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| manufacturer = Apple Computer, Inc.
| manufacturer = Apple Computer, Inc.
| type        = Personal Computer
| type        = Personal Computer
| release_date = March 02, 1987
| release date = March 2, 1987
| discontinued = October 15, 1990
| discontinued = October 15, 1990
| price        = US$2,898 – $3,898
| price        = US$2,898 (dual floppy) – $3,898 (with 20MB HD)
| cpu          = Motorola 68000 @ 8 MHz
| cpu          = Motorola 68000 @ 7.8336 MHz
| memory      = 1 MB RAM (expandable to 4 MB)
| memory      = 1 MB RAM (expandable to 4 MB)
| storage      = 800 KB or 1.44 MB floppy drive, optional SCSI hard drive
| storage      = 800 KB or 1.44 MB floppy drive, optional 20-40 MB SCSI hard drive
| display      = 9" monochrome CRT (512×342 pixels)
| display      = 9" monochrome CRT (512×342 pixels)
| sound        = Monaural 8-bit
| sound        = Monaural 8-bit, 22.254 kHz
| dimensions  = 13.6" H × 9.6" W × 10.9" D
| dimensions  = 13.6" H × 9.6" W × 10.9" D (345 × 244 × 277 mm)
| weight      = 17 lbs (7.7 kg)
| weight      = 17 lbs (7.7 kg)
| os          = System 4.0 – System 7.5.5
| os          = System 4.0 – System 7.5.5
| predecessor  = [[Macintosh Plus]]
| predecessor  = [[Macintosh Plus]]
| successor    = [[Macintosh SE/30]]
| successor    = [[Macintosh SE/30]], [[Macintosh Classic]]
| codename    = Sandwich
| codename    = PlusPlus, Aladdin, Chablis, Freeport
| model        = M5010
| model        = M5010 (800K), M5011 (FDHD)
}}== Historical Background ==
}}
The '''Macintosh SE''' was introduced in March 1987 as Apple’s follow-up to the successful [[Macintosh Plus]]. It featured several key advancements, including an internal expansion slot, a fan for improved cooling, and an optional internal SCSI hard drive — making it the first compact Mac to offer that flexibility.


With a Motorola 68000 CPU running at 8 MHz and support for up to 4 MB of RAM, the SE delivered improved performance and reliability. It came in two primary configurations: one with dual 800 KB floppy drives, and another with a single floppy and a 20 MB SCSI hard drive (known as the SE/20). A later revision added support for Apple’s 1.44 MB "SuperDrive" floppy disks.
The '''Macintosh SE''' (System Expansion) was introduced on March 2, 1987, alongside the [[Macintosh II]]. The SE added an internal expansion slot (PDS), cooling fan, support for internal SCSI hard drives, and [[Apple Desktop Bus]] (ADB) for peripherals. Configurations ranged from dual 800 KB floppy drives to combinations with 20 MB or 40 MB internal hard drives.
 
== Model Variants ==
 
The Macintosh SE was produced from 1987 to 1990 in several configurations:
 
=== Original SE Models (1987-1989) ===
* '''Macintosh SE Dual Floppy''' – Two internal 800 KB floppy drives, no hard drive
* '''Macintosh SE 1/20''' – One 800 KB floppy drive, 20 MB internal SCSI hard drive
* '''Macintosh SE 1/40''' – One 800 KB floppy drive, 40 MB internal SCSI hard drive
 
Original SE models used the IWM (Integrated Woz Machine) floppy controller chip and were limited to 800 KB double-sided floppy disks.
 
=== Macintosh SE FDHD (1989-1990) ===
[[File:Apple Mac SE (Little Apple Museum) (8032166773).jpg|thumb|294x294px|Macintosh SE FDHD with "FDHD" marking on front panel]]
In August 1989, Apple introduced the '''Macintosh SE FDHD''' (Floppy Disk High Density), which supported 1.44 MB high-density floppy disks. The FDHD model included:
 
* '''SWIM chip''' (Super Woz Integrated Machine) replacing the IWM controller
* '''Updated ROM''' (minimum System 6.0.3 required) with SWIM driver support
* '''Sony MPF-75W SuperDrive''' mechanism supporting 1.44 MB MFM-encoded disks
* Backward compatibility with 400 KB and 800 KB Macintosh disks
* '''PC Exchange compatibility''' – ability to read/write MS-DOS formatted disks
 
The FDHD upgrade was available as a dealer-installed kit (including ROMs, SWIM chip, and drive) for existing SE owners at US$699. In late 1989, Apple renamed the SE FDHD to '''Macintosh SE SuperDrive''', though the hardware remained identical.


== General Maintenance ==
== General Maintenance ==
For cleaning, inspection, battery replacement, and system longevity practices, refer to [[Macintosh SE General Maintenance]].
Cleaning procedures, PRAM battery management, connector maintenance, and preventive care are documented in [[Macintosh SE General Maintenance]].


== PCB Schematics & Service Manual ==
== PCB Schematics & Service Manual ==
The Macintosh SE consists of two primary circuit boards:
=== Logic Board ===
The SE logic board used two custom VLSI chips that replaced the six PAL chips from earlier models:
* '''BBU''' (Bob Bailey Unit) – VLSI custom chip for memory management
* '''GLU''' (General Logic Unit) – HAL16L8 PAL replacement handling glue logic and bus arbitration


The Macintosh SE includes a '''Logic Board''' and an '''Analog Board''' which work together to drive the compact Mac’s architecture.
=== Analog Board ===
The analog board provides power regulation, CRT drive circuits, and video amplification. Components include the flyback transformer, voltage regulators, and deflection circuits.


=== Apple Service Manual ===
=== Apple Service Manual ===
All Apple Service Manuals can be found on the [[Apple Service Manuals]] page. The SE-specific service manual is here: [[File:Macintosh_SE.pdf|center|thumb|Apple Service Manual – Macintosh SE]]
<pdf width="800" height="500">File:Macintosh_SE.pdf</pdf>
 
Service documentation is available on the [[:Category:Apple Service Source|Apple Service Source]] page.


=== Logic Board & Analog Board Schematics ===
=== Logic Board & Analog Board Schematics ===
{| class="wikitable" style="width:50%; text-align:center;"
{| class="wikitable" style="width:60%; text-align:center;"
|+'''Macintosh SE PCB Schematics'''
|+'''Macintosh SE PCB Schematics'''
|-
|-
! style="background-color:#f2f2f2;"| Logic Board
! style="background-color:#f2f2f2; width:50%;"| Logic Board
! style="background-color:#f2f2f2;"| Analog Board
! style="background-color:#f2f2f2; width:50%;"| Analog Board
|-
|-
| [[File:MacintoshSE_LogicBoard.jpg|thumb|center|250px|Macintosh SE Logic Board]][[File:Macintosh SE Logic Schematic.png|center|thumb|Macintosh SE Logic Board Schematic]]
| [[File:MacintoshSE_LogicBoard.jpg|thumb|center|300px|Macintosh SE Logic Board]][[File:Macintosh SE Logic Schematic.png|center|thumb|300px|Macintosh SE Logic Board Schematic]]
| [[File:MacintoshSE30_AnalogBoard.png|thumb|center|250px|Macintosh SE Analog Board]][[File:Fan, CRT Board.jpg|center|thumb|Macintosh SE Analog Board Schematic]]
| [[File:MacintoshSE30_AnalogBoard.png|thumb|center|300px|Macintosh SE Analog Board]][[File:Fan, CRT Board.jpg|center|thumb|300px|Macintosh SE Analog Board Schematic]]
|}
|}


== Capacitor Replacement Guide ==
== Capacitor Replacement Guide ==
A complete guide to replacing capacitors on the SE's analog and logic boards is available on the [[Macintosh SE Capacitor Replacement Guide]] page.
Electrolytic capacitor degradation is common in SE systems. Specifications and replacement procedures are documented on the [[Macintosh SE Capacitor Replacement Guide]] page.
 
== Retrobrite ==
{{Main|Retrobrite}}The SE's Snow White design plastic yellows from UV exposure. Restoration techniques using hydrogen peroxide treatments are detailed on the [[Retrobrite]] page.
 
== Troubleshooting ==
Simasimac patterns, Sad Mac errors, floppy drive failures, and analog board problems are covered in the [[Macintosh SE Troubleshooting]] guide.
 
== Technical Details ==
<templatestyles src="Template:StyledTable/styles.css" />
 
=== System Architecture ===
{| class="wikitable styled-table" style="width:90%; text-align:center;"
! Sub-system !! Specification (Macintosh SE, March 1987)
|-
| '''CPU''' || Motorola 68000 @ 7.8336 MHz (15.6672 MHz ÷ 2)
|-
| '''Bus width''' || 16-bit data • 24-bit address (16 MB addressable space)
|-
| '''ROM''' || '''256 KB "II-class"''' ROM – QuickDraw 1.2, ADB support, SCSI Manager 2.0
|-
| '''RAM''' || 1 MB standard (4 × 256 KB 30-pin SIMMs) – '''expandable to 4 MB'''
|-
| '''Video''' || 512 × 342 monochrome bitmap (21,888 bytes frame buffer) • 60.15 Hz refresh
|-
| '''Sound''' || 8-bit PWM DAC via VIA Port A • 22.254 kHz sample rate • monaural output
|-
| '''Storage''' || 800 KB Sony double-sided floppy (FDHD: 1.44 MB SuperDrive) • Optional 20/40 MB SCSI
|-
| '''I/O Ports''' || ADB × 2 • DB-19 ext. floppy • DB-25 SCSI • Mini-DIN-8 serial × 2 • 3.5mm audio
|-
| '''Expansion''' || '''SE PDS''' (Processor Direct Slot) – 96-pin Euro-DIN, full 68000 bus access
|}
 
=== Memory Map (Physical) ===
{| class="wikitable styled-table" style="width:80%; text-align:center;"
|+'''Macintosh SE Address Space'''
! Range !! Size !! Purpose
|-
| $000000 – $3FFFFF || 4 MB || '''System RAM''' (1-4 MB populated via SIMMs)
|-
| $400000 – $43FFFF || 256 KB || '''System ROM''' (v5.3 for 800K, v5.5 for FDHD)
|-
| $580000 – $5FFFFF || 512 KB || '''SCSI controller space''' (NCR 5380)
|-
| $900000 – $9FFFFF || 1 MB || '''SCC Read''' (Z8530 serial controller)
|-
| $B00000 – $BFFFFF || 1 MB || '''SCC Write'''
|-
| $C00000 – $CFDFFF || ~1 MB || '''IWM/SWIM''' floppy controller
|-
| $D00000 – $DFFFFF || 1 MB || '''Expansion ROM space''' (PDS cards)
|-
| $E00000 – $E7FFFF || 512 KB || '''VIA space''' (system control)
|-
| $F00000 – $F8FFFF || 576 KB || '''Phase Read''' (memory timing)
|}


[[File:MacintoshSE_CapacitorLocations.jpg|thumb|Capacitor replacement locations placeholder]]
'''Frame buffer location:''' Last 21,888 bytes of installed RAM (e.g., $FF5700-$FFAFFF in 1 MB system)


== Retrobrite ==
=== ROM Versions & Features ===
The SE’s case is prone to yellowing with age. Techniques for restoring the original beige color using Retrobrite methods are covered in detail on the [[Retrobrite]] page.
{| class="wikitable styled-table" style="width:90%;"
! Version !! Size !! Release !! Key Features
|-
| v5.3 || 256 KB || Mar 1987 || Original SE ROM, IWM support, ADB drivers
|-
| v5.4 || 256 KB || Dec 1987 || Bug fixes, improved SCSI handling
|-
| v5.5 || 256 KB || Aug 1989 || SWIM support for FDHD, System 6.0.3+ required
|-
| v5.6 || 256 KB || Late 1989 || Final SE ROM, SuperDrive branding updates
|}
 
=== Custom Chips & ASICs ===
{| class="wikitable styled-table" style="width:90%; text-align:center;"
! Chip !! Function !! Details
|-
| '''BBU''' || Bob Bailey Unit || VLSI custom chip for memory control, DRAM refresh, video timing
|-
| '''GLU''' || General Logic Unit || HAL16L8 PAL, handles address decoding and glue logic
|-
| '''IWM/SWIM''' || Floppy controller || IWM (800K models) or SWIM (FDHD models)
|-
| '''NCR 5380''' || SCSI controller || 8-bit asynchronous SCSI-1, programmed I/O
|-
| '''Z8530 SCC''' || Serial controller || Dual-channel RS-422, up to 230.4 kbps
|-
| '''6522 VIA × 2''' || System control || Timers, interrupts, sound, ADB communication
|-
| '''MC68000''' || Main CPU || 7.8336 MHz, 16-bit data bus, 24-bit addressing
|}
 
=== SE PDS (Processor Direct Slot) ===
The 96-pin Euro-DIN connector provides direct access to the 68000 processor bus.
 
'''Common PDS cards:'''
* '''Radius Full Page Display''' – External monochrome monitor support
* '''Daystar Digital PowerCache''' – 68030 accelerator cards (16-50 MHz)
* '''Asanté MacCon''' – Ethernet networking
* '''Radius Accelerator 16/25''' – 68020 upgrade with FPU socket
 
'''PDS Specifications:'''
* Full 24-bit address bus access
* 16-bit data bus
* Interrupt lines (IPL0-IPL2)
* Bus control signals (AS, DS, R/W)
* +5V, +12V, -12V power rails
* Maximum 16 MB/s theoretical bandwidth
 
=== Floppy Drive Systems ===
 
==== 800K Drive (IWM-based) ====
* '''Sony OA-D34V-22''' mechanism
* Variable speed rotation (394-590 RPM)
* GCR encoding, 80 tracks, 8-12 sectors/track
* 400 KB (single-sided) and 800 KB (double-sided) support
* '''IWM chip''' provides low-level disk control
 
==== 1.44 MB SuperDrive (SWIM-based) ====
* '''Sony MPF-75W''' mechanism
* Constant 300 RPM rotation for HD disks
* MFM encoding for 1.44 MB capacity
* Maintains GCR support for 400/800 KB disks
* '''SWIM chip''' adds MFM encoding/decoding capability
* PC disk compatibility with appropriate software
 
=== Audio System ===
The SE generates sound using the classic Mac architecture:
# CPU writes 8-bit samples to VIA Port A at 22.254 kHz
# VIA Timer 1 creates PWM signal on Port B
# RC filter (R=47kΩ, C=0.01µF) smooths PWM to analog
# Optional amplification through expansion cards
# Output via internal speaker or rear 3.5mm jack
 
=== Power Specifications ===
* '''Input:''' 100-240V AC, 50-60 Hz (auto-switching)
* '''Power consumption:''' 100W typical, 150W maximum
* '''Internal voltages:''' +5V (logic), ±12V (drives/serial), +170V (CRT)
 
=== Environmental Specifications ===
* '''Operating temperature:''' 10°C to 40°C (50°F to 104°F)
* '''Storage temperature:''' -40°C to 47°C (-40°F to 116.6°F)
* '''Relative humidity:''' 5% to 95% non-condensing
 
== FDHD Upgrade Path ==
 
Owners of original 800K SE models could upgrade to FDHD capability with:
 
# '''ROM replacement''' – Three ROM chips (Hi, Lo, and third ROM)
# '''SWIM chip installation''' – Replaces IWM chip at location IWM1
# '''SuperDrive installation''' – Sony MPF-75W mechanism
# '''System software update''' – Minimum System 6.0.3
 
The upgrade maintained backward compatibility while adding:
* 1.44 MB high-density disk support
* MS-DOS disk reading/writing capability
* Improved disk I/O performance
* Support for System 7 features
 
== Historical Context ==
 
The Macintosh SE introduced several technical changes:
 
* '''First compact Mac with internal expansion''' – PDS slot for accelerators and video cards
* '''First compact Mac with a fan''' – Added despite Jobs' preference for fanless operation
* '''Last 68000-based compact Mac''' – Succeeded by the 68030-based SE/30
* '''Transition to ADB''' – Replaced proprietary keyboard/mouse connectors
* '''Introduction of Snow White design''' – Industrial design language used through the 1990s
 
Production estimates indicate approximately '''1.5 million units''' sold worldwide.
 
== Known Issues & Quirks ==
 
* '''Early fan noise complaints''' – December 1987 quieter fan retrofit available
* '''Analog board solder joints''' – Prone to cracking near flyback transformer
* '''2-chip SIMM incompatibility''' – SE requires 8- or 9-chip SIMMs
* '''SCSI termination''' – Internal drives often improperly terminated
* '''ROM Easter Egg''' – Four photos of development team at address $41D89A


[[File:MacintoshSE_Retrobrite.jpg|thumb|Retrobrite process before/after (placeholder)]]
== Maintenance Resources ==
* [[Macintosh SE General Maintenance]] – Cleaning and preventive care
* [[Macintosh SE Capacitor Replacement Guide]] – Capacitor specifications
* [[Macintosh SE Troubleshooting]] – Diagnostic procedures and fixes
* [[CRT Discharge Procedure]] – Safety for internal work
* [[Retrobrite]] – Case restoration techniques


== Troubleshooting ==
== Related Pages ==
For help with issues like boot failures, floppy disk errors, video distortion, and logic board faults, refer to the comprehensive [[Macintosh SE Troubleshooting]] page.
* [[Macintosh Plus]] – Direct predecessor
* [[Macintosh SE/30]] – Enhanced successor with 68030
* [[Macintosh Classic]] – Budget-oriented replacement
* [[Apple Desktop Bus]] – Peripheral connection standard


[[Category:Apple Vintage Computers]]
[[Category:Apple Vintage Computers]]
{{Navbox-AppleVintage}}

Latest revision as of 22:39, 3 September 2025

Macintosh SE
Macintosh SE
Specifications
ManufacturerApple Computer, Inc.
TypePersonal Computer
ReleasedMarch 2, 1987
DiscontinuedOctober 15, 1990
Intro priceUS$2,898 (dual floppy) – $3,898 (with 20MB HD)
CPUMotorola 68000 @ 7.8336 MHz
Memory1 MB RAM (expandable to 4 MB)
Storage800 KB or 1.44 MB floppy drive, optional 20-40 MB SCSI hard drive
Display9" monochrome CRT (512×342 pixels)
SoundMonaural 8-bit, 22.254 kHz
Dimensions13.6" H × 9.6" W × 10.9" D (345 × 244 × 277 mm)
Weight17 lbs (7.7 kg)
OS / FirmwareSystem 4.0 – System 7.5.5
PredecessorMacintosh Plus
SuccessorMacintosh SE/30, Macintosh Classic
CodenamePlusPlus, Aladdin, Chablis, Freeport
Model no.M5010 (800K), M5011 (FDHD)

The Macintosh SE (System Expansion) was introduced on March 2, 1987, alongside the Macintosh II. The SE added an internal expansion slot (PDS), cooling fan, support for internal SCSI hard drives, and Apple Desktop Bus (ADB) for peripherals. Configurations ranged from dual 800 KB floppy drives to combinations with 20 MB or 40 MB internal hard drives.

Model Variants

[edit | edit source]

The Macintosh SE was produced from 1987 to 1990 in several configurations:

Original SE Models (1987-1989)

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  • Macintosh SE Dual Floppy – Two internal 800 KB floppy drives, no hard drive
  • Macintosh SE 1/20 – One 800 KB floppy drive, 20 MB internal SCSI hard drive
  • Macintosh SE 1/40 – One 800 KB floppy drive, 40 MB internal SCSI hard drive

Original SE models used the IWM (Integrated Woz Machine) floppy controller chip and were limited to 800 KB double-sided floppy disks.

Macintosh SE FDHD (1989-1990)

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Macintosh SE FDHD with "FDHD" marking on front panel

In August 1989, Apple introduced the Macintosh SE FDHD (Floppy Disk High Density), which supported 1.44 MB high-density floppy disks. The FDHD model included:

  • SWIM chip (Super Woz Integrated Machine) replacing the IWM controller
  • Updated ROM (minimum System 6.0.3 required) with SWIM driver support
  • Sony MPF-75W SuperDrive mechanism supporting 1.44 MB MFM-encoded disks
  • Backward compatibility with 400 KB and 800 KB Macintosh disks
  • PC Exchange compatibility – ability to read/write MS-DOS formatted disks

The FDHD upgrade was available as a dealer-installed kit (including ROMs, SWIM chip, and drive) for existing SE owners at US$699. In late 1989, Apple renamed the SE FDHD to Macintosh SE SuperDrive, though the hardware remained identical.

General Maintenance

[edit | edit source]

Cleaning procedures, PRAM battery management, connector maintenance, and preventive care are documented in Macintosh SE General Maintenance.

PCB Schematics & Service Manual

[edit | edit source]

The Macintosh SE consists of two primary circuit boards:

Logic Board

[edit | edit source]

The SE logic board used two custom VLSI chips that replaced the six PAL chips from earlier models:

  • BBU (Bob Bailey Unit) – VLSI custom chip for memory management
  • GLU (General Logic Unit) – HAL16L8 PAL replacement handling glue logic and bus arbitration

Analog Board

[edit | edit source]

The analog board provides power regulation, CRT drive circuits, and video amplification. Components include the flyback transformer, voltage regulators, and deflection circuits.

Apple Service Manual

[edit | edit source]

Service documentation is available on the Apple Service Source page.

Logic Board & Analog Board Schematics

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Macintosh SE PCB Schematics
Logic Board Analog Board
Macintosh SE Logic Board
Macintosh SE Logic Board Schematic
Macintosh SE Analog Board
Macintosh SE Analog Board Schematic

Capacitor Replacement Guide

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Electrolytic capacitor degradation is common in SE systems. Specifications and replacement procedures are documented on the Macintosh SE Capacitor Replacement Guide page.

Retrobrite

[edit | edit source]
Main article: Retrobrite

The SE's Snow White design plastic yellows from UV exposure. Restoration techniques using hydrogen peroxide treatments are detailed on the Retrobrite page.

Troubleshooting

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Simasimac patterns, Sad Mac errors, floppy drive failures, and analog board problems are covered in the Macintosh SE Troubleshooting guide.

Technical Details

[edit | edit source]

System Architecture

[edit | edit source]
Sub-system Specification (Macintosh SE, March 1987)
CPU Motorola 68000 @ 7.8336 MHz (15.6672 MHz ÷ 2)
Bus width 16-bit data • 24-bit address (16 MB addressable space)
ROM 256 KB "II-class" ROM – QuickDraw 1.2, ADB support, SCSI Manager 2.0
RAM 1 MB standard (4 × 256 KB 30-pin SIMMs) – expandable to 4 MB
Video 512 × 342 monochrome bitmap (21,888 bytes frame buffer) • 60.15 Hz refresh
Sound 8-bit PWM DAC via VIA Port A • 22.254 kHz sample rate • monaural output
Storage 800 KB Sony double-sided floppy (FDHD: 1.44 MB SuperDrive) • Optional 20/40 MB SCSI
I/O Ports ADB × 2 • DB-19 ext. floppy • DB-25 SCSI • Mini-DIN-8 serial × 2 • 3.5mm audio
Expansion SE PDS (Processor Direct Slot) – 96-pin Euro-DIN, full 68000 bus access

Memory Map (Physical)

[edit | edit source]
Macintosh SE Address Space
Range Size Purpose
$000000 – $3FFFFF 4 MB System RAM (1-4 MB populated via SIMMs)
$400000 – $43FFFF 256 KB System ROM (v5.3 for 800K, v5.5 for FDHD)
$580000 – $5FFFFF 512 KB SCSI controller space (NCR 5380)
$900000 – $9FFFFF 1 MB SCC Read (Z8530 serial controller)
$B00000 – $BFFFFF 1 MB SCC Write
$C00000 – $CFDFFF ~1 MB IWM/SWIM floppy controller
$D00000 – $DFFFFF 1 MB Expansion ROM space (PDS cards)
$E00000 – $E7FFFF 512 KB VIA space (system control)
$F00000 – $F8FFFF 576 KB Phase Read (memory timing)

Frame buffer location: Last 21,888 bytes of installed RAM (e.g., $FF5700-$FFAFFF in 1 MB system)

ROM Versions & Features

[edit | edit source]
Version Size Release Key Features
v5.3 256 KB Mar 1987 Original SE ROM, IWM support, ADB drivers
v5.4 256 KB Dec 1987 Bug fixes, improved SCSI handling
v5.5 256 KB Aug 1989 SWIM support for FDHD, System 6.0.3+ required
v5.6 256 KB Late 1989 Final SE ROM, SuperDrive branding updates

Custom Chips & ASICs

[edit | edit source]
Chip Function Details
BBU Bob Bailey Unit VLSI custom chip for memory control, DRAM refresh, video timing
GLU General Logic Unit HAL16L8 PAL, handles address decoding and glue logic
IWM/SWIM Floppy controller IWM (800K models) or SWIM (FDHD models)
NCR 5380 SCSI controller 8-bit asynchronous SCSI-1, programmed I/O
Z8530 SCC Serial controller Dual-channel RS-422, up to 230.4 kbps
6522 VIA × 2 System control Timers, interrupts, sound, ADB communication
MC68000 Main CPU 7.8336 MHz, 16-bit data bus, 24-bit addressing

SE PDS (Processor Direct Slot)

[edit | edit source]

The 96-pin Euro-DIN connector provides direct access to the 68000 processor bus.

Common PDS cards:

  • Radius Full Page Display – External monochrome monitor support
  • Daystar Digital PowerCache – 68030 accelerator cards (16-50 MHz)
  • Asanté MacCon – Ethernet networking
  • Radius Accelerator 16/25 – 68020 upgrade with FPU socket

PDS Specifications:

  • Full 24-bit address bus access
  • 16-bit data bus
  • Interrupt lines (IPL0-IPL2)
  • Bus control signals (AS, DS, R/W)
  • +5V, +12V, -12V power rails
  • Maximum 16 MB/s theoretical bandwidth

Floppy Drive Systems

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800K Drive (IWM-based)

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  • Sony OA-D34V-22 mechanism
  • Variable speed rotation (394-590 RPM)
  • GCR encoding, 80 tracks, 8-12 sectors/track
  • 400 KB (single-sided) and 800 KB (double-sided) support
  • IWM chip provides low-level disk control

1.44 MB SuperDrive (SWIM-based)

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  • Sony MPF-75W mechanism
  • Constant 300 RPM rotation for HD disks
  • MFM encoding for 1.44 MB capacity
  • Maintains GCR support for 400/800 KB disks
  • SWIM chip adds MFM encoding/decoding capability
  • PC disk compatibility with appropriate software

Audio System

[edit | edit source]

The SE generates sound using the classic Mac architecture:

  1. CPU writes 8-bit samples to VIA Port A at 22.254 kHz
  2. VIA Timer 1 creates PWM signal on Port B
  3. RC filter (R=47kΩ, C=0.01µF) smooths PWM to analog
  4. Optional amplification through expansion cards
  5. Output via internal speaker or rear 3.5mm jack

Power Specifications

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  • Input: 100-240V AC, 50-60 Hz (auto-switching)
  • Power consumption: 100W typical, 150W maximum
  • Internal voltages: +5V (logic), ±12V (drives/serial), +170V (CRT)

Environmental Specifications

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  • Operating temperature: 10°C to 40°C (50°F to 104°F)
  • Storage temperature: -40°C to 47°C (-40°F to 116.6°F)
  • Relative humidity: 5% to 95% non-condensing

FDHD Upgrade Path

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Owners of original 800K SE models could upgrade to FDHD capability with:

  1. ROM replacement – Three ROM chips (Hi, Lo, and third ROM)
  2. SWIM chip installation – Replaces IWM chip at location IWM1
  3. SuperDrive installation – Sony MPF-75W mechanism
  4. System software update – Minimum System 6.0.3

The upgrade maintained backward compatibility while adding:

  • 1.44 MB high-density disk support
  • MS-DOS disk reading/writing capability
  • Improved disk I/O performance
  • Support for System 7 features

Historical Context

[edit | edit source]

The Macintosh SE introduced several technical changes:

  • First compact Mac with internal expansion – PDS slot for accelerators and video cards
  • First compact Mac with a fan – Added despite Jobs' preference for fanless operation
  • Last 68000-based compact Mac – Succeeded by the 68030-based SE/30
  • Transition to ADB – Replaced proprietary keyboard/mouse connectors
  • Introduction of Snow White design – Industrial design language used through the 1990s

Production estimates indicate approximately 1.5 million units sold worldwide.

Known Issues & Quirks

[edit | edit source]
  • Early fan noise complaints – December 1987 quieter fan retrofit available
  • Analog board solder joints – Prone to cracking near flyback transformer
  • 2-chip SIMM incompatibility – SE requires 8- or 9-chip SIMMs
  • SCSI termination – Internal drives often improperly terminated
  • ROM Easter Egg – Four photos of development team at address $41D89A

Maintenance Resources

[edit | edit source]
[edit | edit source]
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