Apple Plw 300.320 Lw 4.600 Ps Service Manual

K

Service Source

PLW 300 & LW 4/600 PS

Personal LaserWriter 300, Personal LaserWriter 320,

LaserWriter 4/600 PS

K

Service Source

Basics

PLW 300 & LW 4/600 PS

Basics Paper Paths - 1

Paper Paths

There are two paper paths in this family of printers. Paper
is fed from the paper cassette or manual-feed slot and
delivered to the face-down tray or the face-up delivery slot.

When the paper delivery selector is in the up position,
paper is delivered face-down. When the selector is in the
down position, paper is delivered face-up. Default delivery
is face-down at the top of the printer.

Basics Paper Paths - 2

Delivery Roller

Toner

Cartridge

Paper Delivery Selector

Face-Down Path

Face-Up Path

Fuser

Transfer Roller

Pickup RollerFuser

Toner

Cartridge

Transfer Roller

Pickup Roller

Basics Sensing System Theory - 3

Sensing System Theory

There are four paper sensors in this family of printers:
PS304, PS303, PS302, and PS301.

PS301

Controller Assembly

PS303

PS304

PS302

Basics Sensing System Theory - 4

Each consists of an actuator and a U-shaped photo
interrupter that is soldered to the controller assembly. If
the actuator is present inside the U, the circuit closes; if
the actuator is absent, the circuit opens. In ready state the
appropriate circuit is closed.

The paper sensors are actuated as an arm or lever swings
against the paper as it moves through the printer.

Sensor Functions

The cassette empty sensor PS304 detects whether there is
paper in the cassette tray. If the printer is set for cassette
feed and the cassette is empty, sensor PS304 determines
that a paper-out condition exists.

Registration paper sensor PS302 detects the presence of
paper in the manual-feed slot and detects misfeeds of both

Basics Sensing System Theory - 5

cassette-fed and manual-fed paper. If the paper does not
reach the top position of this sensor in the required time,
the printer determines that a pick-up delay jam has
occurred.

Winding paper sensor PS303 detects the passage of paper
from the photosensitive drum to the fuser. If the paper does
not pass this sensor in time, the controller board
determines that a jam condition exists.

Paper delivery sensor PS301 detects the passage of paper
through the fuser assembly. If the paper does not pass this
sensor in time, the controller board determines that a jam
condition exists.

Basics Image Formation System - 6

Image Formation System

The nucleus of the printer is the image formation system,
which includes the photosensitive drum, the developing
unit, and the primary charging roller. These components
are contained in the printer's toner cartridge.

Laser Beam

Cleaning Blade

Primary Charging Roller

Static Charge Eliminator

Photosensitive Drum

Cartridge

Blade

Developing Cylinder

Transfer Roller

Basics Image Formation System - 7

The Printing Process

Upon receiving a print signal from the I/O board, the
printer's controller assembly sends power to the main
motor. The main motor, in turn, supplies the power that
rotates the photosensitive drum, developing cylinder,
primary charging roller, and transfer roller.

The primary charging roller applies a uniform negative
charge on the photosensitive drum surface. At the same
time, the laser/scanner assembly emits a laser beam that
scans a latent image onto the surface of the photosensitive
drum.

The latent image on the photosensitive drum becomes visible
when the transfer roller transfers toner onto the developing
cylinder.

Once the image is printed, the cleaner blade removes any

Basics Image Formation System - 8

residual toner on the photosensitive drum surface. Then, as
a final step, the primary charging roller lays a uniform
charge on the photosensitive drum, readying the drum for
the next latent image.

Basics Status LEDs - 9

Status LEDs

The printer has three status LEDs: Ready/In Use, Paper­Out, and Paper-Jam.

While on standby, the printer's Ready/In Use status LED
glows steadily. When a print command is received, the fan
comes on and the Ready/In Use LED flashes.

If the cassette tray is empty and the printer is set for
cassette feed, the Paper-Out LED glows steadily.

If paper is jammed in the printer, the Paper- Jam LED
glows steadily.

Note:

The Personal LaserWriter 320 and LaserWriter 4/
600 PS also use LEDs to indicate errors during diagnostic
mode. Refer to "Engine Diagnostic" in Troubleshooting Tips.

Basics Status LEDs - 10

The four possible LED conditions for this printer are listed
below:

Warmup or
Processing

Normal

Startup Sequence

Ready Paper-Out Paper-Jam

Basics Toner Cartridge - 11

Toner Cartridge

Caution:

drive unit, or floppy disk. Do not place the toner cartridge
in an upright position or turn it upside down.

Before installing a new toner cartridge, hold the cartridge
horizontally as shown and slowly rock it a 45° angle in both
directions to evenly distribute the toner.

Print three or four pages after installing a new cartridge to
remove any toner that might have leaked during installation.

Avoid placing the toner cartridge near a CRT, disk

Drum Exposure

Exposing the toner cartridge to light (even room light for
more than 5 minutes) can damage the cartridge and may
result in blank spots or black stripes on printed pages. To

Basics Toner Cartridge - 12

avoid such exposure:

– Don't leave the rear access door open on the printer

when the toner cartridge is installed.

– Always cover the toner cartridge when you remove it

from the printer.

– Avoid storing opened toner packages in areas that are

exposed to direct sunlight.

Note:

If the cartridge has been irradiated by ordinary light,
you may be able to repair the damage by placing the
cartridge in a dark area, such as a drawer, for several
hours. However, do not expose the cartridge to direct
sunlight.

Basics LaserWriter Safety - 13

LaserWriter Safety

Unplug Printer

LaserWriter printers operate at high voltages. To prevent
serious injury, always switch off the printer and unplug the
AC power cord before servicing the printer.

Laser Beam Safety

Never disconnect the beam-detect cabling or laser shutter
when the printer is switched on. Also be careful not to place
screwdrivers or other shiny objects in the path of the laser
beam. The reflected laser beam, though invisible, can
permanently damage your eyes.

Never remove the cover of a laser/scanner assembly,
whether the printer is powered on or not.

Basics LaserWriter Safety - 14

Fuser Heat

The fuser assembly becomes very hot during printer
operation. Before servicing the fuser assembly, switch off
the printer for at least 5 minutes to allow the fuser
assembly to cool.

Toner Safety

Toner is a nontoxic substance composed of plastic, iron, and
a small amount of pigment. Clean skin and clothing by
removing as much toner as possible with a dry tissue and
then washing with cold water. Hot water causes toner to jell
and permanently fuse into clothing. Toner attacks vinyl
materials, so avoid contact with vinyl.

K

Service Source

Specifications

PLW 300 & LW 4/600 PS

Specifications General - 1

General

Engine

Printing Method

Optical System

Resolution

Imaging Language Supported

Canon P90 engine

Electrophotography using single-component, dry-jumping

development

Semiconductor laser; scanning mirror

300 dots per inch (dpi) (PLW 300 and 320)
600 dpi (LW 4/600 PS)

Quickdraw (PLW 300)
PostScript Level 2 (PLW 320 and LW 4/600 PS)

Specifications General - 2

System Requirements

Macintosh computer with system 6.0.7 or later

Specifications Intro Date - 3

Intro Date

Personal LaserWriter 300

Personal LaserWriter 320

LaserWriter 4/600 PS

June 1993

January 1994

June 1995

Specifications Logic Board - 4

Logic Board

CPU

RAM

ROM

PLW 300: N/A
PLW 320: AMD 29205 processor
LW 4/600 PS: AMD 29200 RISC processor

PLW 300: 512 K
PLW 320: 2 MB (expandable to 8 MB)
LW 4/600 PS: 2 MB (expandable to 6 MB)

PLW 300: N/A
PLW 320: 2.5 MB
LW 4/600 PS: 2.5 MB

Specifications Logic Board - 5

I/O

PLW 300: Serial, externally clocked
PLW 320: LocalTalk
LW 4/600PS: LocalTalk (EtherTalk and TokenTalk connectivity

through LaserWriter Bridge 2.0 software.)

Specifications Performance - 6

Performance

Printing Speed

Duty Cycle

Minimum Life Expectancy

Printable Area

Approximately 4 pages/min. (A4). Actual performance depends

on the images printed and the computer used.

No limit in pages per month

150,000 pages

Maximum printable lines: 8 in. (203 mm)
Minimum top and bottom margins: 0.25 in. (6.35 mm)
Minimum left and right margins: 0.25 in. (6.35 mm)
The Personal LaserWriter 320 requires a total of 4 MB of RAM in

order to print edge to edge on legal paper.

Specifications Paper - 7

Paper

Paper W eights

Cassette T ype

Paper Delivery

Capacity In

Capacity Out

Cassette feed:17-20 lb., single-sheet, photocopy bond
Manual feed:17-28 lb., letterhead and colored stock, standard-

weight

transparency material, envelopes, and labels

Universal (letter, legal, A4, executive)

Face-down/face-up

Cassette: 100 sheets
Manual: Single sheets, envelopes, transparency material, etc.

25 plain sheets (face-down delivery only)

Specifications Paper - 8

Transparency material, labels, and postcard paper are delivered

face-up only and must be removed by hand.

Specifications Fonts - 9

Fonts

Serif Fonts

Sans Serif Fonts

Special-Purpose Fonts

ITC Bookman, Courier, New Century Schoolbook, Palatino, Times,

Chicago, and New York

ITC Avant Garde, Helvetica, Helvetica Narrow, Geneva, and Monaco

Symbol, ITC Zapf Chancery, and ITC Zapf Dingbats

Specifications Electrical - 10

Electrical

Line V oltage

Power Consumption

US/Japan: 100-120 V; 50-60 Hz
Europe/Austrailia: 220-240 V; 50 Hz

Operating: 450 W maximum at 115 V or 220 V
Standby: 10 W or less

Specifications Physical - 11

Physical

Dimensions

Weight

Width: 15.2 in. (38.5 cm)
Depth: 14.9 in. (37.9 cm)
Height: 6.3 in. (16.1 cm)

15.4 lb. (7 kg) without cartridge

Specifications Environmental - 12

Environmental

Temperature

Humidity

Ozone Emission

Operating: 50-90.5° F (10-32.5° C)
Storage: 32-95° F (0-35° C)

Operating: 20-80% relative humidity, noncondensing
Storage: 10-80% relative humidity, noncondensing

Less than 0.05 parts per million maximum, measured in

accordance with ECMA 129 or UL114 standards for ozone

K

Service Source

Troubleshooting

PLW 300 & LW 4/600 PS

Troubleshooting General - 1

General

The first part of this chapter contains quick-reference
troubleshooting information for the Personal LaserWriter
300/320 and LaserWriter 4/600 PS. We encourage you to
review and print out this chapter before troubleshooting a
printer.

At the end of this chapter are troubleshooting flowcharts and
tables. If a table name clearly addresses your problem, you can go
directly to that table. If not, you should go to the flowchart
associated with the version of the printer you are working on.

Troubleshooting 320 Power-On Self Test - 2

320 Power-On Self Test

The Personal LaserWriter 320 goes through a self diagnostic each
time that you plug the printer in. This diagnostic is called the
Power-On Self Test (POST). This test is not the same as the
engine diagnostic (see next topic). Unlike the engine diagnostic
test, POST does not require the placement of any loopback cable.

Note:

POST does not occur on the Personal LaserWriter 300.

Observing how the LEDs extinguish from the time of startup can
help isolate certain failure areas.

• When you plug in a functional printer, all LEDs will illuminate
for a short time.

• The Ready LED extinguishes when no errors are found on the
I/O controller board.

• The Paper-Out LED extinguishes when no errors are found on
the RAM card.

Troubleshooting 320 Power-On Self Test - 3

• Finally the Jam LED extinguishes when no errors are found in
the engine.

Note:

In a functional printer, control will be passed on to the

PostScript interpreter at the end of this sequence.

Troubleshooting Engine Diagnostic - 4

Engine Diagnostic

The Personal LaserWriter 320 and LaserWriter 4/600 PS have
self-diagnostic capability built into the I/O board. When the
printer is in diagnostic mode, the LEDs are displayed in special
diagnostic sequences.

Note:

The Personal LaserWriter 300 does not have self-

diagnostic capability.

To enter the diagnostic mode, switch off the printer, place a serial
loopback cable (P/N 922-1489) into the serial connector on the
I/O board, and switch on the printer.

It may take up to 90 seconds for the diagnostic LEDs to display.

If the diagnostic detects an error, the LEDs will flash repeatedly
through the following sequence until you switch off the printer.

Troubleshooting Engine Diagnostic - 5

1. All LEDs on for 1 second

2. All LEDs off for 1 second

3. <Error configuration> for 1 second

4. All LEDs off for 1 second

See next page for error configurations.

Troubleshooting Engine Diagnostic - 6

LED Error Configurations

Controller Assembly Fuser Assembly Fan Motor

RAM Card Laser Assembly Misc. Engine

Troubleshooting Troubleshooting Tips - 7

Troubleshooting Tips

Isolating Controller Board Problems

If you are unable to print a service test page (see "Service Test
Page"), but the printer does cycle through its normal startup
sequence (the fan comes on and the delivery rollers rotate), you
most likely have a problem with the controller assembly or
pickup solenoid.

Refer to the Take Apart chapter for instructions on how to replace
the pickup solenoid and/or controller assembly.

Light Exposure Problems on Test Prints

When the printer cover is removed, the photosensitive drum
inside the toner cartridge may be exposed to light. This exposure
can affect the quality of your printouts.

Troubleshooting Troubleshooting Tips - 8

Guard against light exposure when printing service test pages and
other printouts by covering the toner cartridge with a piece of
paper.

Interrupting a Print Cycle

Interrupting a print cycle and inspecting the photosensitive drum
can help isolate the cause of print quality problems.

If the image on the surface of the drum exhibits the same problem
as the printed page, the fault is before the drum, probably
somewhere in the imaging system.

If the image on the drum is OK, the fault is after the drum,
probably in the fuser assembly or controller assembly.

To inspect the drum, initiate a printout. Wait approximately 12
seconds after you hear the paper being picked up from the casette
tray and then interrupt the printing process.

Troubleshooting Troubleshooting Tips - 9

You should interrupt the printing process after the image has been
transferred to the paper, but BEFORE the paper exits the fuser.

Remove the toner cartridge and turn it over. Pull back the shield
that covers the photosensitive drum and inspect the drum surface.

Avoiding Paper Jams

The following tips will reduce your chances of a paper jam:

• Don't load already printed pages into the paper cassette—always
use manual feed for printing the second side of two-sided
copies.

• When printing multiple pages via manual feed, wait for the
screen prompt before inserting a new sheet into the printer.

• Make sure that the paper cassette is properly loaded with one of
the recommended paper types.

Troubleshooting Circuit Board Diagrams - 10

Circuit Board Diagrams

On the following pages are diagrams of the circuit boards and
high-voltage contacts listed below:

• Personal LaserWriter 300 I/O Board

• Personal LaserWriter 320I/O Board

• Personal LaserWriter 320 2 MB RAM Expansion Card

• Personal LaserWriter 320 6 MB RAM Expansion Card

• Personal LaserWriter 300/320 Controller Assembly

Troubleshooting Circuit Board Diagrams - 11

LEDs

123

J1
Interface
Connector

Personal LaserWriter 300

I/O Board

J2

Controller

Board

Connector

(opposite side)

Troubleshooting Circuit Board Diagrams - 12

LEDs

123

J1
Interface
Connector

Personal LaserWriter 320

I/O Board

J2

Controller

Board

Connector

(opposite side)

J104

Memory Card

Connector

Troubleshooting Circuit Board Diagrams - 13

Personal LaserWriter 320

I/O Board

The 2 MB RAM Expansion Card mates into J104 on
the Personal LaserWriter 320 I/O board to bring
total RAM to 4 MB. 4 MB of RAM is required to
print edge to edge on legal size paper.

2 MB RAM

Expansion Card

Troubleshooting Circuit Board Diagrams - 14

Personal LaserWriter 320

I/O Board

The 6 MB RAM Expansion Card mates into J104 on
the Personal LaserWriter 320 I/O board to bring
total RAM to 8 MB. 8 MB of RAM is required to
print in PhotoGrade.

6 MB RAM

Expansion Card

Troubleshooting Circuit Board Diagrams - 15

SW301

J601
J202

SW201

J201

Pickup Solenoid

The controller assembly controls the operation of the print engine.
This assembly contains the high-voltage power supply, the four
paper sensors, the printer fuses, the service test page button, and
the pickup solenoid.

J204

Controller Board

Assembly

J206

VR301

J103

Fuses

HVT Assembly

Troubleshooting Wiring Diagram - 16

Wiring Diagram

The wiring diagram for this printer can be found on the next page.
The detail in this document is too small to read easily at 100%
view. You should either zoom into the diagram using the zoom tool
above, or print the diagram on a laser printer with a resolution of
300 dpi (600 dpi preferred).

FAN

+12VGND

FANTAC

FANON

SCANNER

INTERCONNECT

ASSEMBLY

LASER/SCANNER ASSEMBLY

1

2

J804

3

IC801

1 2 3 4 5 6 7 8 9 10 1112 13 14 15 16 17 18

GND

GND

FANON

+12VBS

+12VBS

FANTAC

BD UNIT LASER UNIT

+5V

1234

J802 J803

J801

+5V

/BD

SCNTAC

LPCHG

GND(+5V)

/RO

GND

/BD

SCNCLK

GND(+5V)

123

/SCNON

GND(+5V)

LDPD+5V

+5V

APCSH

/VDOUT

-5V

/BD

J1

/PPRDY

/RDY

/TOP

/SBSY

/STS

I/O BOARD

J2

/PCLK

/CBSY

/PRNT

LED1 LED2 LED3

GND

/CPRDY

/VDO

/CMD

LIGHT PIPE

/CCLK

/RESET

/PRFD

+5V

GND

+5V

FUSER ASSEMBLY

J901

FU901

Fixing
Film

R901

TH901

Paper
Guide

POWER

INLET

J101

H901

Safety Earth

J902

J904

Actuator

Screw

3
2
1

H

1 2 3 4 5 6 7 8 9 10 1112

3
2

J103

1

PS301

Paper
Delivery
Sensor

1
2

J204

3

To Low Voltage
Power Supply Circuit

FU201 100/115V only

FU101

To AC
Driver

J202

13 1415 1617 18

SW301

Test Page

Button

GND

ANGND

12VAS

PAUSD

J301

PISNS

FSRTHR

TOPVR

FMODEO

+5V

10987654321

A1B1A2B2A3B3A4B4A5B5A6B6A7B7A8B8A9

CONTROLLER ASSEMBLY

SW201

Top Cover

Switch

Cover

FMODE1

Interlock
Actuator

VR301

PS302

Registration

Paper Sensor

Arm

Registration

Assembly

PS303

Winding

Paper

Sensor

Actuator

in Feeder

Guide

Assembly

J201

J206

J402 J404 J403 J401

DV GND TR PR

B9

PS304

Cassette

Empty

Sensor

HVT
CONNECTOR
ASSEMBLY

A10

J207

J601

B10

Pickup

Solenoid

SL002

1
2
3
4

PICKUP MOTOR

ASSEMBLY

Actuator

Registration

Solenoid

MAIN

MOTOR

SL001

TONER CARTRIDGE

Troubleshooting Service Test Page - 18

Service Test Page

The service test page is generated by the controller assembly. It
serves to confirm print engine operation.

There are two methods for generating the service test page,
depending on the model of the printer that you are servicing.

Troubleshooting Service Test Page - 19

LaserWriter 4/600 PS

Test Page Lever

To generate a service test page on the LaserWriter 4/600 PS,
raise the edge of the printer and press the plastic service test page
lever underneath the printer. The photos above are taken from
the “Service Test Page LW 4/600” movie that is included on this
CD.

Troubleshooting Service Test Page - 20

Personal LaserWriter 300/320

To generate a service test page on the Personal LaserWriter 300
or 320, perform the steps on the next page.

Toner Cartridge

Cover Interlock Actuator

Paper Delivery Sensor PS301

Test Page Button

Troubleshooting Service Test Page - 21

Remove the printer cover (refer to "Cover" in Take-Apart) and
plug in the printer. Defeat the paper delivery sensor PS301 with
a piece of folded paper. Insert the paper only until it touches the
metal shaft on the fuser. If you insert the paper too far, the
sensor will remain open and the printer will determine that a
paper jam exists.

Folded

Fuser

Paper

Shaft

PS301

Troubleshooting Service Test Page - 22

Cover the toner cartridge with a piece of paper to prevent
exposure of the drum.

Press down on the toner cartridge and the cover interlock actuator
while you press the service test page button with a screwdriver
(or similar dowel-shaped tool).

Note:

When you press down the cover interlock actuator, the fan
should come on and the paper delivery rollers should rotate. If
you don't hear the fan, verify that you have properly defeated the
paper delivery sensor PS301, that you are holding down the cover
interlock actuator all the way, and that the paper cassette is
installed. If you do not press down firmly on the toner cartridge
during the printing process, the test page may be blank.

Troubleshooting Power Failure - 23

Power Failure

AC power failure 1 Verify correct voltage at power outlet.

2 Check power cord connections at printer and outlet.
3 Replace fuse FU101 on controller assembly.
4 Replace controller assembly.

DC power failure 1 Examine cause of tripping of overcurrent detection circuit in

controller assembly.
2 Replace fuse FU201 on controller assembly.
3 Replace controller assembly.

Troubleshooting No Paper Pickup - 24

No Paper Pickup

No pickup (manual
feed)

No pickup (cassette
feed)

1 Check arm registration assembly and replace if broken.
2 Replace pickup motor assembly.
3 Replace controller assembly.

1 Check cassette-empty sensor lever and replace if broken.
2 Replace pickup solenoid on controller assembly.
3 Inspect pickup roller on pickup motor assembly and replace

if damaged.
4 Replace pickup motor assembly.
5 Replace controller assembly.

Troubleshooting Printer Jams - 25

Printer Jams

Paper jam LED lights
when there's no
paper jam

1 Check arm registration assembly and replace if broken.
2 Check paper delivery sensor and replace if broken.
3 Replace controller assembly.

Troubleshooting Motor Failure - 26

Motor Failure

Motor doesn't rotate 1 Verify motor is making good contact with controller

assembly at connector J601.
2 Replace main motor.
3 Replace controller assembly.

Troubleshooting Fan Failure - 27

Fan Failure

Fan doesn't come on 1 Verify fan is making good contact with laser/scanner

assembly at connector J804.
2 Replace fan.
3 Replace controller assembly.

Troubleshooting Fuser Assembly Failure - 28

Fuser Assembly Failure

No power to fuser
assembly

1 Verify fuser assembly is properly seated and making good

contact with controller assembly at connectors J103 and

J204.
2 Replace fuser assembly.

Note:

After replacing the fuser assembly, wait at least 10
minutes before plugging in the printer to allow the capacitor
to discharge.

3 Replace controller assembly.

Troubleshooting Printer Drops After 3 Pages - 29

Printer Drops After 3 Pages

The printer drops
connections to the
Macintosh after
printing three pages.

Replace the fan.

Troubleshooting Environmental Problems - 30

Environmental Problems

Room lights flicker
when printer cycles
to print.

There have been reports of the Personal LaserWriter 300/320
causing sporadic flickering in some incandescent lights when the
printer cycles to print. Replacing the controller assembly has
cured this problem in the cases that have been reported.

PLW 300 Flowchart 1

START

Do

you have a

Macintosh computer

with the LaserWriter 300

driver installed

available

for testing?

Yes

1. Connect the printer to the Macintosh computer that is
using the LaserWriter 300 driver.

2. Open the printer and remove any paper jams.

3. Install the toner cartridge and fill the cassette tray.

4. Switch on the computer and plug in the printer.

No

B

Flowcharts and TablesTroubleshooting

Does the

fan come

on?

Yes

Does the

main motor rotate

during

startup?

Yes

Issue a Print Window or
Print Desktop Command.

Does the

printer print from

a Macintosh?

Yes

No

No

No

Go to Table 1,

No Power to Fan.

Go to Table 2,

Main Motor Failure.

Follow the instructions

given in the error message

that appears on the

Macintosh screen. If the

message indicates a module

malfunction, replace the

module.

Is the print

quality

OK ?

Yes

The printer is fully functional.

No

Go to "Print Quality

Problems."

PLW 300 Flowchart 1 (Continued)

B

1. Remove the printer cover and I/O board.

2. Remove any paper jams.

3. Install the toner cartridge and fill the cassette tray.

4. Plug in the printer.

5. Defeat paper delivery sensor PS301 with a piece of
folded paper (see "Service Test Page.")

6. Cover the laser/scanner assembly with a piece of
paper to prevent exposure to light.

7. Press and hold down on the toner cartridge and the
cover interlock actuator.

Flowcharts and TablesTroubleshooting

Does the
fan come

on?

Yes

Does the

main motor rotate

during

startup?

Yes

Initiate a service test page.
(See "Service Test Page.")

Does the

printer deliver

a service test

page ?

Yes

No

No

No

Go to Table 1,

No Power to Fan.

Go to Table 2,

Main Motor Failure.

Go to Table 3, 4, 5, or 6,

depending on the specific

paper transport problem.

Is the print

quality

OK ?

Yes

The printer is fully functional.

No

Go to "Print Quality

Problems."

Flowcharts and TablesTroubleshooting

PLW 320 and LW 4/600 Flowchart 1

START

Do

you have a

Macintosh computer

with the LaserWriter 8

driver installed

available

for testing?

Yes

1. Connect the printer to the Macintosh computer that is using the LaserWriter 8 driver.

2. Open the printer and remove any paper jams.

3. Install the toner cartridge and fill the cassette tray.

4. Switch on the computer and plug in the printer.

No

B

Does the

fan come

on?

Yes

Does the

main motor rotate

during

startup?

Yes

Issue a Print Window or Print Desktop command.

Does the

printer print from

a Macintosh?

Yes

Is the print

quality

OK ?

Yes

No

No

given in the error message

No

message indicates a module

No

Print Quality Problems.

Go to Table 1,

No Power to Fan.

Go to Table 2,

Main Motor Failure.

Follow the instructions

that appears on the

Macintosh screen. If the
malfunction, replace the

module.

Go to Figure 2,

The printer is fully functional.

Flowcharts and TablesTroubleshooting

PLW 320 and LW 4/600 Flowchart 1 (Continued)

B

1. Remove the printer cover and I/O board.

2. Remove any paper jams.

3. Install the toner cartridge and fill the cassette tray.

4. Plug in the printer.

5. Defeat paper delivery sensor PS301 with a piece of
folded paper (see "Service Test Page").

6. Cover the laser/scanner assembly with a piece of
paper to prevent exposure to light.

7. Press and hold down on the toner cartridge and the
cover interlock actuator.

Does the
fan come

on?

Yes

Does the

main motor rotate

during

startup?

Yes

Initiate a service test page.
(See "Service Test Page.")

Does the
printer deliver
a service test

page?

Yes

No

No

No

Go to Table 1,

No Power to Fan.

Go to Table 2,

Main Motor Failure.

Go to Table 3, 4, 5, or 6,

depending on the specific

paper transport problem.

Is the print

quality

OK?

Yes

The printer is fully functional.

No

Go to Figure 2,

Print Quality Problems.

Flowcharts and TablesTroubleshooting

T roubleshooting T ables

Important

As you proceed through the steps in a table, remember to retry the printer each
time you change its physical state—for example, when you replace a module. If
the problem remains, reinstall the original module before proceeding to the
next step in the table. Refer as necessary to the wiring diagram that follows the
tables.

Table 1. No Power to Fan

Step Check Result Action

1 Make sure the toner

cartridge is installed and
then unplug the printer.
Because of the possibility
of a capacitor error, wait 4
minutes and then plug in
the printer. Does the
problem persist?

2 Is the printer cover

securely seated and the
rear door assembly
installed and securely
closed? Or, if the cover is
removed, do you ha ve the
cover interlock actuator
depressed and the paper
delivery sensor defeated?

No Problem solved.

No Reseat the printer cover and/or install

and close the rear door assembly. Or,
depress the cover interlock actuator
and defeat the paper delivery sensor.

3 Is there correct voltage at

the outlet?

4 Is the power cord securely

connected at the outlet
and at the printer end?

5 Is the fan cable securely

connected to the laser/
scanner assembly?

No Plug in the printer at an outlet that is

supplying the correct voltage.

No Secure the power cord.

No Secure the fan cable.

4

Table 1. No Power to Fan (Continued)

Step Check Result Action

Flowcharts and TablesTroubleshooting

6 Is the fan cable pinched

under the top tab that
secures the fan to the
chassis?

7 Does the voltage

between connector
J804-3 (FANON) and
J804-1 (+12VGND) on the
laser/scanner assembly
change from 0 V to about
12 VDC when you plug in
the printer?

8 Is fuse FU101 on the con-

troller assembly blown?

Yes Make sure the fan cable runs under

the side of the tab.

Yes Replace the fan.

Yes

No

Replace the fuse.

Replace the controller assembly.

Table 2. Main Motor Failure

Step Check Result Action

1 Is the motor properly

seated and making good
contact with the controller
assembly?

No

Yes

Reseat the motor so that it makes
good contact with the controller
assembly.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the motor.

• Replace the controller
assembly.

Table 3. No Paper Pickup from Cassette Tray

Step Check Result Action

1 Have you set the printer

for cassette-feed in the
Print dialog box?

No Select the Cassette option in the Print

dialog box.

Ω

Flowcharts and TablesTroubleshooting

Table 3. No Paper Pickup from Cassette Tray (Continued)

Step Check Result Action

2 Was the toner cartridge

installed before you
plugged in the printer?

3 Try printing with known-

good paper. Does the
problem persist?

4 Remove excess paper

from the cassette tray.
Does the problem persist?

5 Is the paper pickup roller

worn or deformed?

6 Replace the pickup

solenoid on the controller
assembly. Does the
problem persist?

7 Is the fuser assembly

properly seated and
making good contact with
the controller assembly?

No With the toner cartridge installed,

unplug the printer and plug it back in
again.

No Problem solved.

No Problem solved.

Yes Replace the paper pickup roller.

No Problem solved.

No Reseat the fuser assembly so that it

makes good contact with the
controller assembly.

8 Remove the fuser

assembly and measure
the resistance between
connectors J204-1 and
J204-2.

Does the resistance
measure approximately
440 k

9 Is there continuity

between connectors
J103-1 and J103-2?

?

No Replace the fuser assembly.

No

Yes

Replace the fuser assembly.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the controller assembly

• Replace the pickup motor.

4

Flowcharts and TablesTroubleshooting

Table 4. No Paper Pickup From Manual-Feed Slot

Step Check Result Action

1 Is the printer set up for

manual feed?

2 Try printing with known-

good paper. Does the
problem persist?

3 Remove excess paper

from the manual-feed slot.
Does the problem persist?

4 Is the arm registration

assembly broken?

No Select the Manual Feed option in the

Print dialog box.

No Problem solved.

No Problem solved.

Yes

No

Replace the arm registration
assembly.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the pickup
motor.

• Replace the controller
assembly.

• Replace the fuser
assembly.

Table 5. Paper Jams in Pickup/Transfer Area

Step Check Result Action

1 Try printing with known-

good paper. Does the
problem persist?

2 Was the toner cartridge

installed before you
plugged in the printer?

3 Is the paper wrinkled or

damaged?

No Problem solved.

No With the toner cartridge installed,

unplug the printer and plug it back in
again.

Yes Check the inside of the printer for

physical obstructions and make sure
that all paper feed assemblies are
installed correctly.

Flowcharts and TablesTroubleshooting

Table 5. Paper Jams in Pickup/Transfer Area (Continued)

Step Check Result Action

4 Inspect the arm

registration assembly. Is it
jammed or broken?

5 Inspect the winding paper

sensor on the feeder
guide assembly. Is it
jammed or broken?

6 Does the paper jam when

you print a service test
page?

Yes Replace the arm registration

assembly.

Yes Replace the feeder guide assembly.

Yes

No

Replace the fuser assembly.

Replace the pickup motor. If the
problem persists, replace the
controller assembly.

Table 6. Paper Jams in Fuser/Delivery Area

Step Check Result Action

1 Try printing with known-

good paper. Does the
problem persist?

No Problem solved.

2 Is the paper wrinkled or

damaged?

3 Inspect the winding paper

sensor on the feeder
guide assembly. Is it
jammed or broken?

4 Inspect the delivery roller

assembly and passive
delivery rollers. Are they
installed correctly and in
good working order?

Yes Check the inside of the printer for

physical obstructions.

Yes Replace the feeder guide assembly.

No Replace or reseat the delivery roller

assembly and/or passive delivery
rollers.

4

Flowcharts and TablesTroubleshooting

Table 6. Paper Jams in Fuser/Delivery Area (Continued)

Step Check Result Action

5 Remove the rear door

assembly and inspect the
operation of the paper
delivery selector. Does
the assembly move
freely?

6 Test the paper delivery

sensor in the fuser
assembly. Does it appear
to be jammed or broken?

No Replace the rear door assembly.

Yes

No

Replace the fuser assembly.

Replace the controller assembly. If
the problem persists, replace the fuser
assembly .

Flowcharts and TablesTroubleshooting

Print Quality Problems

The following graphic shows examples of image quality defects. Refer to the
appropriate troubleshooting table to correct the quality of the image.

All-Blank Page

See Table 7

Black Vertical

Line(s)

See Table 11

Horizontal

Banding

See Table 15

All-Black Page

See Tablle 8

White Vertical

Line(s)

See Table 12

Black Horizontal

Lines

See Table 16

Light/Faded Image

See Table 9

Irregular

Black Line

See Table 13

Bad Registration

See Table 17

Dark Image

See Table 10

Stairstepping

See Table 14

Skewed Print

See Table 18

Bad Fusing

See Table 19

Legal Size

Print Area

See Table 23

Toner on Back

See Table 20

Blank Spots

See Table 21

No PhotoGrade

Resolution

See Table 22

Flowcharts and TablesTroubleshooting

Table 7. All-Blank Page

Step Check Result Action

1 Has the sealing tape been

removed from the toner
cartridge, and is the
cartridge free from any
other obstructions?

2 If the printer cover is

removed, make sure you
are pressing down on the
toner cartridge during the
printing process so that
the toner cartridge is
making solid contact with
the HVT connector. Does
the problem persist?

3 Are the metal contact

points on the toner
cartridge or HVT
connector assembly dirty?

No Remove the sealing tape or other

obstructions from the toner cartridge.

No Problem solved.

Yes

No

Clean the contact points with a soft,
dry cloth.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the controller
assembly.

• Replace the
laser/scanner assembly.

Table 8. All-Black Page

Step Check Result Action

1 Replace the controller

assembly with a known­good controller
assembly. Does the
problem persist?

No

Yes

Problem solved.

Replace the laser/scanner assembly.

Flowcharts and TablesTroubleshooting

Table 9. Uniformly Light/Faded Image Over Entire Page

Step Check Result Action

1 Remove the toner

cartridge and rock it back
and forth to distribute the
toner evenly. Does the
problem persist?

2 Adjust the print density,

using the Options button
in the Print dialog box,
and print about a dozen
test pages with known­good paper. Does the
problem persist?

3 Replace the toner

cartridge with a
known-good cartridge.
Does the problem persist?

4 Are the metal contact

points on the toner
cartridge or HVT
connector assembly dirty?

No Problem solved.

No Problem solved.

No Problem solved.

Yes

No

Clean the contact points with a soft,
dry cloth.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the transfer
roller assembly.

• Replace the HVT
connector assembly.

• Replace the controller
assembly.

• Replace the
laser/scanner assembly.

4

Flowcharts and TablesTroubleshooting

Table 10. Uniformly Dark Image Over Entire Page

Step Check Result Action

1 Adjust the print density,

using the Options button
in the Print dialog box,
and print about a dozen
test pages with known­good paper. Does the
problem persist?

2 Are the metal contact

points on the toner
cartridge or HVT
connector assembly dirty?

No Problem solved.

Yes

No

Clean the contact points with a soft,
dry cloth.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the controller
assembly.

• Replace the
laser/scanner assembly.

Table 11. Black Vertical Lines, Sharp and Well-Defined

Step Check Result Action

1 Try printing with a known-

good toner cartridge.
Does the problem persist?

2 Does the problem occur

only when you print from
the Macintosh, not when
you print a service test
page?

No Problem solved.

Yes

No

Replace I/O board.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the fuser
assembly.

• Replace the
laser/scanner assembly.

Flowcharts and TablesTroubleshooting

Table 12. White Vertical Lines, Sharp and Well-Defined

Step Check Result Action

1 Is there any type of

physical obstruction near
the laser opening that
could be casting a
shadow on the
photosensitive drum?

2 Does the problem occur

only when you print from
the Macintosh, not when
you print a service test
page?

Yes Remove the obstruction.

Yes

No

Replace the I/O board.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the pickup
motor.

• Replace the
laser/scanner assembly.

• Replace the mirror
assembly.

Table 13. Irregular Black Lines

Step Check Result Action

1 Replace the toner

cartridge. Does the
problem persist?

No Problem solved.

4

Flowcharts and TablesTroubleshooting

Table 14. Stairstepping/Vertical Lines Jagged or Shaky

Step Check Result Action

1 Is the laser/scanner

assembly properly seated
and making good contact
with the scanner
interconnect assembly?

2 Is the scanner

interconnect assembly
properly seated and
making good contact with
the controller assembly?

3 Does the problem appear

when you print a service
test page?

No Reseat the laser/scanner assembly.

No Reseat the scanner interconnect

assembly.

No

Yes

Replace the I/O board.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the
laser/scanner assembly.

• Replace the controller
assembly.

Table 15. Horizontal Banding, Evenly Spaced Smudged

Black Lines Over Image

Step Check Result Action

1 Interrupt a print cycle and

inspect the
photosensitive drum.
Does the fault appear on
the drum?

Yes

No

Replace the toner cartridge.

Replace the fuser assembly.

Flowcharts and TablesTroubleshooting

Table 16. Black Horizontal Lines, Sharp and Well-Defined

Step Check Result Action

1 Does the problem appear

on normal prints, but
definitely not on a service
test page?

Yes

No

Replace the I/O board.

Replace the fuser assembly.
Replace the laser/scanner assembly.

Table 17. Bad Registration

Step Check Result Action

1 Try printing with known-

good paper. Does the
problem persist?

2 Remove the e xcess paper

from the cassette tray or
manual-feed slot. Does
the problem persist?

3 Perform the registration

adjustment (see
“Registration
Adjustment”). Does the
problem persist?

No Problem solved.

No Problem solved.

No

Yes

Problem solved.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Clean or replace the pickup roller as
needed.

• Replace the pickup motor.

• Replace the arm registration
assembly if broken.

• Replace the controller assembly.

4

Flowcharts and TablesTroubleshooting

Table 18. Skewed Print

Step Check Result Action

1 Adjust the mirror

assembly (see “Mirror
Adjustment”). Does the
problem persist?

No Problem solved.

Table 19. Bad Fusing

Step Check Result Action

1 Try printing with known-

good paper. Does the
problem persist?

2 Remove the e xcess paper

from the cassette tray or
manual-feed slot. Does
the problem persist?

3 Perform the registration

adjustment (see
“Registration
Adjustment”). Does the
problem persist?

No Problem solved.

No Problem solved.

No

Yes

Problem solved.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Clean the transfer roller.

• Replace the transfer roller.

• Replace the fuser assembly.

Flowcharts and TablesTroubleshooting

Table 20. Toner on Back of Page

Step Check Result Action

1 Clean the transfer roller

using a dry, lint-free cloth
only. If the roller cannot
be cleaned, replace it.
Does the problem persist?

2 Clean the transfer guide

assembly. Does the
problem persist?

3 Clean the feeder guide

assembly. Does the
problem persist?

No Problem solved.

No Problem solved.

No

Yes

Problem solved.

Replace the fuser assembly.

Table 21. Blank Spots, Random Pattern or Location

Step Check Result Action

1 Try printing with dry,

known-good paper. Does
the problem persist?

No Problem solved.

2 Clean the transfer roller

using a dry, lint-free cloth
only. Does the problem
persist?

No

Yes

Problem solved.

Perform the first module exchange
listed below. If the problem persists,
reinstall the original module and
perform the next exchange:

• Replace the fuser
assembly.

• Replace the transfer
roller.

4

Flowcharts and TablesTroubleshooting

Table 22. No PhotoGrade on Personal LaserWriter 320

Step Check Result Action

1 Have you installed the

6 MB RAM expansion
card?

No Install the 6 MB RAM expansion card

on the I/O board. This will bring the
total RAM to 8 MB. Eight MB of RAM
is required to print in Offgrade.

Table 23. Personal LaserWriter 320 Legal Size Print Area Not

Edge-to-Edge

Step Check Result Action

1 Have you installed the

2 MB RAM expansion
card?

No Install the 2 MB RAM expansion card

on the I/O board. This will bring the
total RAM to 4 MB. Four MB of RAM
is required to print edge-to-edge on
legal size paper.

K

Service Source

T ak e Apart

PLW 300 & LW 4/600 PS

Take Apart Connector Covers - 1

Connector Covers

Interface

Connector

Cover

Power
Connector
Cover

No preliminary steps are
required before you begin
this procedure.

Take Apart Connector Covers - 2

1 Open the connector

covers.

2 Release the tabs at the

top and bottom of each
connector cover, and

Connector

Cover

remove the connector
covers from the main
cover.

Connector

Cover

Take Apart Rear Door Assembly - 3

Rear Door

Rear Door Assembly

Assembly

No preliminary steps are
required before you begin
this procedure.

Take Apart Rear Door Assembly - 4

1 Open the rear door

assembly.

2 Push the assembly to

the right to free the left
hinge and to the left to
free the right hinge.

3 Lift the rear door

assembly out of the
printer.

Rear Door
Assembly

Take Apart Cover - 5

Cover

No preliminary steps are
required before you begin
this procedure.

Cover

Take Apart Cover - 6

1 Open the rear door

assembly and side
connector doors.

Connector
Cover

Connector

Cover

Rear Door
Assembly

Take Apart Cover - 7

2 Push the button on the

right side of the printer
and open the top door of
the cover.

3 Remove the four screws

that secure the cover to
the chassis.

Top Door

Button

Take Apart Cover - 8

4 Grip the two back

corners of the cover and
pull out to release the
back tabs.

5 Grip the two front

corners of the cover and
pull out to release the
front tabs.

6 Lift the cover and

remove it from the
printer.

Take Apart Light Pipe - 9

Light Pipe

Before you begin, remove

Light Pipe

the cover.

Take Apart Light Pipe - 10

1 Turn the cover upside

down.

2 Using a flat-blade

screwdriver, pry up the
small lockwashers that
secure the light pipe to
the cover.

3 Lift the light pipe and

remove it from the
cover.

Take Apart Top Door Assembly - 11

Top Door

Top Door

Assembly

Assembly

Before you begin, remove
the cover.

Take Apart Top Door Assembly - 12

1 Turn the cover upside

down.

2 Using needlenose pliers,

lift up the end of each
spring and release the
spring.

3 Grip the metal bar that

holds each spring. Slide
the bar toward the
middle of the cover until
the bar clears the plastic
hinges.

4 Pull down on the top door

assembly to free the
hinges and remove the
top door assembly from
the cover.

Take Apart Button Lock Assembly - 13

Button Lock Assembly

Button

Lock

Assembly

Before you begin, remove
the cover.

Take Apart Button Lock Assembly - 14

1 Turn the cover upside

down.

2 Using a flat-blade

screwdriver, release the
tabs on either side of the
button lock assembly.

3 Push out the button

assembly and remove it

Button Lock
Assembly

from the cover.

Take Apart Fuser Assembly - 15

Fuser Assembly

Fuser Assembly

Before you begin, remove
the cover.

Take Apart Fuser Assembly - 16

1 Remove the three screws

that secure the fuser
assembly to the chassis.

2 Grip the metal edges of

the fuser assembly and
pull the assembly out of
the printer.

Take Apart Fixing Film Assembly - 17

Fixing Film Assembly

Before you begin, remove
the following:

• Cover

• Fuser assembly

Take Apart Fixing Film Assembly - 18

1 Using needlenose pliers,

release the springs on
the left and right sides of
the fuser (left side

Cable

Clamp

shown).

2 Open the cable clamp on

the left side of the fuser.

Spring

Take Apart Fixing Film Assembly - 19

3 Disconnect the two

connectors on the left
side of the fuser.

Connectors