Tektronix Z780N - Phaser 780 Color Laser Printer User manual

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
PHASER® 780
COLOR LASER PRINTER
Service Reference Guide

Users safety summary
Terms in
CAUTION Conditions that can result in damage to the product.
manual:
WARNING 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
CAUTION A personal injury hazard exists that may not be
product:
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.
Donot 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.
9008-78
DANGER:
Invisible laser radiation
when open and interlock
defeated.
AVOID DIRECT
EXPOSURE TO BEAM.
CAUTION:
Invisible laser radiation
when open and
interlocks defeated.
AVOID DIRECT
EXPOSURE TO BEAM.
VORSICHT:
Unsichtbare Laserstrahlung,
wenn Abdeckung geöffnet
und Sicherheitsverriegelung
überbrückt.
NICH DEM STRAHL
AUSSETZEN.
ATTENTION:
Rayonnement laser invisible
dangereux en cas
d'ouverture et lorsque
la sécurité est neutralisée.
EXPOSITION DANGEREUSE
AU FAISCEAU. Class 3B
PELIGRO:
Cuando se abre y se
invalida el bloqueo, se
producen radiaciones
invisibles de láser.
EVITESE LA
EXPOSICION
DIRECTA A TALES
RAYOS.
´
VARNING:
Osynlig laser-
strálning när denna
del är öppnad och
spärrar är
urkopplade.
STRÅLEN
ÄR FARLIG.
VARNING:
Osynlig laserstrálning
när denna del är
öppnad och spärrar är
urkopplade.
BETRAKTA EJ
STRÅLEN.
VAROI:
Näkymätön
avattaessa ja
suojalukitus
ohitettaessa olet
alttiina lasersäteilylle.
ÄLÄ KATSO
SÄTEESEN.
ADVARSEL:
Usynlig laserstràling
ved abning når
sikkerhedsafbrydere
er ude af funktion.
UNDGÅ UD
ÆTTELSE FOR
STRÅLING.
ADVARSEL:
Usynlig laserstraling
nar deksel åpnes og
sikkerhedslas brytes.
UNNGÅ
EKSPONERING
FOR STRÅLEN.
PJQT4521ZA

Service Guide
vii
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 19
Troubleshooting 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. 53
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

viii Phaser 780 Color Printer
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 77
Recommended tools 77
Cleaning 78
Resetting NVRAM 79

Service Guide
ix
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

x Phaser 780 Color Printer
FRU List 137
Supplies and accessories 176
Test Prints 179
Wiring Diagrams 185

Service Guide
xi
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