre-registration roller to the rear of the paper feeder,
freeing the front of the shaft from front of the paper feeder.

8. Slide the feeder pre-registration roller to the front, free the rear of the
shaft from the rear of the paper feeder.

9. Slide the feeder pre-registration roller free of feeder pre-registration
gear 2. Remove the shaft.

Note

For reassembly, ensure the shaft pin lines up with the slot in preregistration gear 2.

Service Guide

89

Front
bearing
Idler gear

Pre-registration
knob
Out holder
Pre-registration gear 2
Pre-registration roll shaft

780-5-38

Removing the feeder pre-registration roller

90

Phaser 780 Color Printer

Paper-pick turn roller
1. Remove Tray 1 from the printer.
2. Remove the paper feeder.
3. Remove the two screws securing the turn chute to the printer frame.
Remove the turn chute.

4. Remove the paper-pick turn chute.
5. Remove the two screws securing the tray stopper to the printer frame.
Remove the stopper.

6. Remove the E-ring securing the front of the turn roller shaft to the front
bearing.

7. Disconnect the turn arm spring from the printer frame.
8. Remove the E-ring securing the round cover over the turn-arm gear.
Remove the cover.

9. Slide the rear of the turn roller shaft out of the turn-arm assembly.
10. Slide the front of the turn roll shaft out of the front bearing. Remove the
turn roller.

Front bearing

Turn roller
spring

Turn chute

Tray stopper

780-5-14

Removing the paper-pick turn roller
Service Guide

91

Paper feed drive gear train
1. Remove the high voltage poser supply as described in “High voltage
power supply” on page 132.

2. Slide the paper feeder out of the printer.
3. Remove the screw securing the wire clip to the paper-feed drive gear
train. Move the clip and harness out of the way.

4. Remove the five screws securing the paper-feed drive gear train to the
printer frame. Remove the gear train.

5. Remove the two wire clamps from the paper-feed drive gear train.
Reverse these steps to install the paper-feed drive gear train.

Wire clip

Wire clamps

Paper feed drive gear train
Removing the paper-feed drive gear train

92

Phaser 780 Color Printer

780-5-73

Paper-feed motor
1. Remove the rear cover.
2. Disconnect the wiring harness from the paper-feed motor.
3. Remove the four screws securing the paper-feed motor to the fuser
drive gear train. Remove the motor.

4. Remove the two motor supports.
Reverse these steps to install the paper-feed motor.

Paper feed
motor

Motor
supports

Wiring harness

780-5-75

Removing the paper-feed motor

Service Guide

93

Multi-purpose tray roller assembly
1. Remove the multi-purpose tray top, front and rear covers.
2. Unhook the pick-up spring from the pick-up gear.
3. Release the latches holding the pick-up gear to the pick-up shaft. Slide
the pick-up gear, pick-up cam gear, and lever stopper off the shaft.

4. Remove the E-ring securing the rear shaft bearing to the rear of the
multi-purpose tray.

5. Remove the E-ring securing the front shaft bearing to the front of the
multi-purpose tray.

6. Slide the multi-purpose tray roller assembly out of the multi-purpose
tray assembly.

Lever stopper

Pick up cam gear

Rear bearing
Pick-up
gear

Front
bearing

780-5-27

Removing the multi-purpose tray roller assembly
94

Phaser 780 Color Printer

Multi-purpose tray pick rollers
Note

Replace the pick rollers as a set.

1. Remove the multi-purpose tray top cover.
2. Release the latch holding the front pick roller core to the pick up shaft
and slide the core away from the front pick roller.

3. Slide the front pick roller toward the front roller core, so the pick up roll
clears the locking pin. Remove the front pick roller.

4. Release the latch holding the rear roller core to the pick roller shaft and
slide the roller away from the rear pick roller.

5. Slide the rear pick up roller toward the rear roller core, so the pick roller
clears the locking pin. Remove the rear pick roller.

Service Guide

95

Reverse these steps to install the multi-purpose tray pick rollers. Note the arrows
molded into the sides of the pick roller; ensure they are oriented the correct
direction upon installation.

Latch
Pick-up rollers

Printer front

Front core rollers

Rear core rollers

780-5-26

Removing the multi-purpose tray pick rollers

96

Phaser 780 Color Printer

Auto-density calibration sensor
Caution

Protect the accumulator belt with a sheet of paper.

1. Remove the imaging unit. Remove the inner cover.
2. Disconnect the wiring harness from the auto-density calibration sensor.
3. Remove the E-ring securing the front of the auto-density calibration
sensor to the front of the printer frame.

4. Reach inside the printer cavity and slide the front end of the autodensity calibration sensor out of the hole at the front of the printer.

5. Pull the wiring harness out through the grommet hole.
Caution

Do not touch or scratch the accumulator belt when removing the
auto-density calibration sensor.

6. Lift the rear end of the auto-density calibration sensor out of the cutout
at the rear of the printer. Remove the sensor.
For reassembly, ensure the rear of the sensor is fully installed in the rear cutout.

Service Guide

97

Rear cutout

Auto-density
calibration sensor

780-5-48

Removing the auto-density calibration sensor

98

Phaser 780 Color Printer

Developer assembly
1. Open the front cover. Remove the toner cartridge of the developer
assembly to be removed. Remove the imaging unit.

2. Remove the top cover and inner cover.
3. Remove the screw securing the carousel latch to the front of the printer
frame. Remove the latch.

4. Turn the carousel knob until the large shoulder screw, securing the
desired developer assembly to the carousel frame, appears through the
access hole a few inches above the carousel knob.

5. Remove the shoulder screw securing the developer assembly to the
carousel frame. Keep the carousel in this position.

6. Reach in through the top of the printer; slide the developer assembly to
the front of the printer to free the gears at the rear of the developer
assembly.

7. Lift the front of the developer assembly to free the front of the assembly
from the front of the printer frame. Remove the assembly. Each
developer is keyed to its position in the carousel.

Service Guide

99

Carousel latch

Developer assembly

Shoulder screw
Remove shipping
developer cover
before installing new
developer assembly
Removing a developer assembly

100

Phaser 780 Color Printer

780-5-53

Developer clutch
1. Remove the carousel motor board as described in “Carousel motor
board” on page 108.

2. Disconnect the wiring harness from the developer clutch.
3. Remove the fuser drive train gear as described in “Fuser drive gear
train” on page 126.

4. Remove the four screws securing the developer clutch to the printer
frame. Remove the clutch.
Reverse these steps to install the developer clutch.

Wiring harness
Developer clutch

780-5-81

Removing the developer clutch

Service Guide

101

Developer tie plate
1. Remove the lower exit assembly as described in “Lower exit assembly”
on page 128.

2. Remove the rear cover.
3. Remove the inner cover.
4. Remove the wire and wire clamp from the developer tie plate.
5. Remove the two screws securing the developer tie plate to the rear of
the printer frame.

6. Remove the two screws securing the developer tie plate to the front of
the printer frame.

7. Slide the tie plate up and out of the printer frame.
Reverse these steps to install the developer tie plate.

102

Phaser 780 Color Printer

Developer tie
plate

Wire clamp

780-5-82

Removing the developer tie plate

Service Guide

103

Toner/developer dispense motor
1. Remove the carousel motor board as described in “Carousel motor
board” on page 108.

2. Remove the two screws securing the toner/developer dispense motor
to the printer frame.

3. Slide the toner/developer dispense motor up and slightly to the left to
free the motor shaft gear from the frame. Remove the motor.

4. Disconnect the wiring harness from the toner/developer dispense
motor.

Note

Install the motor using the two left-side mounting screw holes.

Reverse these steps to install the toner/developer dispense motor.

Wiring harness

Toner / developer
dispense motor
Removing the toner/developer dispense motor

104

Phaser 780 Color Printer

780-5-80

Carousel assembly
1. Remove each developer assembly.
2. Remove the knob screw.
3. Remove the screw securing the knob in place. Release the knob latch by
inserting a screwdriver blade through the slot in the front of the knob.

4. Remove the carousel motor.
5. Remove the toner/developer dispense motor.
6. Pull the fuser unit a few inches out of the printer.
7. Remove the low voltage power supply.
8. Remove the fuser drive gear train.
9. Remove the developer clutch.
10. Remove the developer tie plate.
11. Remove the carousel sensor.
12. Remove the large E-ring securing the rear carousel bearing to the rear of
the printer frame. Slide the rear bearing off the carousel frame shaft.

13. Slide the front carousel bearing off of the carousel frame shaft.
14. Slide the carousel frame assembly to the front of the printer frame.
15. Pull the rear of the carousel frame assembly free of the rear frame;
swing the rear of the assembly out of the printer. Remove the assembly.

Service Guide

105

Screw

Carousel
assembly

Rear
bearing

Front
bearing

780-5-54

Removing the carousel assembly

106

Phaser 780 Color Printer

Carousel motor
1. Remove the rear cover.
2. Disconnect the wiring harness from the carousel motor.
3. Remove the three screws securing the carousel motor to the printer
frame. Remove the motor.
Reverse these steps to install the carousel motor.

Wiring
harness

Carousel motor

780-5-78

Removing the carousel motor

Service Guide

107

Carousel motor board
1. Remove the rear cover.
2. Remove the wiring harnesses from the carousel motor board.
3. Remove the screw securing the carousel motor board to the printer
frame. Remove the board.
Reverse these steps to install the carousel motor board.

Wiring harness

Carousel motor board

780-5-79

Removing the carousel motor board

108

Phaser 780 Color Printer

Carousel sensor
1. Remove the developer fan duct.
2. Remove the screw securing the carousel sensor plate to the printer
frame. Remove the plate, along with the attached carousel sensor, from
the frame.

3. Disconnect the wiring harness from the carousel sensor.
4. Squeeze the three latches securing the sensor to the plate and remove
the sensor.
Reverse these steps to install the carousel sensor.

Carousel sensor

Wiring
harness

Carousel
sensor plate

780-5-56

Removing the carousel sensor

Service Guide

109

Laser unit
1. Remove the top cover.
2. Remove the eight screws securing the laser unit cover to the printer
frame and remove the cover.

3. Disconnect the wiring harnesses from the laser diode board.
4. Disconnect the wiring harness from the start-of-scan sensor board.
5. Remove the four screws securing the laser unit to the printer frame.
6. Carefully lift the laser unit off the printer frame. Reach under the unit
and disconnect the wiring harness from the laser unit motor board.

7. Remove the laser unit.
Reverse these steps to install the laser unit.

110

Phaser 780 Color Printer

Laser cover

Laser unit

780-5-47

Removing the laser unit

Service Guide

111

Erase lamp rail assembly
1. Remove the imaging unit.
2. Remove the laser unit as described in “Laser unit” on page 110.
3. Disconnect the wiring harness from the waste cartridge full sensor.
4. Disconnect the wiring harness from the waste cartridge sensor.
5. Free the wiring harnesses from the wire clamps.
6. Disconnect the wiring harness from the erase lamp.
7. Remove the two screws securing the erase lamp rail assembly to the
front of the printer frame.

Caution

Be careful not to damage the accumulator belt underneath the
erase lamp rail assembly.

8. Lift the erase lamp rail assembly up through the top of the printer
frame.
Reverse these steps to install the erase lamp rail assembly.

112

Phaser 780 Color Printer

Disconnect wiring harnesses

Wire clamps

Erase lamp
rail assembly

780-5-50

Removing the erase lamp rail assembly

Service Guide

113

Erase lamp
1. Remove the erase lamp rail assembly as described in “Erase lamp rail
assembly” on page 112.

2. Release the three latches holding the erase lamp assembly to the erase
lamp rail assembly. Remove the lamp.
Reverse these steps to install the erase lamp.

Erase lamp

Erase lamp latch
Removing the erase lamp

114

Phaser 780 Color Printer

780-5-49

Process drive unit
1. Remove the imaging unit.
2. Remove the paper feeder.
3. Remove the paper feeder drive assembly.
4. Remove the erase lamp rail assembly.
5. Disconnect the wiring harness leading to the process motor. Unhook
the wires from the wire harness clip attached to the process drive unit.

6. Remove the screw securing the high voltage power supply bracket.
Move the bracket out of the way.

7. Inside the printer frame, remove the two screws securing the process
drive unit to the rear of the accumulator belt assembly.

8. Hold the process drive gear train, it is heavy, while you remove the
seven screws securing the drive unit to the printer frame. Carefully pull
the assembly away from the frame.
Reverse these steps to install the process drive unit. Ensure the front bearing of
the accumulator belt assembly is inserted fully into its receiver hole of the printer
frame.

Service Guide

115

Accumulator
belt bracket

Process drive
unit

High voltage
power supply
bracket
Wiring harness
780-5-77

Removing the process drive unit

116

Phaser 780 Color Printer

Waste auger assembly
Caution

Be careful not to spill waste toner from the auger assembly.
Vacuum the auger before removal.

1. Remove the accumulator belt assembly.
2. Remove second bias transfer roller assembly.
3. Remove the paper-feed motor.
4. Remove the fuser drive gear train to access the screw securing the
plastic bracket holding the water auger housing.

5. Remove the low voltage power supply.
6. Remove the two screws securing the accumulator belt rear bracket to
the rear of the printer frame. Remove the bracket.

7. Remove the screw securing the auger drive assembly to the printer
frame.

8. Remove the screw securing the auger tube to the rear of the printer
frame.

9. Remove the screw securing the auger assembly bracket to the rear of the
printer frame.

10. Remove the auger assembly from the printer.
Reverse these steps to install the waste auger assembly.

Service Guide

117

Waste auger
drive assembly

Waste auger
assembly

780-5-64

Removing the waste auger assembly

118

Phaser 780 Color Printer

Accumulator belt assembly
1. Remove the high voltage power supply.
2. Remove the erase lamp rail assembly.
3. Remove the paper feeder.
4. Remove the process drive unit.
5. Remove the auto-density calibration sensor.
6. Reach through the paper feeder cavity and disconnect the wiring
harness from the accumulator belt sensor.

7. Move the waste auger assembly for clearance. Refer to “Waste auger
assembly” on page 117.

8. Remove the two screws securing the accumulator belt assembly bracket
to the rear of the printer frame. Remove the bracket.

Caution

The accumulator belt is easily scratched, be careful when
removing it.

9. Hold on to the front and the rear of the accumulator belt assembly shaft.
Note, for reassembly, the orientation of the spring collar and K-clip.
Push in on the spring loaded collar to release the front of the
accumulator belt assembly drive shaft from the front of the printer
frame.

10. Lift up the accumulator belt assembly; free the two high voltage wires
from the grommet hole at the rear of the frame, and remove the
accumulator belt assembly out of the printer frame.

11. Place the accumulator belt assembly on a clean, flat, and stable work
surface. Do not allow the belt itself to touch any foreign surfaces.
On reassembly, remove the shipping restraints from the front and rear of the new
accumulator belt assembly. Ensure that the front bearing of the accumulator belt
assembly squarely fits into its receiver hole in the frame.

Service Guide

119

Spring loaded
collar
Bearing fits
in hole

Accumulator belt
assembly
Accumulator belt
assembly

780-5-59

Removing the accumulator belt assembly

120

Phaser 780 Color Printer

Accumulator belt cleaner assembly
1. Remove the fuser assembly as described in “Fuser assembly” on
page 125.

2. Open the front cover.
3. Reach through the empty fuser cavity and hold the bottom of the belt
cleaner assembly.

4. Loosen the two screws securing the cleaner support to the printer
frame. Remove the cleaner support while retaining the spring on the
cleaner support.

5. Slide the belt cleaner assembly to the front of the printer and remove the
assembly through the fuser cavity.
Reverse these steps to install the accumulator belt cleaner assembly. Enter
diagnostics and select Reset Accumulator Belt Cleaner Life.

Cleaner support

Accumulator belt
cleaner assembly

780-5-63

Removing the accumulator belt cleaner assembly
Service Guide

121

Second bias transfer roller assembly
1. Remove the fuser assembly as described in “Fuser assembly” on
page 125.

2. Remove the accumulator belt cleaner assembly as described in the topic
“Accumulator belt cleaner assembly” on page 121.

3. Reach through the empty fuser cavity and slide the second bias transfer
roller assembly out of the second bias transfer roller front and rear
brackets and out of the printer.
Reverse these steps to install the second bias transfer roller assembly.

Second bias transfer
roller assembly

780-5-62

Removing the second bias transfer roller assembly

122

Phaser 780 Color Printer

Second bias transfer roller cam assembly
1. Remove the second bias transfer roller assembly as described in
“Second bias transfer roller assembly” on page 122.

2. Remove the second bias transfer roller cam assembly as described in
“Second bias transfer roller cam assembly” on page 123.

3. Remove the waste auger assembly as described in “Waste auger
assembly” on page 117.

4. Remove the three screws securing the second bias transfer roller cam
assembly to the printer frame. Pull the assembly a few inches away
from the rear frame.

5. Disconnect the wiring harness running to the second bias transfer roller
cam assembly.

6. Remove the second bias transfer roller cam assembly.
Reverse these steps to install the second bias transfer roller cam assembly.

Service Guide

123

Wiring harness

Second bias transfer
roller cam assembly

780-5-60

Removing the second bias transfer roller cam assembly

124

Phaser 780 Color Printer

Fuser assembly
1. Turn off the printer and open the top media tray.
2. Remove the screw securing the fuser assembly to the printer frame.
3. Slide the fuser assembly a few inches out of the printer.
4. Lift the end of the fuser assembly and pull the assembly out of the
printer.
To install the fuser assembly in the printer, lift the end of the fuser assembly as
you insert the assembly side rails into the guide wheels inside the printer. Lower
the end of the fuser assembly and slide the assembly into the printer. Reinstall the
screw to secure the fuser assembly to the printer frame.

Fuser assembly
Rear screw

Tray 1

Front
screw
780-18-01

Removing the fuser assembly

Service Guide

125

Fuser drive gear train
1. Remove the fuser unit.
2. Remove the low voltage power supply.
3. Remove the paper feed drive gear train.
4. Remove the wire harness from the paper-feed motor bracket.
5. Remove the screw securing the paper-feed motor bracket to the fuserdrive gear train and remove the bracket.

6. Reach inside the empty fuser assembly cavity and remove the E-ring
securing the fuser drive gear shaft to the auger drive assembly.

7. Remove the five screws securing the fuser-drive gear train to the printer
frame. Remove the gear train.
Reverse these steps to install the fuser drive gear train.

126

Phaser 780 Color Printer

Fuser drive
gear train

E ring

Paper feed
motor bracket

Auger assembly

780-5-74

Removing the fuser-drive gear train

Service Guide

127

Lower exit assembly
1. Remove the left door by pushing in on its front hinge to free it from the
printer.

2. Disconnect the wiring harnesses near the top rear of the lower exit
assembly.

3. Remove the five screws securing the lower exit assembly to the printer
frame.

4. Lift the lower exit assembly to unhook the top of the assembly from the
printer frame. Remove the assembly.

5. Disconnect the wiring harness from the top exit sensor and the wiring
harness from the exit chute switch, both located on the back of the lower
exit assembly.

6. Remove the wires from the wire clips that are molded into the side of
the lower exit assembly.
Reverse these steps to install the lower exit assembly.

128

Phaser 780 Color Printer

Lower exit
assembly

Wiring harness

780-5-68

Removing the lower exit assembly

Service Guide

129

Full stack sensor
1. Open the left door.
2. Remove the screw securing the full stack sensor and its bracket.
Squeeze the four latches securing the full stack sensor to the bracket.

3. Disconnect the sensor’s connector P/J 167
Reverse these steps to install the full stack sensor.

Full stack
sensor

780-5-158

Removing the stack full sensor

130

Phaser 780 Color Printer

Low voltage power supply
1. Remove the rear cover.
2. Disconnect the wiring harness from the top of the low voltage power
supply. All the wiring harnesses plugs are held in place with locking
levers.

3. Disconnect the remaining wiring harnesses from the low voltage power
supply.

4. Release the wiring harness from the wire clip located at the top left of
the low voltage power supply.

5. Remove the four screws securing the low voltage power supply to the
printer frame. Lift and remove the low voltage power supply from the
printer frame.
Reverse these steps to install the low voltage power supply.

Printer
frame
Wiring harness

Low voltage
power supply

780-5-83

Removing the low voltage power supply
Service Guide

131

High voltage power supply
1. Remove the rear cover.
2. Disconnect the wiring harnesses from the bottom of the high voltage
power supply.

3. Disconnect the five high-voltage wiring harness from the high voltage
power supply.

4. Remove the four screws securing the high voltage power supply to the
high voltage power supply brackets. Remove the high voltage power
supply.
Reverse these steps to install the high voltage power supply.

High voltage
power supply

Wiring harness
Removing the high voltage power supply

132

Phaser 780 Color Printer

780-5-84

Image processor
1. Disconnect all interface cables connecting to the image processor.
2. Remove the right cover.
3. Disconnect all wiring harnesses from the image processor.
4. Remove the 10 screws securing the image processor to the image
processor chassis. Pull the image processor away from the chassis,
disconnecting the image processor from the engine control board.

Swap components.

If you are replacing the image processor board,

exchange:
■

The Boot ROM (PLCC)

■

The NVRAM chip (DIP)

■

The Real Time Clock module

The components contains important customer-created parameters. The printer
may not operate correctly without the components being swapped.
Also transfer from the old board to the new board.
■

The RAM DIMMs

■

The PhaserShare card

■

The SCSI card

Image processor

Front plate
Removing the image processor

Service Guide

133

Image processor chassis
1. Remove the image processor fan.
2. Remove the image processor as descried in “Image processor” on
page 133.

3. Loosen, but do not remove, the four screws securing the bottom of the
image processor chassis assembly to the printer frame.

4. Remove the five screws securing the top of the image processor chassis
assembly to the printer frame.

5. Lift the image processor chassis assembly up and off the four loosened
screws located at the bottom of the chassis. Remove the chassis from
the printer frame.
Reverse these steps to install the image processor chassis.

Image processor chassis

Loosen these screws
780-5-91

Removing the image processor chassis

134

Phaser 780 Color Printer

Print engine control board
1. Perform the Life Date: Save Life Count described in “Running built-in
diagnostics” on page 69 to save the information stored in the print
engine control board NVRAM in the image processor board.

2. Remove the image processor chassis.
3. Disconnect the nine wiring harnesses connected to the print engine
control board.

4. Remove the screw securing the ground wire to the print engine control
board. Remove the wire.

5. Remove the three other screws securing the print engine control board
to the printer frame. Remove the board.
Reverse these steps to install the engine control board. Perform the Life Date:
Restore Life Count to restore the counts to the engine control board NVRAM.

Wiring harness

Ground wire

Print engine
control board
780-5-87

Removing the print engine control board
Service Guide

135

136

Phaser 780 Color Printer

FRU List
This topic provides a list of field replaceable units for the Phaser 780 Color Printer.
Changes to Tektronix products are made to accommodate improved components
as they become available. It is important when ordering parts to include the
following information:
■

Component's part number

■

Product type or model number

■

Serial number of the printer

Serial numbering. Particular fields in the serial number indicate the modification
level of the printer, the date of its manufacture and the sequence number of the
printer produced on that day. The serial number is coded as follows:

JLxxDMY

J
L

indicates the headquarter country of the manufacturing company, Japan.

indicates the modification level of the printer, ranging alpha-numerically
from 0 to Z.

xx alpha-numerically indicates the sequence of the printer among the
printers produce on that day of manufacture, ranging from 01 to ZZ
representing
1 to 1296 (the letters I and O are not used).

D alpha-numerically indicates the day of manufacture, ranging
from 1 to X representing 1 to 31 (the letters I and O are not used).
M alpha-numerically indicates the month of manufacture, ranging
from 1 to C representing 1 to 12.
Y numerically indicates the last digit of the year of manufacture, ranging
from 0 to 9.

Service Guide

137

10

6

7a
11

7b
5

3c

4
7c
12

8
3b
2

3a

9

1c
9

1c

1b

9
1b
1a

Printer cabinet FRUs

138

Phaser 780 Color Printer

Z780-5-119

Table 1 Printer cover FRUs
Parts

Part number

1
1a
1b
1c

118-9714-00

2

118-9733-00

3
3a
3b
3c

118-9715-00

4

Serial number
Qty
Effective Discont’d

Name and description

1
2
2

Front cover assembly kit
Front cover
Hinge plate
Front cover strap
Hardware

1

Inner cover (includes 3a and 3b)

1
1
1

Carousel latch kit
Carousel latch lever
Carousel latch spring
Carousel latch assembly

118-9737-00

1

Left lower cover

5

118-9739-00

1

Front LCD panel

6

118-9734-00

1

Top cover and stopper

7
7a
7b
7c

118-9716-00
118-9864-00

1
1
1

Rear cover assembly kit
Toner Filter
Rear cover
Access cover

8

118-9738-00

1

Right cover with shield

9

118-9884-00

1

Front lower cover

10

118-9735-00

1

Stopper

11

118-9736-00

1

Toner filter

12

118-9864-00

1

Access cover

Service Guide

139

1

2
10
3

4

6b

10
9d

7

5
8

9e

6c

6a
6e

9a
9c
9b

7
6g

Paper feeder FRUs

140

6d

Phaser 780 Color Printer

6f
Z780-5-120

Table 2 Paper feeder FRUs
Parts

Part number

1

118-9747-00

1

Size switch board

2

118-9742-00

1

Feed gear

3

118-9743-00

1

Feed spring

4

118-9744-00

1

Feed solenoid

5

118-9717-00

2

Paper pick rollers

1
1
1
1
1
1
1

Turn roller assembly kit
Turn gear pin
Turn arm spring
Turn rear bearing
Turn assembly
Turn gear
Turn roller shaft
Turn front bearing

6

Serial number
Qty
Effective Discont’d

118-9718-00
6a
6b
6c
6d
6e
6f

Name and description

7

118-9983-00

1

Feed roller bearing

8

118-9745-00

1

Turn chute

1
1
1
1
1

Paper empty sensor assembly kit
Empty sensor harness
Empty sensor
Sensor actuator
Sensor bracket
Low paper sensor

1

Tray stopper

9

118-9719-00
9a
9b
9c
9d
9e

10

118-9746-00

Service Guide

141

1

2

5

4
3

780-5-121

Multi-purpose tray cover FRUs

142

Phaser 780 Color Printer

Table 3 Multi-purpose tray cover FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9748-00

1

Multi-purpose tray left (front) cover

2

118-9749-00

1

Multi-purpose tray right (rear) cover

3

118-9751-00

1

Multi-purpose tray/extender

4

118-9750-00

1

Multi-purpose tray holder

5

118-9720-00

1

Multi-purpose tray assembly (items 1
thru 4)

Service Guide

143

10

2
4
7
3

5

8
6
9

1

11

12
13
Multi-purpose tray FRUs

144

Phaser 780 Color Printer

780-5-122

Table 4 Multi-purpose tray FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9763-00

1

Multi-purpose tray pad kit

2

118-9752-00

1

Multi-purpose tray edge sensor

3

118-9754-00

1

Multi-purpose tray paper sensor actuator

4

118-9827-00

1

Multi-purpose tray paper sensor

5

118-9756-00

1

Multi-purpose tray pick-up cam gear

6

118-9757-00

1

Multi-purpose tray cam gear spring

7

118-9758-00

1

Multi-purpose tray pick-up gear

8

118-5759-00

1

Multi-purpose tray pick-up spring

9

118-5760-00

1

Multi-purpose tray pick-up solenoid

10

118-9755-00

2

Multi-purpose pick roller kit

11

118-9752-00

1

Multi-purpose tray long paper sensor

12

118-9762-00

1

Multi-purpose tray gear

13

118-9761-00

1

Multi-purpose tray clutch

Service Guide

145

3

1
2
780-5-123

Paper feeder cover FRUs

146

Phaser 780 Color Printer

Table 5 Paper feeder cover FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9766-00

1

Paper feeder turn chute

2

118-9765-00

1

Paper feeder cover

3

118-9865-00

1

paper feeder assembly

Service Guide

147

3
1
2

5
4a

7
4b

6

780-5-124

Paper feeder FRUs

148

Phaser 780 Color Printer

Table 6 Paper feeder FRUs
Parts

Part number

1

118-9771-00

1

Registration rubber roller

2

118-9768-00

1

Feeder pre-registration roller

3

118-9770-00

1

Registration clutch

118-9721-00

1

Registration spring kit
Rear spring (black)
Front spring (silver)

5

118-9769-00

1

Pre-registration clutch

6

118-9767-00

1

Pre-registration knob

7

118-9752-00

1

Registration sensor

4

Serial number
Qty
Effective Discont’d

4a
4b

Name and description

Service Guide

149

2

1
3

4
5

6

7

780-5-125

Imaging FRUs

150

Phaser 780 Color Printer

Table 7 Imaging FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9774-00

1

Laser unit

2

118-9778-00

1

Erase lamp

3

118-9777-00

1

Auto-density calibration sensor assembly

4

118-9722-00

1

Bias charge roller connector kit with
wiring harness

5

118-9779-00

1

Waste cartridge full sensor

6

118-9780-00

1

Waste cartridge installed sensor

7

118-9781-00

1

Imaging unit connector

Service Guide

151

1

1

2
2

1

2

3
3

4
3

4

4
Developer FRUs

152

Phaser 780 Color Printer

780-5-126

Table 8 Developer FRUs
Parts

Part number

1

118-9782-00

1

Developer assembly, Black

2

118-9783-00

1

Developer assembly, Cyan

3

118-9784-00

1

Developer assembly, Magenta

4

118-9785-00

1

Developer assembly, Yellow

116-0073-00

Serial number
Qty
Effective Discont’d

Name and description

Developer shim kit (1 each of 4 sizes)

Service Guide

153

4c

6

5
4d

4b
4a

3
2

1
780-5-127

Carousel FRUs

154

Phaser 780 Color Printer

Table 9 Carousel FRUs
Parts

Part number

1

118-9787-00

1

Toner cartridge presence sensor

2

118-9724-00

1

Developer contact assembly

3

118-9820-00

1

Carousel knob

1
1
1
1

Carousel assembly kit
Carousel knob
Carousel front bearing
Carousel frame
Carousel rear bearing

4

Serial number
Qty
Effective Discont’d

118-9723-00
4a
4b
4c
4d

Name and description

5

118-9788-00

1

New toner cartridge sensor

6

118-9786-00

1

Carousel home sensor

Service Guide

155

5

8d
6
8a

7

8b
8c

2b

3

2a

1
Accumulator belt assembly FRUs

156

Phaser 780 Color Printer

780-5-128

Table 10 Accumulator belt assembly FRUs
Parts

Part number

1

118-9790-00

2

Serial number
Qty
Effective Discont’d
1

Tension lever

1
1

Belt cleaning assembly kit
Cleaner support assembly
Belt cleaner

118-9726-00
2a
2b

Name and description

3

118-9791-00

1

Second bias transfer roller cam
assembly

5

118-9789-00

1

Accumulator belt assembly

6

118-9793-00

1

Waste auger assembly

7

118-9792-00

1

Transfer roller cam solenoid

1
1
1
1

Second bias transfer roller assembly kit
Second bias transfer bracket
Second bias transfer bearing-6
Second bias transfer bearing-4
Second bias roller transfer assembly

8

118-9725-00
8a
8b
8c
8d

Service Guide

157

1

4

2

3

780-5-129

Fuser assembly FRUs

158

Phaser 780 Color Printer

Table 11 Fuser assembly FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9886-01
118-9887-01

1
1

Fuser, 110 VAC
Fuser, 220 VAC

2

016-1866-00

1

Fuser roll cartridge

3

118-9986-00

1

Fuser tray release lever

4

118-9727-00
118-9728-00

1

Fuser assembly 110V
Fuser assembly 220V

Service Guide

159

1

3
2

3
3
3
3

780-5-130

Paper exit FRUs

160

Phaser 780 Color Printer

Table 12 Paper exit FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9798-00

1

Lower exit assembly

2

118-9799-00

1

Upper exit assembly

3

118-9800-00

1

Exit tray assembly

Service Guide

161

1e
1d

1b
1e

1c
1b
1f
5

1a
1a
1a

1c
1b

1a

2
3

1a

1a
1a
1a
4
780-5-131

Paper exit FRUs

162

Phaser 780 Color Printer

Table 13 Paper exit FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

1

118-9729-00

1

Exit upper roller kit
Exit idler gear
Exit spur gear
Exit rear bearing
Exit-3 roller
Exit front bearing
Exit-2 roller

2

118-9802-00

1

Exit door switch

3

118-9801-00

1

Media exit sensor with flag

4

118-9803-00

1

Fuser fan

5

116-0050-00

1

Full stack sensor

1a
1b
1c
1d
1e
1f

Name and description

Service Guide

163

1

2

3

5
4

6
7a
9

7b

7d
7c
Drive FRUs

164

Phaser 780 Color Printer

7c

8

780-5-132

Table 14 Drive FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

1

118-9804-00

1

Paper feed drive assembly

2

118-9806-00

1

Process drive assembly

3

Name and description

Process motor (part of process drive
assembly)

4

118-9809-00

1

Carousel motor board

5

118-9810-00

1

Toner/developer dispense motor

6

118-9811-00

1

Developer clutch

7

118-9730-00

Paper feed motor assembly kit
Paper feed motor support
Paper feed motor
Harness clamp
Paper feed bracket

8

118-9805-00

Fuser drive assembly

9

118-9808-00

Carousel motor

7a
7b
7c
7d

Service Guide

165

Part of Carousel
FRU Part 2

Part of Imaging
FRU Part 4
1

2a

3
2b
A

4

5
6
A
780-5-133

Electronic (rear) FRUs

166

Phaser 780 Color Printer

Table 15 Electronic (rear) FRUs
Parts

Part number

1

118-9873-00

2

Serial number
Qty
Effective Discont’d
1

High voltage power supply board

1
1

Developer fan kit
Developer fan
Developer fan duct

118-9731-00
2a
2b

Name and description

3

118-9816-00

1

Top cover switch

4

118-9817-00

1

Fuser connector, Main

5

119-5871-00
119-5872-00

1
1

Low voltage power supply, 110 VAC
Low voltage power supply, 220 VAC

6

118-9819-00

Main harness, DC

Service Guide

167

6
3

5

4
2

7
10

8

9

1
780-5-134

Electronics (front) FRUs

168

Phaser 780 Color Printer

Table 16 Electronic (front) FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9822-00

1

Front cover switch, right

2

118-9821-00

1

Front cover switch, left

3

118-9815-00

1

Exit connector-8

4

118-9814-00

1

Exit connector -4

5

118-9824-00

1

Video harness

6

118-9825-00

1

Laser unit harness

7

118-9796-00

1

Engine control board

8

118-9823-00

1

Paper feeder harness

9

118-9863-00

1

Environmental sensor

10

163-1283-00

1

Print engine NVRAM chip

Service Guide

169

1

11
10

8
7
9
6

2
3
Image processor FRUs

170

Phaser 780 Color Printer

12
4

5
780-5-135

Table 17 Image processor FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9826-00

1

Image processor fan

2

118-9885-00

1

Front panel harness

3

671-4303-80

1

Image processor board

4

156-4759-00
156-4765-00
156-4780-00

1

RAM DIMM, 32 Mbytes
RAM DIMM, 64 Mbyte
RAM DIMM, 128 Mbyte

5

671-4759-00
671-4687-00
671-4688-00
671-4686-00

1
1
1
1

Font ROM SIMM, Kanji
Font ROM SIMM, Simplified Chinese
Font ROM SIMM, Traditional Chinese
Font ROM SIMM, Korean

6

671-4672-51
671-4673-51

PostScript Code SIMM, Base (v2.86)
PostScript Code SIMM, Graphics and
Plus (v2.86)

7

671-4306-50

SCSI riser board

8

671-3994-00
671-3932-00
671-4034-00
386-6998-00
213-1090-00

1
1
1
1
2

Ethernet 100baseT Network card
TokenRing card
LocalTalk card
Blank panel, net card
Screws, 4-40 x .312

9

119-6032-00

1

CPU Fan

10

650-3886-01

1

Dallas Real Time Clock

11

156-4768-00

1

NVRAM

12

163-1148-00

1

Boot ROM/Product ID

Service Guide

171

3

2

4
5

1

6

6

8

8
8

1
8

7

780-5-136

Optional lower feeder cabinet FRUs

172

Phaser 780 Color Printer

Table 18 Optional lower feeder cabinet FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9923-00

1

Lower feeder front cover

2

118-9926-00

1

Lower feeder left cover

3

118-9924-00

1

Lower feeder rear cover

4

118-9925-00

1

Lower feeder harness cover

5

118-9928-00

1

Lower feeder chute assembly

6

118-9929-00

1

Lower feeder chute support

7

118-9927-00

1

Lower feeder right cover

8

118-9930-00

1

Lower feeder caster

Service Guide

173

3
4
D
2

5

1
6
1

A

1

B
D
9
C

10: Items 1 thru 9

A
8

B
7
7
8

C

Optional Feeder FRUs

174

Phaser 780 Color Printer

7

780-5-137

Table 19 Optional feeder FRUs
Parts

Part number

Serial number
Qty
Effective Discont’d

Name and description

1

118-9931-00

1

Lower feeder assembly

2

118-9934-00

1

Lower feeder gear assembly

3

118-9933-00

1

Lower feeder motor

4

118-9936-00

1

Lower feeder interface harness

5

118-9935-00

1

Lower feeder circuit board

6

118-9747-00

7

118-9932-00

1

Lower feeder turn-in chute

8

118-9985-00

1

Tray spacer

9

118-9802-00

1

Lower feeder chute switch

10

436-0367-00

1

Lower tray assembly (optional feeder)

Lower feeder paper size sensor

Service Guide

175

Supplies and accessories
Table 20 Supplies and accessories
Parts

176

Part number

Serial number
Effective Discont’d

Qty

Name and description

016-1678-00

Toner Cartridge, Black

016-1679-00

Toner Cartridge, Cyan

016-1680-00

Toner Cartridge, Magenta

016-1681-00

Toner Cartridge, Yellow

016-1864-00

Imaging Unit Cartridge

016-1865-00

Imaging Unit Waste Cartridge

016-1866-00

Standard Fuser Roll Cartridge

016-1717-00

High Duty Fuser Roll Cartridge

016-1369-00

A4 Size Paper, 500 Sheets

016-1697-00

Tab Plus Glossy, 100#, 50 Sheets

016-1699-00

Plain Paper,24#,b,500 Sheets

016-1700-00

Plain Paper,24#,a3,500 Sheets

016-1701-00

Transparency, A, 50 Sheets

016-1702-00

Transparency, A4, 50 Sheets

016-1703-00

Paper, Image Transfer, B, 100 Sheets

016-1704-00

Paper, Glossy, A, 100#, 100 Sheets

016-1705-00

Paper, Glossy, A4, 100#, 100 Sheets

016-1706-00

Transparency, Tab Extra, 50 Sheets

016-1709-00

Paper, Tab Plus, 24#, 500 Sheets

016-1718-00

Paper, Glossy Coated, B, 100 #, 50
sheets

063-3039-00

CD, ROM, English

063-3039-10

CD, ROM, French

063-3039-20

CD, ROM, Italian

063-3039-30

CD, ROM, German

063-3039-40

CD, ROM, Spanish

063-3039-70

CD, ROM, Simplified Chinese

063-3039-80

CD, ROM, Traditional Chinese

063-3039-90

CD, ROM, Korean

063-3040-00

User Guide, English

063-3040-10

User Guide, French

Phaser 780 Color Printer

Table 20 Supplies and accessories
Parts

Part number

Serial number
Effective Discont’d

Qty

Name and description

063-3040-20

User Guide, Italian

063-3040-30

User Guide, German

063-3040-40

User Guide, Spanish

063-3040-05

User Guide, Russian

063-3041-00

Quick Reference Guide, Service

063-3094-00

Setup Guide, English

063-3094-10

Setup Guide, French

063-3094-20

Setup Guide, Italian

063-3094-30

Setup Guide, German

063-3094-40

Setup Guide, Spanish

063-3094-05

Setup Guide, Russian

063-3116-00

Phasershare Setup Guide

063-3116-10

Phasershare Setup Guide, French

063-3116-20

Phasershare Setup Guide, Italian

063-3116-30

Phasershare Setup Guide, German

063-3116-40

Phasershare Setup Guide, Spanish

063-3126-00

CD, Adobe Type Manager

063-3181-00

CD, Phaser Match, Color Match

070-9925-00

Advanced Features & Troubleshooting,
English

161-0066-00

Power Cord, 115v

161-0066-09

Power Cord, 220v

161-0066-10

Power Cord, U.K.

161-0066-11

Power Cord, Aust.

161-0154-00

Power Cord, Swiss

161-0240-00

Power Cord, Danish

436-0366-00

Universal Size Paper Tray (Std)

436-0368-00

Labels & Transparency Tray

013-0297-00

Cable, Adapter, SCSI 1 TO SCSI 2

118-9921-00

Hardware Kit

116-0073-00

Developer shim kit (4 sets of 3 sizes)

003-0619-00

I.C. Extractor, SCSI Board removal tool

Service Guide

177

Table 20 Supplies and accessories
Parts

178

Part number

Serial number
Effective Discont’d

Qty

Name and description

003-1633-00

IC PLCC Extractor Tool

065-0574-00

Repackaging Kit

650-3572-01

Rebanding Kit

650-3971-00

Recycle kit for developer assemblies,
California only

003-1496-00
003-1497-00

Vacuum cleaner, 110/115 VAC
Vacuum cleaner, 220/240 VAC

003-1498-00

Vacuum cleaner filter, Type 2, 3M

004-4845-00

Shipping Box

003-0602-00

#1 Pozidrive screwdriver tip

006-7971-00

Imaging unit lightshield

Phaser 780 Color Printer

Test Prints
This topic illustrates the test prints produced by the print engine. It also
illustrates a number of defective prints and the reason for the defects. The topic
“Printing and print quality problems” on page 43 discusses solutions to the
problems shown in this appendix.
Consumables Print consists of four 25% tint primary color bands and “gas
gauges” for each consumable. Service Print 1 prints out four 25% tint full page
fills, each page one primary color.
1

Replace Magenta Toner Cartridge
Press i for information

Phaser 780 Color Printer
®

Toner
Life Remaining

25 %

Your average coverage/page: 20.0%

Black
0%

50%

Life Remaining

100%

33 %

Your average coverage/page: 40.0%

Magenta
0%

50%

Life Remaining

100%

50 %

Your average coverage/page: 50.0%

Cyan
0%

50%

Life Remaining

2

Help Pages
Consumable Pages

100%

75 %

Your average coverage/page: 30.0%

Yellow
0%

Print

Fuser Roll

Life Remaining
0%

50%

100%

10 %
50%

Imaging Unit

Imaging Unit

Fuser Roll

Life Remaining
0%

Toner

100%

Count (Pages): 1061

10 %
50%

100%

Count (Pages): 1061
S/N: 00:00:00:00:00:00
Avg. toner coverage/color: 20%
Date installed: 11/1/98

3

Help Pages
Service Print 1

Print

Service Print 1
Service Print 1
Black

Cyan

Magenta

Yellow

Service Guide

179

Interpreting Service Print 2
3

4

Service print 2 should always be printed on
B-size paper.

1
4

1. Color registration. The thin lines should

6

2.
3.
4.

4

5

5.
6.

not be above or below the think line.
Preferable they should be centered.
Blur. The lines should be crisp and
sharp with no “fuzzy” appearance.
Ghosting. No ghost images of the
square patterns should appear in the
gray bar below the square patterns.
Uniform RGB. The secondary color
squares should be uniformly colored with
no mottling.
Resolutions. The thin lines should be
fully separated from each other
Text. The text should be sharp with no
discernible voids.

2

4

4

1

Interpreting Service Print 3
1

Service print 3 should always be printed on
B-size paper.

2

1. Skew. The difference between the

LEAD EDGE

values measured at each corner of the
leading edge of the print should be no
greater than +/- 2 mm.
2. Leading edge. The value measure from
the leading edge to the indicated line
should be 14.9 mm (+/-2 mm).
3. Side edge. The value measure from the
side edge to the center should be
148.5 mm (+/-2.5 mm). (When the print
is accurately folded in half lengthwise, the
center line should be in the center of the
crease.)

3

TRAIL EDGE

3041-35

180

Phaser 780 Color Printer

Interpreting Service Print 4
Service print 2 should always be printed on
B-size paper. The print reveals repeating
defects that can be traced back to defects on
the printers belts, drum or rollers.

1. Look for repeating defects inline down
the print.
Refer to the topic “Repetitive mark
appears on each print” on page 56. It
discusses caused of repeating spots
based on the distance between the spots.

3041-36

Interpreting Sevice Print 5: Yellow
Calibration Page
Service print 5 is a 100% yellow solid fill.
Refer to the topic “Printing and print quality
problems” on page 43 for solution to any
print problems detected. Look for voids,
repeating spots and banding. This solid fill is
also useful for flushing out defective yellow
toner.

Service Guide

181

Interpreting Sevice Print 6: Magenta
Calibration Page
Service print 6 is a 100% magenta solid fill.
Refer to the topic “Printing and print quality
problems” on page 43 for solution to any
print problems detected. Look for voids,
repeating spots and banding. This solid fill is
also useful for flushing out defective
magenta toner.

Interpreting Sevice Print 7: Cyan Calibration
Page
Service print 7 is a 100% cyan solid fill.
Refer to the topic “Printing and print quality
problems” on page 43 for solution to any
print problems detected. Look for voids,
repeating spots and banding. This solid fill is
also useful for flushing out defective cyan
toner.

182

Phaser 780 Color Printer

Interpreting Sevice Print 8: Black Calibration
Page
Service print 8 is a 100% black solid fill.
Refer to the topic “Printing and print quality
problems” on page 43 for solution to any
print problems detected. Look for voids,
repeating spots and banding. This solid fill is
also useful for flushing out defective black
toner.

Service Print 9: Fuser Cleaning Page
Service print 9 is a blank sheet of paper
used to clean the fuser rollers as well as test
the operation of the paper feed components.

Service Guide

183

184

Phaser 780 Color Printer

Wiring Diagrams
J 35

J 16

LOW VOLTAGE
POWER SUPPLY
J 32
J 33

(BCR)
BIAS CHARGE
ROLLER

J 79

J 195
J 21

J 12

J 70

J 97

J 72

J 191 J 192
RIGHT

J 193

J 42

HIGH VOLTAGE POWER SUPPLY

J 41

BCR

J 196

SECOND
BTR

J 194

J 19
J 75

J 19

J 71

J 13

J 77

J 14

J 78

J 197

LEFT

J 20

J 93

J 122 Laser
Scanner
J 121

LASER
SCANNER

ACCUMULATOR
BELT ASSY

J 98

SECOND SECOND
BTR
BTR
ASSY

(BTR)
BIAS TRANSFER
ROLLER

J 99

J 123
J 18

J 73

J 124 Start of Scan

J 95

(ADC)
AUTO-DENSITY
CALIBRATION

J 74
J 17

J 94
J 86

PAPER FINDER

J 80
J 18
J 76

J 116

J 20

J 102

J 19

J 16
ENGINE
CONTROL
BOARD

J 204

MUTI-PURPOSE

J 205

MUTI-PURPOSE

J 206

J 22
J 84

J 85
MUTI-PURPOSE

J 203

MUTI-PURPOSE

J 201

J 103
EMPTY

J 107

J 101

J 20
MUTI-PURPOSE

J 106
J 104

J 58

J 168 TONER

J 56
MUTI-PURPOSE

J 83
J 105

J 19

J 89

CAROUSEL

J 90

J 88

J 19

J 87
J 161

J 81

J 62

J 117

J 17

J 91

J 94

J 92

J 82

J 20
J 18

J 55 TONER

J 16

J 245 CAROUSEL
BOARD

J 19

J 63

BTR
CAM SOLENOID

J 17

J 57

ACCUMULATOR BELT
SENSOR

J 246
J 247

CAROUSEL

J 113

J 202

J 165

J 161

J 17

J 50 PAPER FEED

J 49

J 52

J 51

J 166
J 11
J 167

J 163

IMAGE
PROCESSOR

J 310
J 314

J 111

J 19

J 317 FRONT PANEL
IMAGE
PROCESSOR
3041-09

Print engine wiring diagram

Service Guide

1

Plug/Jack Locations - 1
P/J

Map & Coordinates

Connected to...

Other end connected to...

10

Map 2-D205

Engine control board

--

11

Map 2-E205

Engine control board

Image processor board

12

Map 2-D205

Engine control board

Low voltage power supply P/J33

13

Map 2-D205

Engine control board

Laser Diode board P/J122

14

Map 2-D204

Engine control board

Laser Unit P/J121, P/J123, P/J124

16

Map 2-D204

Engine control board

CRUM

17

Map 2-E204

Engine control board

Auto-density calibration Sensor P/J81
Erase Lamp P/J86

18

Map 2-E203

Engine control board

Waste Toner Sensor P/J88
Toner Box Sensor P/J83

19

Map 2-F203

Engine control board

Fuser Assembly P/J71

20

Map 2-F204

Engine control board

Paper feeder P/J91

21

Map 2-F204

Engine control board

Low voltage power supply P/J32

22

Map 2-C204

Communications Assembly

Engine control board P/J18

22A

Map 2-C204

P/J22

Engine control board P/J16

32

Map 6-D609

Low voltage power supply

Engine control board P/J21

33

Map 6-D610

Low voltage power supply

Engine control board P/J12

35

Map 6-G609

Low voltage power supply

Fuser Assembly P/J71

41

Map 6-C609

High voltage power supply

Low voltage power supply P/J32

42

Map 6-C609

High voltage power supply

Engine control board P/J16

49 CN1

Map 6-E609

Paper feed Motor

Low voltage power supply P/J32

50 CN2

Map 6-608

Paper feed Motor

Engine control board P/J17

186

Phaser 780 Color Printer

Plug/Jack Locations - 2
P/J

Map & Coordinates

Connected to...

Other end connected to...

CN3

Map 6-E609

Mounted on Paper feed motor board

--

CN4

Map 6-E608

Mounted on Paper feed motor board

--

51

Map 6-D608

Process Motor

Low voltage power supply P/J32

52

Map 6-D607

Process Motor

Engine control board P/J17

55

Map 7-E708

Dispense Motor

Engine control board P/J18
Engine control board P/J19

56

Map 7-F708

Developer Clutch

56A

Map 7-F708

P/J56

Engine control board P/J19

57

Map 5-C509

Accumulator belt Sensor

Engine control board P/J17

58

Map 7-F708

Carousel Sensor

Engine control board P/J19

62

Map 8-E812

Cleaner Cam Solenoid

Fuser Tray Assembly P/J71

62A

Map 8-E812

Cleaner Cam Solenoid P/J62

Fuser Tray Assembly P/J71

63

Map 7-C710

BTR Cam Solenoid

Engine control board P/J19

63A

Map 7-C710

P/J63

Engine control board P/J19

68

Map 6-B610

--

Optional high capacity feeder

68A

Map 6-B610

P/J68

Option high capacity feeder

69A

Map 8-H813

Option high capacity feeder

--

69B

Map 8-H813

--

Option high capacity feeder

70

Map 7-F711

Fuser Assembly P/J71

Low voltage power supply P/J32

71

Map 7-F710

Fuser Assembly

P/J70

71A

Map 7-F710

Fuser Tray Assembly P/J71

Engine control board P/J18

72A

Map 8-G812

P/J72B

Fuser Assembly P/J71

72B

Map 8-G812

P/J72A

Temperature Sensor Assembly

73

Map 8-I812

Oil Cam Solenoid

P/J73A

73A

Map 8-I812

P/J73 Oil Cam Solenoid

Fuser Tray Assembly P/J71

74

Map 8-I813

Exchange Solenoid

P/J74A

Service Guide

18

Plug/Jack Locations - 3
P/J

Map & Coordinates

Connected to...

Other end connected to...

74A

Map 8-I813

P/J74

Fuser tray assembly P/J71

75

Map 8-H807

Fuser exit sensor

Fuser assembly P/J72B
Fuser assembly P/J76A

76

Map 8-F813

P/J117 fuser entry sensor

76A

Map 8-F813

P/J76

Fuser tray assembly P/J71

77

Map 8-G808

CRU switch assembly

Fuser assembly P/J77A

77A

Map 8-G808

P/J77

Fuser assembly P/J71

78A

Map 8-I813

P/J78B

Fuser assembly P/J71

78B

Map 8-I813

P/J78A

Loop

79

Map 8-F812

Pressure roller heat rod

Fuser assembly P/J71

80

Map 8-D813

Fuser chute fan

Fuser tray assembly P/J80A

80A

Map 8-D813

P/J80

Fuser tray assembly P/J71

81

Map 1-C110

Auto-density calibration sensor
assembly

P/J81A

81A

Map 1-C110

P/J81

Engine control board P/J17
P/J82A

82

Map 6-G608

Developer Fan

82A

Map 6-G608

P/J82A

Engine control board P/J17

83

Map 1-G106

Toner box sensor

P/J83A

83A

Map 1-G106

P/J83

P/J116

84

Map 1-I107

CRUM assembly P/J85

P/J84A

84A

Map 1-I107

P/J84A

Engine control board P/J16

85

Map 1-H107

CRUM assembly

P/J84

86

Map 1-I105

Erase lamp

P/J86A

86A

Map 1-I105

P/J86A

Engine control board P/J17

87

Map 5-I506

Used cartridge sensor

Engine control board P/J17

88

Map 1-F106

Waste toner sensor

P/J116

89

Map 8-D805

Cartridge sensor P/J168

P/J89A

89A

Map 8-D805

P/J89

P/J161B

188

Phaser 780 Color Printer

Plug/Jack Locations - 4
P/J

Map & Coordinates

Connected to...

Other end connected to...

90A

Map 4-G409

P/J90B

Paper feeder P/J91

90B

Map 4-G409

P/J90A

Loop

91

Map 2-D211

Paper feeder

Engine control board P/J20

Map 4-E408
92A

Map 4-E409

Multi-purpose tray assembly P/J92B

Paper feeder P/J91

92B

Map 4-E409

Multi-purpose tray assembly

Paper feeder P/J92A

93

Map 4-D408

Registration sensor

Paper feeder P/J91

94

Map 4-F408

Registration clutch

P/J94A

94A

Map 4-F408

P/J94

Paper feeder P/J110B & P/J115

95

Map 4-G408

Pre-Registration clutch

P/J95A

95A

Map 4-G408

P/J95

Paper feeder P/J110B & P/J115

97

Map 2-F204

Paper feeder P/J 91

Front cover switch R P/J191 & P/J70

98

Map 4-D409

Front OHP sensor

Paper feeder P/J91

99

Map 4-E408

Rear OHP sensor

Paper feeder P/J91

101

Map 2-D212

Tray no paper sensor P/J107

P/J101A

101A

Map 2-D212

P/J101

Engine control board P/J20
Engine control board P/J19

102

Map 7-D711

Size Switch assembly

103A

Map 2-F206

P./J103B

Engine control board P/J19

103B

Map 2-F206

Feed solenoid

P/J103A

104

Map 2-D212

P/J104A

Terminated

104A

Map 2-D212

P/J104

Engine control board P/J20
P/J105A

105

Map 2-D205

Environment sensor

105A

Map 2-D205

P/J105

Engine control board P/J20

106

Map 2-E211

Low Paper sensor

P/J106A

106A

Map 2-E211

P/J106

Engine control board P/J20

Service Guide

18

Plug/Jack Locations - 5
P/J

Map & Coordinates

Connected to...

Other end connected to...

107

Map 2-E213

Tray no paper sensor

P/J 101

109

Map 4-D409

Registration brake clutch

P/J109A

109A

Map 4-D409

P/J109

Paper feeder P/J91

110A

Map 4-G408

P/J110B

Paper feeder P/J91

110B

Map 4-G408

P/J94A, P/J95A, & P/J115

P/J110A

111A

Map 7-G70

P/J111B

Engine control board P/J17

Map 8-D805
111B

Map 8-D806

P/J111A

Fuser Fan

113A

Map 4-E409

Multi-purpose tray assembly P/J113B

Paper feeder P/J91

113B

Map 4-E409

P/J113A

Multi-purpose tray short no paper sensor P/J203
Multi-purpose tray clutch P/J202A-P/J202B
Pick up solenoid P/J201A-P/J202B

115

Map 4-H408

P/J94A & P/J95A

Terminated

116

Map 1-H106

P/J83A

P/J116A

Waste toner sensor P/J88
116A

Map 1-H106

P/J116

Engine control board P/J18

117

Map 5-D507

Fuser In Sensor

P/J76

121

Map 5-D507

Laser diode assembly

Engine control board P/J14

122

Map 5-D506

Laser diode assembly

Engine control board P/J13

123

Map 5-E506

Laser unit

Engine control board P/J14

124

Map 5-C506

Star-of-scan sensor

Engine control board P/J14

131

Map 6-B610

Option connection

not on schematic

131A

Map 6-B610

Option connection

not on schematic

132

Map 6-B610

Option connection

not on schematic

132A

Map 6-B610

Option connection

not on schematic

161A

Map 7-G707

P/J161B

Engine control board P/J17

P/J196

Map 8-D805

190

Phaser 780 Color Printer

Plug/Jack Locations - 6
P/J

Map & Coordinates

Connected to...

Other end connected to...

161B

Map 8-D805

P/J161A

Top Exit sensor P/J165

163A

Map 7-G707

P/J163B

Engine control board P/J17

163B

Map 8-D805

P/J163A

Full Stack sensor P/J167

165

Map 8-F804

Top exit sensor

P/J161B

166

Map 8-E804

Exit chute switch

P/J161B

167

Map 8-G802

Full stack sensor

P/J163B

168

Map 8-J802

Cartridge sensor

P/J89

191

Map 1-E109

Right front cover switch

P/J97

192

Map 1-E109

Right front cover switch

P/J33

193

Map 1-E109

Right front cover switch

P/J33

194

Map 1-E109

Right front cover switch

P/J195

195

Map 6-H607

Top cover switch

P/J195A

195A

Map 6-H607

P/J195

P/J194

196

Map 2-F203

Laser diode assembly P/J121

P/J195

197

Map 5-H506

Left front cover switch

P/J197A

197A

Map 5-H506

P/J197

Engine control board P/J19

201A

Map 4-I408

P/J201B

Multi-purpose tray assembly P/J113B

201B

Map 4-I408

Pick-up solenoid

P/J201A

202A

Map 4-H408

P/J202B

Multi-purpose tray assembly P/J113B

202B

Map 4-H408

Multi-purpose tray pick-up solenoid

P/J201A

203

Map 4-G409

Multi-purpose tray short no paper
sensor

Multi-purpose tray assembly P/J 113B

204

Map 4-G408

Multi-purpose tray edge sensor

Multi-purpose tray assembly P/J92B

205

Map 4-H409

Multi-purpose tray OHP sensor

Multi-purpose tray assembly P/J92B

Exit Chute switch P/J166
Map 8-D805

P/J196
Low voltage power supply P/J33

P/J207
P/J207

Service Guide

19

Plug/Jack Locations - 7
P/J

Map & Coordinates

Connected to ...

Other end connected to ...

206

Map 4-G409

Multi-purpose tray long no paper
sensor

Multi-purpose tray Assembly P/J92B

207

Map 4-F409

Multi-purpose tray assembly P/J92B

P/J204

P/J207
P/J205
P/J206

245

Map 6-F608

Carousel motor board

Engine control board P/J16

246

Map 6-F607

Carousel motor board

Low voltage power supply P/J32

247

Map 6-E607

Carousel motor board

Carousel Motor

F421

Map 5-D508

Bias charge roller connector

High voltage power supply P/J-A

F422

Map 1-B108

Developer contact assembly

High voltage power supply P/J-C

F423

Map 5-D511

DTS Plate

High voltage power supply P/J-G

F791

Map 8-F807

Pressure roller heat rod

Heat roller heat rod

A

Map 6-B606

High voltage power supply

P/J F421

C

Map 6-C607

High voltage power supply

P/J F422

D

Map 6-B609

High voltage power supply

First bias transfer roller bias plate

F

Map 6-B608

High voltage power supply

Second bias transfer roller contact plate

G

Map 6-B608

High voltage power supply

P/J F423

T1

Map 8-G811

Heat roller heat rod

T2

Map 8-I806

Pressure roller heat rod

T3

Map 5-D510

First bias transfer roller bias plate

T4

Map 5-E510

Second bias transfer roller contact
plate

T5

Map 8-I806

Not on schematic

310

Map 3-F306

Image processor board

Front panel P/J317

314

Map 3-G306

Image processor board

Image processor fan

317

Map 3-C306

Front panel

Image processor board P/J314

192

Phaser 780 Color Printer

The following illustrations detail the proper means of routing and dressing printer wiring. Incorrect wiring dressing can result in wires pinched by cabinet panels or damaged
by moving parts of the printer.

A

B

C

D

E

F

G

H

I

J

K

L

101

102

83, 83A
103

88

116, 116A
86, 86A

104

85
F422

105

106

84, 84A

107

108

191
109

193
194

110

192
111

112

81, 81A

113

114

115

3041-10

Map 1 – Wiring routing at the top and front of the printer

Service Guide

19

A

B

C

D

201

202

17
14

E

F

G

H

18

I

J

K

L

196

16

19
20

22, 22A

97

203

21
204

11
205

105, 105A

10

103, 103A

206

207

208

13

209

12
106, 106A

210

91

211

101, 101A
212

104, 104A
213

214

107

215

3041-11

Map 2 – Wire routing around the engine control board
194

Phaser 780 Color Printer

A

B

C

D

E

F

G

H

I

J

K

L

301

302

317

310

303

304

305

310
306

307

308

309

310

311

312

313

314

315
3041-12

Map 3 – Wiring routing around the image processor board
Service Guide

19

.

A

B

C

D

E

F

G

H

I

J

K

L

401

91
94, 94A

402

110A, 110B
403

95, 95A
404

204
405

115

406

407

408

409

201A, 201B

410

411

412

413

202A, 202B

93
98

99

109, 109A

205

113A, 113B

206

92A, 92B
414

207

90A, 90B
203

415
3041-13

Map 4 – Wiring routing around the paper feeder
196

Phaser 780 Color Printer

A

B

C

D

E

F

G

H

I

J

K

L

501

502

122
124

503

121

123
197, 197A

F421

87

504

505

506

507

508

509

510

511

512

57
513

T3
F423

514

T4

515
3041-14

Map 5 – Wire routing around the laser scanner and high voltage power supply
Service Guide

19

A

B

C

D

E

F

G

H

I

J

K

L

601

246

247

245

602

195, 195A
82, 82A

52
51

603

C
604

A

605

606

G

607

F
608

609

610

D
42
68,
68A
(CN4)

611

612

613

35
132, 132A
50(CN2)

131, 131A
103A

49(CN1)

33
41

32

(CN3)

614

615
3041-15

Map 6 – Wire routing at the rear of the printer
198

Phaser 780 Color Printer

A

B

C

D

E

F

G

H

I

J

K

L

701

58

702

55
703

704

705

706

161A
707

163A
111A

708

709

710

711

712

63, 63A
56.56A

713

102
714

71, 71A

35
70

715
3041-16

Map 7 – Wire routing around the power supply
Service Guide

19

A

C

D

E

161A, 161B

801

802

B

89,
89A

163A,
163B

F

G

H

I

J

K

L

166
165

803

168
117

804

T5
805

T2
806

807

75
F791

808

77, 77A
809

810

71

111A,
111B

73,
73A

T1
811

62, 62A
812

80, 80A
813

79
72A, 72B

814

76, 76A

74,
74A
78A,
78B
69A,
69B

815
3041-17

Map 8 – Wire routing around the fuser
200

Phaser 780 Color Printer

ENGINE
CONTROL
BOARD

LOW VOLTAGE POWER SUPPLY

PAPER FEEDER

13
14
15

LASER UNIT

3041-19

Wiring 1 – Low voltage power supply, laser unit, and interlock switches

Service Guide

20

3041-20

Wiring 2 – Engine control board, auto-density calibration sensor, erase lamp, waste toner sensor
202

Phaser 780 Color Printer

ENGINE
CONTROL
BOARD

LOW
VOLTAGE
POWER
SUPPLY

HIGH VOLTAGE POWER SUPPLY

7
6

BIAS
CHARGE
ROLLER
CONNECTOR
ASSY

2ND BIAS TRANSFER
ROLLER CAM ASSY

FIRST
BIAS TRANSFER
ROLLER
BIAS PLATE

DEVELOPER ASSY

FIRST
BIAS
TRANSFER
ROLLER

ACCUMULATOR BELT ASSY
SECOND
BIAS
TRANSFER
ROLLER
ASSY

SECOND
BIAS
TRANSFER
ROLLER

3041-21

Wiring 3 – Low voltage power supply, engine control board, high-voltage power supply and imaging components
Service Guide

20

ENGINE CONTROL
BOARD

CAROUSEL SENSOR

CAROUSEL HOME SENSED(H) 5VDC

TONER DISPENSE
MOTOR ASSY

TONER DISPENSE MOTOR ON(L) 24VDC

3041-22

Wiring 4 – Engine control board, used cartridge sensor, cartridge sensor, carousel sensor, developer clutch, developer fan, toner dispense motor
204

Phaser 780 Color Printer

ENGINE
CONTROL
BOARD

CAROUSEL MOTOR
BOARD

CAROUSEL MOTOR
ASSY

CAROUSEL MOTOR HOLD (L) 5VDC
CAROUSEL MOTOR ON (L) 5VDC
CAROUSEL MOTOR CLOCK

LOW VOLTAGE
POWER SUPPLY

3041-23

Wiring 5 – Engine control board, low voltage power supply, carousel motor board, rotary motor

Service Guide

20

ENGINE
CONTROL
BOARD

BIAS TRANSFER ROLLER
CAM SOLENOID

ACCUMULATOR SENSOR

PAPER FEEDER

LOW VOLTAGE
POWER SUPPLY

3041-24

Wiring 6 – Engine control board, low voltage power supply, bias transfer roller cam solenoid accumulator belt sensor, paper feeder motor, process motor
206

Phaser 780 Color Printer

LOW VOLTAGE POWER SUPPLY
PRESSURE
ROLLER

HEAT ROLLER

ENGINE
CONTROL
BOARD

3041-25

Wiring 7 – Engine control board, low voltage power supply, fuser, oil roll assembly
Service Guide

20

ENGINE
CONTROL
BOARD

3041-26

Wiring 8 – Engine control board, fuser assembly, environment sensor
208

Phaser 780 Color Printer

ENGINE
CONTROL
BOARD

PAPER SIZE SWITCH
ASSY

3041-27

Wiring 9 – Engine control board, paper size switch board, feed solenoid, no paper sensor, low paper sensor
Service Guide

20

ENGINE CONTROL
BOARD

PAPER FEEDER

FRONT
TRANSPARENCY
SENSOR

REAR
TRANSPARENCY
SENSOR

3041-28

Wiring 10 – Engine control board, paper feeder
210

Phaser 780 Color Printer

PAPER FEEDER

MULTI-PURPOSE TRAY

MULTI-PURPOSE
TRAY EDGE SENSOR

ENGINE CONTROL
BOARD
MULTI-PURPOSE TRAY
EDGE PAPER SENSED (L) 5VDC

MULTI-PURPOSE TRAY OHP SENSED (L) 5VDC

MULTI-PURPOSE TRAY
LONG PAPER SENSED (L) 5VDC

MULTI-PURPOSE
TRAY OHP SENSOR

MULTI-PURPOSE TRAY
LONG N/P SENSOR

MULTI-PURPOSE TRAY
SHORT N/P SENSOR

MULTI-PURPOSE TRAY
SHORT PAPER SENSED (L) 5VDC

MULTI-PURPOSE TRAY
CLUTCH ON (L)

24VDC

MULTI-PURPOSE
TRAY CLUTCH

MULTI-PURPOSE
TRAY PICK UP
SOLENOID

3041-29

Wiring 11 – Engine control board, paper feeder, multi-purpose tray
Service Guide

21

ENGINE CONTROL
BOARD

MEDIA EXIT SWITCH ON (L) 5VDC

3041-30

Wiring 12 – Engine control board, top exit sensor, media exit switch, full stack sensor, fuser fan

212

Phaser 780 Color Printer

ENGINE CONTROL BOARD

IMAGE PROCESSOR
BOARD

IMAGE PROCESSOR FAN

FRONT PANEL

3041-31

Wiring 13 – Engine control board, image processor board, front panel, image processor fan
Service Guide

21

BOARD 1

BOARD 2

BOARD 4

BOARD 3

3041-59

Wiring 14 – Lower Tray Assembly master wiring diagram
214

Phaser 780 Color Printer

3041-60

Wiring 15 – Engine control board and low voltage power supply to Lower Tray Assembly feeder board

Service Guide

21

3041-61

Wiring 16 – Lower Tray Assembly feeder board to feeder chute switch, size switches and feeder motor
216

Phaser 780 Color Printer

3041-62

Wiring 17 – Lower Tray Assembly feeder board to no paper sensors and low paper sensors
Service Guide

21

3041-63

Wiring 18 – Lower Tray Assembly feeder board to feed solenoids and turn chutes
218

Phaser 780 Color Printer

Service Guide

21

220

Phaser 780 Color Printer



---

Source Exif Data:

File Type                       : PDF
File Type Extension             : pdf
MIME Type                       : application/pdf
PDF Version                     : 1.4
Linearized                      : Yes
Create Date                     : 1999:09:02 11:10:52Z
Modify Date                     : 2005:05:30 16:27:58-06:00
Page Count                      : 234
Creation Date                   : 1999:09:02 11:10:52Z
Producer                        : Acrobat Distiller 4.0 for Macintosh
Author                          : Terry E
Mod Date                        : 2005:05:30 16:27:58-06:00
Metadata Date                   : 2005:05:30 16:27:58-06:00
Creator                         : Terry E
Title                           : Book.P780 Train

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