Apple LaserWriter Plus

Apple LaserWriter Plus
	Apple LaserWriter Plus (1986)
Manufacturer	Apple Computer, Inc.
Type	Laser printer
Discontinued	February 1, 1988
Price	US$6,798 (1986 retail)
Interface	LocalTalk (RS-422), RS-232 serial
Compatible	Macintosh, Apple II, PC (via RS-232)
Dimensions	11.5" H × 18.5" W × 16.2" D
Weight	77 lbs (35 kg)
Model	M0180
Power	760W maximum, 115V/60Hz

The Apple LaserWriter Plus was the second model in the LaserWriter series, announced on January 16, 1986 at the Apple World Conference in San Francisco and released in March 1986 at US$6,798. The LaserWriter Plus maintained the same Canon LBP-CX print engine and hardware specifications as the original LaserWriter but doubled the ROM capacity from 512 KB to 1 MB, allowing for 35 built-in PostScript fonts instead of 13. The expanded font library made the LaserWriter Plus the definitive PostScript printer, establishing the 35-font set as an industry standard that remained through PostScript Level 2. Both the LaserWriter and LaserWriter Plus were discontinued on February 1, 1988, replaced by the more compact LaserWriter II series.

Technical Specifications

Physical Specifications

Dimensions: 11.5" H × 18.5" W × 16.2" D (292 × 470 × 411 mm)
Weight: 77 lbs (35 kg)
Operating temperature: 50°F to 90°F (10°C to 32°C)
Humidity: 20% to 80% non-condensing
Acoustic noise: 50 dBA operating, 40 dBA standby

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: 115V AC ±10%
Frequency: 60 Hz
Power consumption: 760W maximum
Current draw: 6.3A maximum
Heat output: 2,599.2 BTU per hour

System Architecture

Processor and Memory

The LaserWriter Plus used identical processing hardware to the original LaserWriter:

Central Processing Unit:

CPU: Motorola MC68000
Clock speed: 12 MHz crystal (operating at 11.16 MHz)
Data bus: 16-bit
Address bus: 24-bit (16 MB addressable)
Wait states: 1 wait state on memory access (performance limitation)

Memory Configuration:

ROM: 1 MB mask ROM (doubled from original)
RAM: 1.5 MB total DRAM
- 512 KB workspace RAM for PostScript interpreter
- 1 MB frame buffer for page rasterization

RAM type: 150ns DRAM chips
Memory expansion: None (fixed configuration)

Controller Board Design

The LaserWriter Plus maintained the streamlined PAL-based architecture:

Logic implementation: Monolithic Memories medium-scale integration PALs
Address decoding: PAL-based memory management
Timing control: PAL-generated signals for DRAM refresh and video timing
Bus interface: Direct 68000 bus connection to memory and I/O
ROM addressing: Extended addressing for 1 MB ROM space

PostScript Interpreter

The LaserWriter Plus featured the same PostScript implementation with expanded font resources:

PostScript Implementation:

Version: PostScript Level 1
Licensor: Adobe Systems
Language features: Complete programming language with stack-based execution
Graphics capabilities: Vector graphics, Bézier curves, arbitrary transformations
Font handling: Type 1 outline fonts with hinting
Font cache: Dynamic allocation in RAM

Interpreter Performance:

Rasterization: Real-time interpretation during printing
Complex pages: Could require several minutes for full rasterization
Memory management: Dynamic allocation for fonts and graphics

Print Engine

Canon LBP-CX Engine

The LaserWriter Plus utilized the same Canon LBP-CX laser print engine as the original:

Engine Specifications:

Technology: Laser xerography (electrophotographic)
Photosensitive drum: Organic photoconductor (OPC)
Laser type: Semiconductor laser diode
Developer system: Single-component toner
Fusing: Heat roller at approximately 180°C

Print Process:

Drum charging to -600V
Laser exposure creating latent image
Toner development using magnetic brush
Transfer to paper via corona wire
Thermal fusing of toner to paper
Drum cleaning and discharge

Consumables

Toner cartridge: Apple M0180 or HP 92285A (cross-compatible)
Yield: Approximately 3,000 pages at 5% coverage
Drum life: Integrated with toner cartridge
Paper tray: 250-sheet capacity letter/legal cassette
Manual feed: Single-sheet bypass for envelopes/transparencies

ROM Fonts

The LaserWriter Plus included 35 built-in PostScript Type 1 fonts in its 1 MB ROM, establishing what became the standard PostScript font set:

Original 13 Fonts (from LaserWriter)

Times (4 styles):

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

Helvetica (4 styles):

Helvetica
Helvetica-Oblique
Helvetica-Bold
Helvetica-BoldOblique

Courier (4 styles):

Courier
Courier-Oblique
Courier-Bold
Courier-BoldOblique

Symbol (1 style):

Symbol (mathematical and Greek characters)

Additional 22 Fonts (New in Plus)

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

Helvetica Narrow (4 styles):

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

New Century Schoolbook (4 styles):

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

Palatino (4 styles):

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

ITC Zapf Chancery (1 style):

ZapfChancery-MediumItalic

ITC Zapf Dingbats (1 style):

ZapfDingbats (ornaments and symbols)

These 35 fonts became the de facto standard for PostScript printers and were included in PostScript Level 2 specifications.

Interfaces and Connectivity

LocalTalk Interface

Primary connection method using Apple's LocalTalk networking:

LocalTalk Specifications:

Physical layer: RS-422 differential signaling
Data rate: 230.4 kbps
Topology: Bus with daisy-chaining
Maximum nodes: 32 devices (practical limit ~16)
Maximum distance: 1000 feet (305 m) total bus length
Connector: DB-9 female on printer
Protocol: AppleTalk protocol stack

LocalTalk Connector Pinout (DB-9):

Pin	Signal	Direction
1	Frame Ground	-
2	RxD+	Input
3	RxD-	Input
4	TxD+	Output
5	TxD-	Output
6-9	Not connected	-

RS-232 Serial Interface

Secondary interface for PC compatibility:

RS-232 Specifications:

Connector: DB-25 female
Data rate: Up to 19,200 baud (9,600 baud typical)
Data format: 8 bits, no parity, 1 stop bit
Flow control: XON/XOFF or hardware (RTS/CTS)
Protocol: PostScript commands or Diablo 630 emulation

Interactive PostScript Mode

Accessible via RS-232 for direct printer control:

Terminal Connection:

Settings: 19,200 baud, 8-N-1
Access command: Type "executive" to enter interactive mode
Capabilities: Direct PostScript programming, diagnostics, font management
Error messages: Displayed on terminal for debugging

LaserWriter to LaserWriter Plus Upgrade

Apple offered an upgrade kit to convert original LaserWriter printers to LaserWriter Plus specifications:

Upgrade Kit Contents

ROM chips: Four 256 KB ROM chips to replace original 128 KB chips
Installation manual: Detailed service instructions
Font diskettes: Screen fonts for Macintosh
Price: US$799 (1986)

Installation Requirements

The upgrade process required:

Opening the printer case
Removing the controller board
Desoldering original ROM chips (if not socketed)
Installing IC sockets (if required)
Installing new ROM chips
Reassembling printer
Testing with font verification page

Upgrade Considerations

Required technical expertise or dealer installation
Some early LaserWriter units had soldered ROMs requiring socket installation
Risk of damage to expensive printer if improperly performed
Warranty implications if user-installed

Paper Handling

Input Specifications

Standard cassette: 250 sheets
Manual feed: Single sheets
Paper sizes: Letter, Legal, A4, Executive
Paper weight: 16-24 lb bond (60-90 g/m²)
Media types: Plain paper, transparencies, envelopes

Output Specifications

Output tray: 250-sheet capacity face-down
Stacking: Offset stacking not supported
Duplex: Manual duplex only

Diagnostic Features

Self-Test Page

The LaserWriter Plus printed an enhanced self-test page showing:

Printer serial number
ROM version (Plus-specific)
Installed RAM
Page count
Complete font samples (all 35 fonts)
PostScript version
Print engine status

Status Lights

Three LED indicators on the front panel:

Ready: Solid green when ready to print
Paper: Amber when paper low or jam
Service: Red for errors requiring service

Font Verification

Special test page showing all 35 built-in fonts with sample text demonstrating each typeface in various sizes.

Common Issues and Maintenance

Preventive Maintenance

Regular Service Intervals:

50,000 pages: Clean corona wires, check paper path
100,000 pages: Replace transfer corona assembly
200,000 pages: Replace fuser assembly
300,000 pages: Major overhaul recommended

Cleaning Procedures:

Toner vacuum: Use only toner-rated vacuum
Corona wires: Clean with provided brush monthly
Paper path: Wipe with lint-free cloth
Exterior: Damp cloth with mild detergent

Common Failures

**Typical Failure Modes**
Component	Symptoms	MTBF	Repair
Fuser assembly	Poor toner adhesion, wrinkled pages	200K pages	Replace unit
Corona wires	Light print, streaking	100K pages	Clean or replace
Pickup rollers	Paper feed failures	100K pages	Clean or replace
DC controller	No power, intermittent operation	5-7 years	Board-level repair
Scanner motor	Horizontal lines, distorted print	300K pages	Replace motor assembly
ROM chips	Missing fonts, PostScript errors	10+ years	Replace ROM chips

Power Supply Issues

The LaserWriter Plus used the same power supply as the original, prone to capacitor failures:

Common Symptoms:

Intermittent power
Failure to maintain ready state
Random resets during printing
Voltage regulation problems

Capacitor Replacement:

Replace all electrolytic capacitors as preventive maintenance
Use 105°C rated capacitors for longevity
Typical service life: 5-7 years

PostScript Programming

Font Management

The LaserWriter Plus's expanded font set allowed more sophisticated typography:

Font Selection Example: ``` %!PS /Palatino-Roman findfont 12 scalefont setfont 72 720 moveto (LaserWriter Plus with 35 fonts) show showpage ```

Memory Considerations

VM (Virtual Memory): 512 KB available (same as original)
Font cache: Shared among 35 fonts (vs. 13 in original)
Performance impact: Slightly slower font switching with larger ROM
Downloaded fonts: Less RAM available due to larger font cache requirements

Font Substitution

The LaserWriter Plus established standard font substitutions:

Times → Times-Roman
Helvetica → Helvetica (already included)
Courier → Courier (already included)
These mappings became industry standards

Service Information

Service Mode Access

Internal DIP switches provided service functions:

SW1: Continuous self-test with all fonts
SW2: Suppress startup page
SW3: Diablo 630 emulation mode
SW4: Reserved

Test Points

The DC controller board included test points for:

+5V DC logic supply
+24V DC motor supply
-24V DC bias supply
High voltage (measure with appropriate probe)

Adjustment Procedures

Print density: Potentiometer on DC controller
Registration: Mechanical adjustment of laser unit
Fuser temperature: Thermistor calibration

Compatibility

Operating System Support

System 2.0 or later: Full LaserWriter Plus support with new fonts
System 6.x: Optimal performance
System 7.x: Supported through 7.5.5
Apple II: Via AppleWorks with font selection
MS-DOS: PostScript drivers with full font access
UNIX: lpr with PostScript support

Application Support

Applications with LaserWriter Plus font support:

Aldus PageMaker 1.2 and later (font menu expansion)
MacWrite 4.5 and later
MacDraw 1.9 and later
Microsoft Word 1.05 for Macintosh
Adobe Illustrator 88
Ready,Set,Go! 3.0
QuarkXPress 1.0

Service Manual

The complete Apple LaserWriter Plus service manual is available on the Apple Service Source page.

Comparison with Original LaserWriter

**LaserWriter vs. LaserWriter Plus**
Feature	LaserWriter (1985)	LaserWriter Plus (1986)
ROM size	512 KB	1 MB
Built-in fonts	13	35
Launch price	US$6,995	US$6,798
Weight	77 lbs	77 lbs
Print engine	Canon LBP-CX	Canon LBP-CX
Processor	68000 @ 11.16 MHz	68000 @ 11.16 MHz
RAM	1.5 MB	1.5 MB
Resolution	300 dpi	300 dpi
Speed	8 ppm	8 ppm

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