Apple LaserWriter II NT

Apple LaserWriter IINT
	Apple LaserWriter IINT (1988)
Manufacturer	Apple Computer, Inc.
Type	Laser printer
Discontinued	October 1, 1991
Price	US$4,599 (1988 retail)
Interface	LocalTalk, RS-232/RS-422 serial, ADB
Compatible	Macintosh, Apple II, PC (via RS-232)
Dimensions	8.7" H × 20.2" W × 18.7" D
Weight	45 lbs (20.4 kg)
Model	M6000
Power	900W maximum, 90-126V/50-60Hz

The Apple LaserWriter IINT was a midrange laser printer in the LaserWriter II series, released in January 1988 at US$4,599. The IINT positioned between the budget IISC and high-end IINTX models, offering full PostScript Level 1 support and LocalTalk networking. The printer featured a Motorola 68000 processor running at 11.5 MHz with 2 MB of fixed RAM and 1 MB ROM containing 35 built-in fonts. Using the Canon LBP-SX print engine shared across the LaserWriter II line, the IINT delivered 300 dpi resolution at 8 pages per minute. Performance improvements over earlier models came from elimination of memory wait states, providing faster PostScript rasterization. The IINT was discontinued in October 1991, replaced by the LaserWriter IIf.

Technical Specifications

Physical Specifications

Dimensions: 8.7" H × 20.2" W × 18.7" D (221 × 513 × 475 mm)
Weight: 45 lbs (20.4 kg)
Operating temperature: 50°F to 90°F (10°C to 32°C)
Humidity: 20% to 80% non-condensing
Acoustic noise: 48 dBA operating

Performance

Print speed: 8 pages per minute
Resolution: 300 × 300 dpi
First page out: Approximately 30 seconds
Engine life: 300,000 pages rated
Duty cycle: 3,000 pages per month recommended

Power Requirements

Input voltage: 90-126V AC (auto-ranging)
Frequency: 50-60 Hz
Power consumption: 900W maximum
Current draw: 7.5A maximum
Heat output: 3,078 BTU per hour

System Architecture

Processor and Memory

The LaserWriter IINT used an optimized 68000 configuration:

Central Processing Unit:

CPU: Motorola MC68000
Clock speed: 12 MHz crystal (operating at 11.5 MHz)
Data bus: 16-bit
Address bus: 24-bit (16 MB addressable)
Wait states: None (improved from LaserWriter Plus)

Memory Configuration:

ROM: 1 MB mask ROM
RAM: 2 MB total (fixed, soldered to board)
- PostScript workspace and font cache
- Frame buffer for page rasterization

RAM type: Fast DRAM (no wait states)
Memory expansion: None possible
Performance: Faster rasterization than LaserWriter Plus

Controller Board Design

The IINT controller featured improved architecture:

PostScript interpreter: Level 1 implementation
Font management: 35 fonts in ROM
Graphics processing: Vector and bitmap support
Interface logic: PAL-based design
Memory controller: Zero wait-state access

PostScript Implementation

PostScript Specifications:

Version: PostScript Level 1
Licensor: Adobe Systems
Language features: Complete programming language
Graphics: Vector graphics, Bézier curves, transformations
Font handling: Type 1 and Type 3 support
Emulation: Diablo 630 mode available

Performance Improvements:

Eliminated wait states from LaserWriter Plus
Faster font cache management
Improved complex page handling
Reduced processing time for graphics

Print Engine

Canon LBP-SX Engine

The IINT used the improved Canon LBP-SX engine:

Engine Specifications:

Technology: Laser xerography (electrophotographic)
Photosensitive drum: Organic photoconductor (OPC)
Laser type: Semiconductor laser diode
Developer system: Single-component toner
Fusing: Heat roller system
Paper path: Straight-through design

Advantages over LBP-CX:

32% weight reduction
Improved reliability
Quieter operation
Better paper handling
Longer component life

Consumables

Toner cartridge: Apple M6002 or HP 92295A
Yield: Approximately 4,000 pages at 5% coverage
Drum life: Integrated with toner cartridge
Paper tray: 250-sheet capacity letter/legal cassette
Manual feed: Single-sheet bypass for special media

ROM Fonts

The LaserWriter IINT included 35 built-in PostScript Type 1 fonts (same as LaserWriter Plus):

Core Font Families

Times (4 styles):

Times-Roman
Times-Italic
Times-Bold
Times-BoldItalic

Helvetica (8 styles):

Helvetica
Helvetica-Oblique
Helvetica-Bold
Helvetica-BoldOblique
Helvetica-Narrow
Helvetica-Narrow-Oblique
Helvetica-Narrow-Bold
Helvetica-Narrow-BoldOblique

Courier (4 styles):

Courier
Courier-Oblique
Courier-Bold
Courier-BoldOblique

Display Fonts

ITC Avant Garde Gothic (4 styles):

AvantGarde-Book
AvantGarde-BookOblique
AvantGarde-Demi
AvantGarde-DemiOblique

ITC Bookman (4 styles):

Bookman-Light
Bookman-LightItalic
Bookman-Demi
Bookman-DemiItalic

New Century Schoolbook (4 styles):

NewCenturySchlbk-Roman
NewCenturySchlbk-Italic
NewCenturySchlbk-Bold
NewCenturySchlbk-BoldItalic

Palatino (4 styles):

Palatino-Roman
Palatino-Italic
Palatino-Bold
Palatino-BoldItalic

Specialty Fonts

Symbol: Mathematical and Greek characters
ZapfChancery-MediumItalic: Decorative script
ZapfDingbats: Ornaments and symbols

Interfaces

LocalTalk Interface

Primary networking interface for AppleTalk:

LocalTalk Specifications:

Physical layer: RS-422 differential signaling
Data rate: 230.4 kbps
Topology: Bus with daisy-chaining
Maximum nodes: 32 devices theoretical (16 practical)
Protocol: AppleTalk protocol stack
Connector: Mini-DIN-8

LocalTalk Features:

Automatic node addressing
Collision detection and avoidance
Network printer sharing
Compatible with PhoneNET adapters

Serial Interfaces

The IINT provided dual serial connectivity:

RS-232 Interface:

Connector: DB-25 female
Data rate: Up to 19,200 baud
Data format: 8 bits, no parity, 1 stop bit
Flow control: XON/XOFF or hardware (RTS/CTS)
Usage: PC connectivity, terminal access

RS-422 Interface:

Connector: Mini-DIN-8 (shared with LocalTalk)
Data rate: Up to 57,600 baud
Protocol: AppleTalk or serial
Cable length: Up to 1200 feet

Switch-Selectable Modes:

LocalTalk (default)
RS-232 serial
RS-422 serial
Diablo 630 emulation

ADB Port

Like the IISC, the IINT included an unused ADB port:

Connector: 4-pin mini-DIN
Purpose: Reserved for future expansion
Implementation: Non-functional
Removed: Eliminated in IIf and IIg models

Interactive PostScript

Accessible via RS-232 for direct control:

Terminal Access:

Connect terminal to RS-232 port
Settings: 19,200 baud, 8-N-1
Type "executive" to enter interactive mode
Direct PostScript programming possible
Diagnostic information available

Paper Handling

Input Specifications

Standard cassette: 250 sheets
Manual feed: Single sheets
Paper sizes: Letter, Legal, A4, Executive, B5
Paper weight: 16-28 lb bond (60-105 g/m²)
Media types: Plain paper, transparencies, envelopes, labels

Output Specifications

Output tray: 250-sheet capacity face-down
Page order: First page on bottom
Duplex: Manual duplex only
Maximum monthly volume: 3,000 pages

Diagnostic Features

Self-Test Page

The IINT printed a comprehensive test page showing:

Printer model and serial number
ROM version
Installed RAM (2 MB)
Page count
Font samples (all 35 fonts)
PostScript version
Configuration settings

Status Indicators

Front panel LED indicators:

Ready (green): Solid when ready
Data (green): Flashing during data reception
Paper (amber): Paper out or jam
Service (red): Service required

Service Button

DC controller board service button:

Single press: Print test page
Hold during power-on: Continuous test mode

Common Issues and Maintenance

Known Problems

**Common IINT Failures**
Component	Symptoms	Cause	Repair
DC controller	No power, random resets	Capacitor failure	Recap board
Logic board	PostScript errors	RAM failure	Replace RAM (requires desoldering)
Power supply	Voltage instability	Aged capacitors	Replace all electrolytics
Fuser assembly	Poor adhesion, wrinkled pages	Worn roller	Replace fuser unit
Corona wires	Light print, streaking	Contamination	Clean or replace
Paper feed	Multiple feeds, jams	Worn rollers	Clean/replace rollers

Capacitor Issues

The IINT logic board was prone to capacitor failure:

Surface-mount capacitors leak over time
Causes intermittent operation or failure
All capacitors should be replaced preventively
Use 105°C rated replacements

Preventive Maintenance

Service Intervals:

Monthly: Clean corona wires with brush
50,000 pages: General cleaning and inspection
100,000 pages: Replace transfer corona assembly
200,000 pages: Replace fuser assembly
300,000 pages: Major overhaul recommended

Regular Cleaning:

Toner vacuum with appropriate filter
Paper path cleaning with lint-free cloth
Corona wire cleaning with supplied brush
Exterior wipe with damp cloth

Memory Issues

The 2 MB fixed RAM configuration limitations:

Cannot be expanded
Insufficient for very complex documents
May require document simplification
Font downloading limited by available memory

Driver Software

Macintosh Support

System 6.0.3: Minimum requirement
System 7.0-7.5.5: Full support
LaserWriter driver: Version 5.2 or later
Chooser extension: Standard AppleTalk

PC Support

MS-DOS: PostScript drivers available
Windows 3.x: PostScript driver support
OS/2: Native PostScript support
Connection: RS-232 serial cable

Printer Languages

PostScript Level 1: Primary language
Diablo 630: Emulation mode for compatibility
HP LaserJet: Not supported (unlike IINTX)

Service Information

DIP Switch Settings

Internal DIP switches for configuration:

SW1-2: Interface selection (LocalTalk/Serial)
SW3: Diablo 630 emulation
SW4: Reserved
SW5-8: Diagnostic modes

Test Points

DC controller board test points:

+5V DC logic supply
+24V DC motor supply
-12V DC bias supply
High voltage (special probe required)

Voltage Adjustments

Print density: Potentiometer on DC controller
Registration: Mechanical laser alignment
No user-adjustable voltages

Upgrade Options

Controller Board Upgrades

The IINT could be upgraded to:

IIf board: PostScript Level 2, SCSI support
IIg board: PostScript Level 2, Ethernet

Upgrade Process:

Remove IINT controller board
Install replacement board
Update printer drivers
Configure new features

Comparison with Downgrade

The IINT could replace IISC controller for PostScript:

Adds PostScript Level 1
Adds LocalTalk networking
Adds 35 built-in fonts
Increases processor speed

Comparison with LaserWriter II Series

**LaserWriter II Series Specifications**
Feature	IISC	IINT	IINTX	IIf	IIg
Processor	68000 @ 7.45 MHz	68000 @ 11.5 MHz	68020 @ 16.67 MHz	68030 @ 25 MHz	68030 @ 25 MHz
RAM	1 MB fixed	2 MB fixed	2-12 MB	2-32 MB	5-32 MB
PostScript	No	Level 1	Level 1	Level 2	Level 2
Fonts in ROM	0	35	35	35	35
LocalTalk	No	Yes	Yes	Yes	Yes
SCSI	Yes	No	Yes	Yes	Yes
Ethernet	No	No	No	No	Yes
HP PCL	No	No	Yes	Yes	Yes
Price (1988)	$2,999	$4,599	$5,999	-	-
Price (1991)	-	-	-	$3,599	$4,599

Compatibility

System Requirements

Macintosh:

System 6.0.3 or later
LaserWriter driver 5.2 or later
LocalTalk or serial connection

Apple II:

Apple IIgs with AppleTalk card
Apple IIe with Workstation Card

PC:

PostScript-aware application
RS-232 serial port
Appropriate driver software

Network Compatibility

AppleTalk Phase 1 and Phase 2
LocalTalk compatible
PhoneNET compatible
EtherTalk bridge compatible

Service Manual

The LaserWriter II series service manual is available on the Apple Service Source page.

Successor Models

Personal LaserWriter NT

Released July 1990 as lower-cost alternative:

Reduced to 2 MB RAM (non-expandable)
Smaller footprint
Lower price point
Same 68000 processor

LaserWriter IIf

Released October 1991 as direct replacement:

68030 processor at 25 MHz
PostScript Level 2
2-32 MB RAM expandable
SCSI interface added
PhotoGrade and FinePrint options

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