Macintosh IIx
 | |
| Macintosh IIx | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal computer |
| Released | September 19, 1988 |
| Discontinued | October 15, 1990 |
| Intro price | US$7,769 – $9,369 (with 40 MB HD) |
| CPU | Motorola 68030 @ 16 MHz |
| Memory | 1 MB or 4 MB standard, expandable to 128 MB |
| Storage | Optional 40 MB or 80 MB SCSI hard drive |
| Display | None built-in (requires NuBus graphics card) |
| Sound | 8-bit stereo, 22.254 kHz sampling |
| Dimensions | 5.5" H × 18.5" W × 14.4" D (140 × 470 × 365 mm) |
| Weight | 24 lbs (10.9 kg) |
| OS / Firmware | System 6.0.2 – Mac OS 8.1 (with Mode32) |
| Predecessor | Macintosh II |
| Successor | Macintosh IIfx |
| Codename | Spock, Stratos |
| Model no. | M5810 (1 MB), M5820 (4 MB) |
The Macintosh IIx was introduced on September 19, 1988, as an incremental upgrade to the Macintosh II. The IIx replaced the 16 MHz Motorola 68020 processor with a 68030 running at the same clock speed, added the 68882 FPU as standard, and introduced the 1.44 MB SuperDrive (FDHD) floppy drive. The IIx maintained the same six-slot NuBus architecture and modular case design as its predecessor while adding integrated PMMU support and 256 bytes each of instruction and data cache.
Development & Market Position
[edit | edit source]Apple developed the IIx under the codenames "Spock" and "Stratos" as a straightforward evolution of the Macintosh II architecture. The "x" suffix indicated the presence of the 68030 CPU, a naming convention Apple used across multiple models including the Macintosh IIcx and Macintosh IIvx.
Released at $7,769 for a base configuration or $9,369 with a 40 MB hard drive, the IIx targeted professional users requiring expandability and performance. The machine competed directly with workstations from Sun Microsystems, Silicon Graphics, and Hewlett-Packard. Apple increased the Macintosh II's price by approximately 20% just before the IIx introduction, positioning the new model as a modest upgrade cost.
Model Configurations
[edit | edit source]The IIx was available in several standard configurations:
Base Models
[edit | edit source]- Macintosh IIx 1/0 – 1 MB RAM, dual 1.44 MB floppy drives, no hard drive
- Macintosh IIx 4/0 – 4 MB RAM, dual 1.44 MB floppy drives, no hard drive
- Macintosh IIx 1/40 – 1 MB RAM, one 1.44 MB floppy, 40 MB hard drive
- Macintosh IIx 4/40 – 4 MB RAM, one 1.44 MB floppy, 40 MB hard drive
- Macintosh IIx 4/80 – 4 MB RAM, one 1.44 MB floppy, 80 MB hard drive
All configurations required at least one NuBus graphics card for video output, as the IIx had no built-in video capability.
General Maintenance
[edit | edit source]Power-on circuit repair, battery replacement, capacitor inspection, and cleaning procedures are documented in Macintosh IIx General Maintenance.
PCB Architecture & Service Documentation
[edit | edit source]The IIx consists of a large logic board with integrated I/O and expansion, plus a separate power supply unit:
Logic Board
[edit | edit source]The IIx logic board features:
- Motorola 68030 processor at 16 MHz with integrated MMU
- Motorola 68882 FPU at 16 MHz
- ROM SIMM slot containing required 256 KB ROM
- Eight 30-pin SIMM slots in two banks of four
- Six NuBus slots for expansion cards
- SWIM chip for SuperDrive support
Power Supply
[edit | edit source]The power supply provides:
- +5V, +12V, -12V regulated outputs
- 230W maximum output
- Soft power control via ADB
- Pass-through AC outlet
Apple Service Manual
[edit | edit source]
Service documentation is available on the Apple Service Source page.
Capacitor Replacement Guide
[edit | edit source]Surface-mount electrolytic capacitors on the IIx logic board are prone to leakage after 30+ years. Replacement procedures and specifications are documented on the Macintosh IIx Capacitor Replacement Guide page.
Troubleshooting
[edit | edit source]Power-on failures, chimes of death, NuBus issues, and memory problems are covered in the Macintosh IIx Troubleshooting guide.
Technical Details
[edit | edit source]System Architecture
[edit | edit source]| Sub-system | Specification (Macintosh IIx, September 1988) |
|---|---|
| CPU | Motorola 68030 @ 16 MHz • Integrated PMMU • 256 bytes I-cache + 256 bytes D-cache |
| Bus width | 32-bit data • 32-bit address (4 GB theoretical, 128 MB actual limit) |
| ROM | 256 KB ROM SIMM • "Dirty" ROMs require Mode32 for >8 MB RAM |
| RAM | 1-128 MB via 30-pin SIMMs • Two banks of four slots • 120ns or faster |
| Video | None built-in • Requires NuBus graphics card |
| Sound | Apple Sound Chip (ASC) • 4-voice stereo • 22.254 kHz sampling |
| Storage | 1.44 MB SuperDrive standard • Optional 40/80 MB SCSI hard drive |
| I/O Ports | ADB × 2 • Mini-DIN-8 serial × 2 • DB-25 SCSI • DB-19 floppy |
| Expansion | Six NuBus slots • 10 MHz bus speed • 10-40 MB/s bandwidth |
Memory Configuration
[edit | edit source]The IIx uses eight 30-pin SIMM slots arranged in two banks of four. Both banks must be populated with identical SIMMs within each bank.
| Bank A | Bank B | Total RAM | Notes |
|---|---|---|---|
| 4 × 256 KB | Empty | 1 MB | Minimum configuration |
| 4 × 256 KB | 4 × 256 KB | 2 MB | |
| 4 × 1 MB | Empty | 4 MB | |
| 4 × 1 MB | 4 × 1 MB | 8 MB | Maximum without Mode32 |
| 4 × 4 MB PAL | Empty | 16 MB | Requires Mode32 |
| 4 × 4 MB PAL | 4 × 1 MB | 20 MB | Requires Mode32 |
| 4 × 4 MB PAL | 4 × 4 MB PAL | 32 MB | Requires Mode32 |
| 4 × 16 MB PAL | 4 × 16 MB PAL | 128 MB | Maximum, requires Mode32 |
Important notes:
- 4 MB and 16 MB SIMMs must be PAL (Presence Detect) type
- Mode32 or 32-bit System Enabler required for >8 MB configurations
- Bank A must be populated before Bank B can be used
ROM Specifications
[edit | edit source]The IIx requires a ROM SIMM in the dedicated ROM slot. The ROM is "32-bit dirty," containing 24-bit addressing code that limits RAM access to 8 MB without software patches.
| Version | Size | Features | Limitations |
|---|---|---|---|
| IIx ROM | 256 KB | SWIM support, 68030 optimizations | 32-bit dirty, 8 MB limit without Mode32 |
| IIfx ROM | 512 KB | 32-bit clean alternative | Not officially supported but functional |
NuBus Architecture
[edit | edit source]The six NuBus slots provide the primary expansion capability:
| Parameter | Specification |
|---|---|
| Bus speed | 10 MHz |
| Data width | 32-bit |
| Address space | 256 MB per slot |
| Bandwidth | 10-40 MB/s (theoretical) |
| Slot numbering | 9, A, B, C, D, E (hexadecimal) |
| Power per slot | +5V @ 2A, +12V @ 0.3A, -12V @ 0.3A |
Common NuBus cards:
- Graphics cards – Apple 8•24, Radius DirectColor/GX
- Accelerators – DayStar Digital PowerCache, Radius Rocket
- Network cards – Ethernet, Token Ring adapters
- Video capture – Media Time, VideoSpigot
- Additional I/O – Serial/parallel expansion cards
SuperDrive (FDHD) System
[edit | edit source]The IIx was the first Macintosh II series computer with built-in SuperDrive support:
Technical Specifications
[edit | edit source]- Controller: SWIM (Super Wozniak Integrated Machine) chip
- Capacity: 1.44 MB (high density), 800 KB (double density), 400 KB (single density)
- Encoding: MFM for 1.44 MB, GCR for 400/800 KB
- Compatibility: Mac, ProDOS, MS-DOS formats (with software)
- Transfer rate: Up to 62.5 KB/s
Drive Support Matrix
[edit | edit source]| Drive Type | Internal Support | External Support |
|---|---|---|
| 400 KB | Read only | Read only |
| 800 KB | Full support | Full support |
| 1.44 MB | Full support | Full support |
| MS-DOS 720 KB | With Apple File Exchange | With Apple File Exchange |
| MS-DOS 1.44 MB | With Apple File Exchange | With Apple File Exchange |
SCSI Subsystem
[edit | edit source]The IIx uses the NCR 5380 SCSI controller providing:
- SCSI-1 interface (5 MB/s maximum)
- Seven device support (ID 0-6, Mac is ID 7)
- DB-25 external connector
- 50-pin internal connector
- Asynchronous transfers only
Real-world SCSI performance typically achieves 1.4 MB/s with appropriate drives and proper termination.
Audio System
[edit | edit source]The Apple Sound Chip (ASC) provides enhanced audio capabilities:
- Four-voice wavetable synthesis
- Stereo output via dual 8-bit DACs
- 22.254 kHz standard sampling rate
- 11.127 kHz and 7.418 kHz alternate rates
- 512-byte FIFO buffer per channel
Power Specifications
[edit | edit source]- Input: 100-132V or 198-264V AC, 47-63 Hz (switch selectable)
- Maximum power: 230W
- BTU/hr: 786.6
- Power distribution:
- +5V @ 14.0A
- +12V @ 1.8A
- -12V @ 0.25A
- -5V @ 0.1A
Power-On Circuit
[edit | edit source]The IIx features a complex power-on circuit that requires functioning batteries:
| Component | Function | Common Failure Mode |
|---|---|---|
| Dual 3.6V batteries | Provide 7V for power-on circuit | Dead batteries prevent power-on |
| UB1, UB2 transistors | Switch power supply control | Capacitor leakage damages transistors |
| C5, C6 capacitors | Filter power-on circuit | Leakage breaks nearby traces |
| R3, R18 resistors | Current limiting | Corrosion from capacitor leakage |
Without functioning batteries or with damaged power-on components, the IIx cannot start via the rear power button or ADB power key.
32-bit Addressing & Mode32
[edit | edit source]The IIx ships with "32-bit dirty" ROMs containing residual 24-bit code. This limits usable RAM to 8 MB regardless of physical installation. To access more than 8 MB:
Software Solutions
[edit | edit source]- Mode32 1.2 – For System 7.0/7.1
- Mode32 7.5 – For System 7.5.x
- 32-bit System Enabler – Apple's solution (less stable than Mode32)
- System 7.6 – Requires 32-bit clean ROMs (not compatible)
Installation Process
[edit | edit source]- Install physical RAM beyond 8 MB
- Install Mode32 in System Folder
- Open Memory control panel
- Check "32-bit Addressing"
- Restart
Known Issues & Solutions
[edit | edit source]Power-On Failures
[edit | edit source]- No response to power button – Dead batteries or damaged power-on circuit
- Powers on via ADB only – UB1/UB2 transistor failure
- Clicking/ticking sound – Power supply protection, check for shorts
Memory Issues
[edit | edit source]- Only recognizes 8 MB – Install Mode32 and enable 32-bit addressing
- Chimes of death – Reseat SIMMs, verify matched sets
- Random crashes – Replace PAL SIMMs with correct type
Video Problems
[edit | edit source]- No video output – Verify NuBus card seated properly
- Grayscale only – Check monitor sense pins on video cable
- Distorted display – Clean NuBus contacts with contact cleaner
SCSI Issues
[edit | edit source]- Devices not recognized – Check termination and cable quality
- Slow performance – Verify proper termination at chain ends
- System hangs at startup – Remove all SCSI devices, test individually
Upgrade Paths
[edit | edit source]Processor Upgrades
[edit | edit source]- DayStar Digital PowerCache – 33/40/50 MHz 68030 accelerators
- Radius Rocket – 68040-based NuBus coprocessor cards
Video Upgrades
[edit | edit source]- Apple 8•24 GC – Accelerated 24-bit graphics
- Radius DirectColor/GX – High-performance graphics
- SuperMac Thunder/24 – 24-bit accelerated video
Storage Upgrades
[edit | edit source]- Larger SCSI drives – Up to 2 GB supported natively
- SCSI-2 cards – DayStar Digital SCSI PowerCard for faster transfers
Historical Context
[edit | edit source]The IIx served as Apple's high-end workstation from September 1988 until the Macintosh IIfx introduction in March 1990. Notable uses included:
- Industrial Light & Magic for "The Abyss" image processing
- Publishing industry for early desktop publishing
- Scientific computing with FPU-intensive applications
- CAD/CAM workstation applications
Production ceased October 15, 1990, after approximately 80,000 units sold. Support and spare parts were discontinued August 31, 1998.
Maintenance Resources
[edit | edit source]- Macintosh IIx General Maintenance – Cleaning and battery service
- Macintosh IIx Capacitor Replacement Guide – Capacitor specifications
- Macintosh IIx Troubleshooting – Diagnostic procedures
- NuBus Card Guide – Expansion card information
- SCSI Configuration Guide – Termination and setup
Related Pages
[edit | edit source]- Macintosh II – Direct predecessor
- Macintosh IIfx – High-performance successor
- Macintosh IIcx – Compact three-slot variant
- Macintosh IIci – Built-in video successor
- Mode32 – 32-bit addressing enabler