RetroTechCollection

Macintosh LC 580

The Macintosh LC 580 was introduced on April 3, 1995, as the final 68040-based all-in-one Mac in the LC 500 series. While externally identical to the Macintosh LC 575, the LC 580 featured a redesigned logic board based on the Macintosh LC 630 architecture, introducing IDE hard drive support and video input capabilities to reduce costs. Sold exclusively to educational institutions at $1,300, the LC 580 was positioned $400 below the LC 575's launch price while maintaining the same 33 MHz 68LC040 processor.

Macintosh LC 580
Macintosh LC 580
Specifications
ManufacturerApple Computer, Inc.
TypeAll-in-one personal computer
ReleasedApril 3, 1995
DiscontinuedMarch 2, 1996
Intro priceUS$1,300 (education)
CPUMotorola 68LC040 @ 33 MHz
Memory8 MB RAM (4 MB on-board + 4 MB SIMM) expandable to 52 MB
Storage500 MB IDE hard drive, 2X or 4X CD-ROM drive
DisplayBuilt-in 14" shadow mask CRT (640×480 pixels)
SoundStereo speakers, built-in microphone
Dimensions17.9" H × 13.5" W × 16.5" D (454 × 343 × 419 mm)
Weight40.5 lbs (18.4 kg)
OS / FirmwareSystem 7.1.1 with Enabler 065 – Mac OS 8.1
PredecessorMacintosh LC 575
SuccessorPower Macintosh 5200 LC
Codenamen/a
Model no.M2575

Development & Market Position

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The LC 580 represented Apple's cost-reduction strategy for the education market. By adapting the LC 630's logic board for the all-in-one form factor, Apple achieved several manufacturing economies:

  • IDE storage replaced expensive SCSI drives, following industry trends
  • Shared system RAM for video eliminated separate VRAM modules
  • Video input slot enabled TV tuner and capture card options
  • Dual SIMM slots allowed flexible memory configurations

The switch from Sony Trinitron to shadow mask CRT technology further reduced costs while maintaining acceptable display quality for educational environments. Released alongside the Macintosh LC 630 DOS Compatible, the LC 580 marked the end of 68000-series desktop Mac development.

Model Variants

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Education Market (LC 580)

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  • LC 580 Standard – 8 MB RAM, 500 MB IDE hard drive, 2X CD-ROM
  • LC 580 Enhanced – 8 MB RAM, 500 MB IDE hard drive, 4X CD-ROM

Consumer Market (Performa)

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The Performa variants were sold only outside the United States:

  • Performa 580CD – 5 MB RAM, 250 MB hard drive (Canada, Asia, Australia)
  • Performa 588CD – 8 MB RAM, 500 MB hard drive with KanjiTalk 7.5 (Japan)

Unlike the widespread Performa 575-578 series, Performa 580 models had limited international distribution and were not offered in the U.S. consumer market.

General Maintenance

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Cleaning procedures, capacitor inspection, CRT adjustment, and preventive care are documented in Macintosh LC 580 General Maintenance.

PCB Architecture & Service Documentation

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The LC 580 uses a modified LC 630 logic board (part number 820-0524) adapted for the all-in-one chassis:

Logic Board

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The LC 580 logic board differs significantly from the LC 575:

  • Based on LC 630/Quadra 630 architecture rather than LC 475/Quadra 605
  • IDE controller replaces SCSI for internal hard drive
  • Dual SIMM slots with asymmetric capacity limits
  • Integrated VRAM using 1 MB of soldered system RAM
  • Video input slot for TV/capture cards

Analog Board

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The analog board provides:

  • Power regulation for +5V, +12V, -12V rails
  • CRT drive circuits for 14" shadow mask display
  • Audio amplification for stereo speakers
  • Modified deflection circuits for non-Trinitron CRT

Apple Service Manual

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Service documentation is available on the Apple Service Source page.

Capacitor Replacement Guide

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Surface-mount electrolytic capacitors require periodic replacement. The LC 580 uses the same capacitor layout as the LC 630. Specifications and procedures are documented on the Macintosh LC 580 Capacitor Replacement Guide page.

Troubleshooting

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IDE drive issues, memory recognition problems, display artifacts, and audio faults are covered in the Macintosh LC 580 Troubleshooting guide.

Technical Details

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System Architecture

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Sub-system Specification (Macintosh LC 580, April 1995)
CPU Motorola 68LC040 @ 33 MHz • No FPU (upgradeable to full 68040)
Bus width 32-bit data • 32-bit address (4 GB addressable space)
ROM 1 MB ROM • System 7.1+ support • IDE driver support
RAM 4 MB on-board (1 MB used for VRAM) • expandable to 52 MB via dual SIMMs
Video 1 MB shared system RAM • 640 × 480 at 16-bit color maximum
Sound Stereo 16-bit sound • 44.1 kHz sampling • Built-in stereo speakers
Storage 500 MB IDE hard drive • 2X or 4X CD-ROM (SCSI) • 1.44 MB floppy
I/O Ports ADB × 2 • Mini-DIN-8 serial × 2 • DB-25 SCSI • Audio in/out
Expansion LC PDS • Comm Slot • Video input slot (LC 630-compatible)

Memory Configuration

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The LC 580 features an unusual asymmetric dual-SIMM configuration inherited from the LC 630:

RAM Expansion Options
Configuration On-board SIMM Slot 1 SIMM Slot 2 Total RAM Notes
Minimum 4 MB Empty Empty 4 MB 1 MB used for video
Standard 4 MB 4 MB Empty 8 MB Factory configuration
4 MB 8 MB Empty 12 MB
4 MB 16 MB Empty 20 MB
4 MB 32 MB Empty 36 MB Slot 1 maximum
4 MB 32 MB 1 MB 37 MB Slot 2 limited options
4 MB 32 MB 4 MB 40 MB
Maximum 4 MB 32 MB 16 MB 52 MB Unusual limit

SIMM Slot Limitations:

  • Slot 1: Accepts 1, 2, 4, 8, 16, or 32 MB SIMMs (full range)
  • Slot 2: Accepts only 1, 4, or 16 MB SIMMs (restricted)
  • 72-pin, 80ns or faster required
  • Single-banked 64 MB SIMMs work in Slot 1 only
  • Double-banked 64 MB SIMMs not supported

Display Specifications

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The LC 580 replaced the LC 575's Sony Trinitron with a cheaper shadow mask CRT:

Shadow Mask vs Trinitron Comparison
Feature LC 580 (Shadow Mask) LC 575 (Trinitron)
Technology Shadow mask with triangular phosphor triads Aperture grille with vertical phosphor stripes
Brightness Lower (mask blocks more electrons) Higher (grille more efficient)
Color saturation Good Superior
Sharpness Good text clarity Slightly softer text
Artifacts None Two horizontal stabilization wires visible
Cost Lower Higher
Dot pitch 0.28mm 0.26mm aperture grille

Display Capabilities:

  • 640 × 480 at 256 colors (8-bit)
  • 640 × 480 at thousands of colors (16-bit)
  • 560 × 384 at 16 colors (Apple IIe Card mode)
  • 60 Hz refresh rate
  • 14" diagonal viewable area

The plastic bezel was slightly modified to accommodate the different CRT tube depth.

IDE Storage Subsystem

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The LC 580 was the first LC 500 series Mac with IDE storage:

IDE Controller Specifications:

  • Interface: Single-device IDE (no slave support)
  • PIO Mode: Mode 3 maximum (11.1 MB/s theoretical)
  • Common drives: Western Digital Caviar, Quantum ProDrive
  • Capacities: 250 MB or 500 MB standard

IDE Compatibility Issues:

  • Early versions of Apple HD SC Setup (System 7.5.1 and earlier) cannot recognize modern IDE drives
  • Requires Drive Setup 1.0.3 or later (System 7.5.2+) for proper formatting
  • Some third-party drives require manufacturer-specific utilities

Video Input Capabilities

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The LC 580 introduced a video input slot compatible with LC 630 expansion cards:

Compatible Video Cards:

  • Apple Video System Card – Basic video capture
  • Apple TV/Video System Card – TV tuner with remote control
  • Third-party capture cards designed for LC 630

Video Input Specifications:

  • Composite video input (NTSC/PAL)
  • S-Video input on some cards
  • Real-time video overlay capability
  • QuickTime capture support

This feature allowed the LC 580 to function as both computer and television, particularly appealing for classroom multimedia applications.

Expansion Slots

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LC PDS (Processor Direct Slot)

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  • 114-pin connector (LC III/520 enhanced standard)
  • Backward compatible with 96-pin LC cards
  • Direct 68040 bus access at 33 MHz
  • Common cards: Apple IIe Card, Ethernet adapters, accelerators

Communication Slot

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  • Original Comm Slot standard (not Comm Slot II)
  • Based on LC PDS architecture
  • Modem installation disables external modem port
  • Compatible cards: 14.4/28.8 kbps modems, 10BASE-T Ethernet

Video Input Slot

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  • LC 630-specific connector
  • Provides direct video path to display circuitry
  • Power and control signals for TV tuner cards
  • Not present in LC 575 or earlier models

Custom Chips & Controllers

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Chip Function Details
68LC040 Main CPU 33 MHz, no FPU (field-upgradeable to 68040)
SWIM II Floppy controller Supports 400K, 800K, 1.44 MB disks
NCR 53C96 SCSI controller For CD-ROM and external devices only
IDE controller Hard drive interface Integrated into chipset, PIO Mode 3
CUDA ADB/Power management Handles ADB, power control, PRAM
AWACS Audio controller 16-bit stereo sound generation

PowerPC Upgrade Path

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Apple offered the Macintosh Processor Upgrade Card for the LC 580:

  • PowerPC 601 at 50 MHz (Apple) or 100 MHz (third-party)
  • Installs in LC PDS slot
  • Enables Mac OS 8.5-9.1 support
  • Maintains 68040 emulation for older software

Additionally, the LC 580 logic board can be replaced with boards from:

  • Power Macintosh 5200 LC
  • Power Macintosh 6200 series
  • Performa 5260, 5300, 6300 series
  • Power Macintosh 5400, 6400, 5500, 6500 (requires power supply upgrade)

Overclock Modification

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The LC 580 shares its logic board design with the LC 630, enabling a 40 MHz overclock:

  • Same resistor modification as LC 630 (remove specific resistors)
  • Increases CPU speed from 33 MHz to 40 MHz
  • 21% performance improvement
  • DOS Compatibility Card (if installed) remains unaffected
  • Procedure documented in LC 630 overclocking guides

Known Issues & Solutions

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Common Failures

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  • IDE drive recognition – System 7.5.1 and earlier cannot see modern IDE drives
  • Memory limits confusion – Asymmetric SIMM slots cause upgrade frustration
  • Display quality perception – Shadow mask appears dimmer than Trinitron
  • Capacitor leakage – Surface-mount capacitors damage traces
  • PRAM battery corrosion – 3.6V lithium battery leaks over time

IDE Drive Solutions

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  • Boot from System 7.5.2 or later floppy/CD
  • Use Drive Setup 1.0.3 or higher
  • Third-party formatting utilities (FWB Hard Disk Toolkit)
  • Maximum addressable capacity: 8 GB (IDE controller limitation)

Memory Upgrade Strategies

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  • Install largest SIMM in Slot 1 first (up to 32 MB)
  • Add 1, 4, or 16 MB to Slot 2 for incremental upgrade
  • Avoid double-banked 64 MB SIMMs
  • Test with known-good SIMMs if recognition issues occur

Display Enhancement

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  • Adjust brightness/contrast controls on analog board
  • Degauss CRT if color purity problems appear
  • Clean CRT face and internal dust accumulation
  • Consider that shadow mask technology trades brightness for geometry accuracy

Historical Context

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The LC 580 served as a transitional model between 68K and PowerPC architectures:

  • Final 68040-based all-in-one Mac (alongside LC 630 DOS Compatible)
  • Introduced IDE storage to reduce costs for education market
  • Video input capability anticipated multimedia classroom needs
  • $400 price reduction from LC 575 made it attractive to budget-conscious schools

Production ran for only 11 months before replacement by the PowerPC-based Power Macintosh 5200 LC. The LC 580's cost-cutting measures were controversial among Mac enthusiasts who viewed the shadow mask display and IDE drive as downgrades, though schools appreciated the lower price point.

Design Compromises

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The LC 580's design reflected several engineering trade-offs:

Cost Reductions

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  • Shadow mask CRT saved approximately $50 per unit
  • IDE controller eliminated expensive SCSI chipset for internal drive
  • Shared system RAM for video removed VRAM socket and chips
  • LC 630 board reuse avoided new logic board development

Performance Impact

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  • IDE drive slower than SCSI predecessors (especially with fragmentation)
  • Shared video memory reduced available system RAM
  • Shadow mask perceived as less vibrant than Trinitron
  • No performance improvement over year-old LC 575

User Benefits

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  • Video input capability unique in Mac all-in-one lineup
  • Dual SIMM slots (despite limitations) offered upgrade flexibility
  • Lower price made 68040 performance accessible to more schools
  • LC 630 board compatibility enabled future PowerPC upgrades

Maintenance Resources

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