Macintosh IIsi
 | |
| Macintosh IIsi | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Desktop Personal Computer |
| Released | October 15, 1990 |
| Discontinued | March 15, 1993 |
| Intro price | US$2,999 – $3,770 |
| CPU | Motorola 68030 @ 20 MHz |
| Memory | 1 MB RAM soldered (expandable to 17 MB) |
| Storage | 40 MB, 80 MB, or 160 MB SCSI hard drive |
| Display | Integrated video (640×480 @ 8-bit color) |
| Sound | 8-bit stereo output, 8-bit mono input |
| Dimensions | 4.0" H × 12.4" W × 14.9" D (10.2 × 31.5 × 37.8 cm) |
| Weight | 10 lbs (4.5 kg) |
| OS / Firmware | System 6.0.7 – Mac OS 7.6.1 |
| Predecessor | Macintosh IIci |
| Successor | Macintosh Centris 610 |
| Codename | Erickson, Raffica, Ray Ban, Spin, Oceanic |
| Model no. | M0360 |
The Macintosh IIsi is a desktop personal computer designed, manufactured, and sold by Apple Computer, Inc. from October 1990 to March 1993.[1] Introduced as a lower-cost alternative to the Macintosh IIci, the IIsi was Apple's entry-level professional Macintosh, with more expandability than the Macintosh LC which launched the same day.[2]
The IIsi was the first Macintosh with built-in audio recording, featuring an integrated microphone input.[3] The compact desktop case was unique to the IIsi and not used for any other Macintosh model.
Architecture and Processor
[edit | edit source]The Macintosh IIsi uses a Motorola MC68030 microprocessor running at 20 MHz.[4]
- 32-bit internal registers with 32-bit data path
- 24-bit or 32-bit addressing modes
- 0.5 KB Level 1 cache (on-chip)
- No Level 2 cache
The system bus runs at 20 MHz. Apple underclocked the IIsi from 25 MHz to 20 MHz to avoid cannibalizing sales of the more expensive IIci. Many users modified ("chipped") their IIsi to run at 25 MHz or 28 MHz.[5]
Floating Point Unit
[edit | edit source]The Motorola 68882 FPU is optional and not included on the logic board. The FPU installs via the Apple NuBus Adapter card, which plugs into the Processor Direct Slot and converts it to a NuBus slot while providing the FPU socket.[6]
Memory
[edit | edit source]RAM Configuration
[edit | edit source]- Soldered RAM: 1 MB on logic board
- SIMM Slots: 4 × 30-pin SIMM slots
- SIMM Speed: 100 ns minimum
- Maximum RAM: 17 MB (Apple official), 65 MB (with unofficial 16 MB SIMMs)
- SIMM Installation: Must be installed in matched groups of four identical SIMMs
- Supported SIMM Sizes: 256 KB, 512 KB, 1 MB, 2 MB, 4 MB (8 MB and 16 MB SIMMs work but are not officially supported)
The IIsi's 1 MB of soldered RAM cannot be removed or disabled. When calculating total RAM, add this 1 MB to the SIMM capacity.[7]
ROM
[edit | edit source]- ROM Size: 512 KB
- ROM Type: Usually soldered to the logic board
- ROM SIMM Slot: Present on some units; may contain a ROM SIMM instead of soldered ROMs
- ROM ID: $067C
Some IIsi units shipped with ROMs on a removable SIMM rather than soldered chips. The IIsi ROM is reportedly compatible with the Macintosh SE/30 and may provide 32-bit clean operation when installed.[8]
Video
[edit | edit source]The Macintosh IIsi uses integrated video that shares main system RAM, reducing available RAM and impacting performance.[9]
Video Specifications
[edit | edit source]- Video Output: DB-15 connector
- Video RAM: 64 KB – 320 KB (shared from system RAM, depending on resolution)
- Maximum Resolution: 640 × 480 pixels
- Color Depth: 8-bit (256 colors) at 640 × 480
- Portrait Monitor Support: 640 × 870 at 4-bit (16 grays)
Video uses the slow 1 MB of soldered RAM first, making video performance slower than dedicated VRAM systems. Setting the disk cache to 768 KB or larger forces video operations to use the faster SIMM RAM instead.[10]
Audio
[edit | edit source]The Macintosh IIsi was the first Macintosh with built-in audio input.[11]
- Audio Output: 8-bit stereo, 22 kHz
- Audio Input: 8-bit mono, omnidirectional microphone input
- Output Jack: 3.5 mm stereo headphone jack
- Input Jack: 3.5 mm microphone input
- Internal Speaker: Mono speaker on daughterboard
The IIsi develops sound issues over time due to its modular construction. The internal speaker mounts on a daughterboard with spring contacts that connect to the logic board. Speaker vibrations cause fretting of the contact surfaces, resulting in intermittent audio dropouts. Cleaning the contacts with a pencil eraser fixes this.[12]
Storage
[edit | edit source]Hard Drive
[edit | edit source]- Interface: SCSI (DB-25 external connector)
- Standard Capacities: 40 MB, 80 MB, or 160 MB
- Internal Bay: One 3.5" SCSI hard drive bay
Floppy Drive
[edit | edit source]- Drive Type: Apple SuperDrive (1.44 MB)
- Floppy Capacity: 1.44 MB (HD) and 800 KB (DD)
- Injection Type: Auto-inject
- External Connector: DB-19 floppy port
Input/Output and Expansion
[edit | edit source]Ports
[edit | edit source]- ADB Ports: 1 (Apple Desktop Bus for keyboard and mouse)
- Serial Ports: 2 × Mini DIN-8 RS-422 (Printer and Modem)
- SCSI Port: DB-25 connector
- Floppy Port: DB-19 connector
- Video Port: DB-15 connector
- Audio Output: 3.5 mm stereo jack
- Audio Input: 3.5 mm microphone jack
Expansion Slot
[edit | edit source]The IIsi has a single Processor Direct Slot (PDS) compatible with Macintosh SE/30 expansion cards. The slot runs at 20 MHz instead of 16 MHz, so some SE/30 cards may not work.[13]
The Apple IIsi NuBus Adapter converts the PDS slot to accept standard 7-inch NuBus cards. This adapter also includes a socket for the optional 68882 FPU. With a slim hard drive, 12-inch NuBus cards may also fit.[14]
Power
[edit | edit source]- Power Supply: 160W internal
- Input Voltage: 100V – 240V AC
- Frequency: 50 – 60 Hz
- Maximum Wattage: 160W
- BTU per Hour: 547.2
- PRAM Battery: 3.6V lithium half-AA
- Soft Power: Yes (power controlled via ADB keyboard)
- Pass-Through: Yes (power outlet on back for monitor)
Case Design
[edit | edit source]The IIsi uses a unique compact desktop case not shared with any other Macintosh. The case uses clips and latches rather than screws, requiring no tools for disassembly.[15]
- Dimensions: 4.0" H × 12.4" W × 14.9" D (10.2 × 31.5 × 37.8 cm)
- Weight: 10 lbs (4.5 kg)
General Maintenance
[edit | edit source]Common maintenance concerns include capacitor leakage, PRAM battery failure, and speaker contact corrosion.
For cleaning, battery maintenance, board inspection, and power supply procedures, see the Macintosh IIsi General Maintenance page.
PCB Schematics & Service Manual
[edit | edit source]The Macintosh IIsi has a logic board, power supply, and speaker daughterboard. Apple Service Source documentation provides troubleshooting and repair information.
Apple Service Manual
[edit | edit source]
The complete Apple Service Source manual is at Macintosh IIsi Service Source. Additional manuals are in the Apple Service Source category.
Capacitor Replacement Guide
[edit | edit source]The Macintosh IIsi logic board and power supply contain surface-mount electrolytic capacitors prone to leakage after 30+ years. Leaking capacitors corrode PCB traces and cause intermittent operation.
Logic Board Capacitors:
- 2 × 220 µF 16V (axial electrolytic)
- 11 × 47 µF 16V (surface-mount tantalum)
For capacitor specifications and procedures, see the Macintosh IIsi Capacitor Replacement Guide.[16]
Troubleshooting
[edit | edit source]Common issues include startup failures, video problems, audio dropouts, and SCSI device issues. Many problems are caused by capacitor failure or PRAM battery leakage.
For diagnostics on power, video, Sad Mac errors, sound, and SCSI failures, see the Macintosh IIsi Troubleshooting page.
Technical Specifications
[edit | edit source]System Overview
[edit | edit source]| Sub-system | Specification (Macintosh IIsi, October 1990) |
|---|---|
| CPU | Motorola 68030 @ 20 MHz |
| FPU | Optional Motorola 68882 (via NuBus adapter) |
| Bus Width | 32-bit data • 24-bit or 32-bit addressing |
| ROM | 512 KB |
| RAM | 1 MB soldered + 4 × 30-pin SIMM slots (17 MB max official) |
| L1 Cache | 0.5 KB (on-chip) |
| L2 Cache | None |
| Video | Integrated, 640 × 480 @ 8-bit (shares system RAM) |
| Sound | 8-bit stereo output • 8-bit mono input |
| Storage | 40/80/160 MB SCSI HDD • 1.44 MB SuperDrive |
| Expansion | 1 × SE/30 PDS (convertible to NuBus with adapter) |
| Ports | ADB • 2 × Serial • SCSI • Floppy • Video • Audio I/O |
Model Configurations
[edit | edit source]| Order Number | RAM | Hard Drive | Price (1990) |
|---|---|---|---|
| M0363LL/A | 2 MB | 40 MB | US$2,999 |
| M0364LL/A | 5 MB | 80 MB | US$3,769 |
| M0364LL/B | 5 MB | 80 MB | — |
| M0491LL/B | 3 MB | 40 MB | — |
| M0954LL/A | 5 MB | 160 MB | — |
Identification
[edit | edit source]| Identifier | Value |
|---|---|
| Apple Model Number | M0360 |
| Gestalt ID | 18 |
| ROM ID | $067C |
See Also
[edit | edit source]References
[edit | edit source]- ↑ Macintosh IIsi: Technical Specifications, Apple Inc.—link(accessed 2026-02-09)
- ↑ Macintosh IIsi Specs, EveryMac.com—link(accessed 2026-02-09)
- ↑ Mac IIsi, Low End Mac—link(accessed 2026-02-09)
- ↑ Macintosh IIsi, Wikipedia—link(accessed 2026-02-09)
- ↑ Mac IIsi, Low End Mac—link(accessed 2026-02-09)
- ↑ Macintosh IIsi Specs, EveryMac.com—link(accessed 2026-02-09)
- ↑ Macintosh IIsi: Technical Specifications, Apple Inc.—link(accessed 2026-02-09)
- ↑ Mac IIsi, Low End Mac—link(accessed 2026-02-09)
- ↑ Macintosh IIsi, Wikipedia—link(accessed 2026-02-09)
- ↑ Macintosh IIsi, Wikipedia—link(accessed 2026-02-09)
- ↑ Mac IIsi, Low End Mac—link(accessed 2026-02-09)
- ↑ Macintosh IIsi, Wikipedia—link(accessed 2026-02-09)
- ↑ Mac IIsi, Low End Mac—link(accessed 2026-02-09)
- ↑ Macintosh IIsi Specs, EveryMac.com—link(accessed 2026-02-09)
- ↑ Macintosh IIsi, Wikipedia—link(accessed 2026-02-09)
- ↑ Caps! -- Macintosh IIsi, 68kMLA—link(accessed 2026-02-09)