Macintosh Classic II
The Macintosh Classic II, released in 1991, was the final compact black-and-white Macintosh to use the classic all-in-one design. Unlike its predecessor, it utilized the more advanced Motorola 68030 processor—similar to the SE/30—but without the PDS expansion slot or 32-bit clean ROM. It came with 2 MB of RAM standard and supported up to 10 MB via a single 100 ns 30-pin SIMM. The Classic II retained the 9-inch monochrome display, making it ideal for schools and business use, but with improved performance and more modern architecture.
 | |
| Macintosh Classic II | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 21, 1991 |
| Discontinued | September 13, 1993 |
| Intro price | US$1,900 |
| CPU | Motorola 68030 @ 16 MHz |
| Memory | 2 MB RAM (expandable to 10 MB) |
| Storage | 1.44 MB 3.5" floppy drive, optional 40–80 MB SCSI hard drive |
| Display | 9" monochrome CRT (512×342 pixels) |
| Sound | Monaural 8-bit, 22 kHz |
| Dimensions | 13.2" H × 9.6" W × 10.9" D |
| Weight | 16.5 lbs (7.5 kg) |
| OS / Firmware | System 6.0.8L – System 7.6.1 |
| Predecessor | Macintosh Classic |
| Successor | Macintosh Color Classic |
| Codename | Performa, Stardust, Apollo |
| Model no. | M0420, M4150 |
General Maintenance
Due to the similarities witth the Macintosh Classic, for details on disassembly, cleaning, voltage regulation, PRAM battery handling, and corrosion prevention, refer to the Macintosh Classic / Classic II General Maintenance page.
PCB Schematics & Service Manual
The Classic II consists of a logic board and analog board, similar in layout to the Macintosh SE/30 but with different ICs and no expansion slot. The analog board for the Classic II is identical to the Macintosh Classic. However, the logic board in the Classic II has a complete redesign.
Apple Service Manual
All Apple Service Manuals can be found on the Apple Service Source page.
Logic Board & Analog Board Schematics
| Logic Board | Analog Board |
|---|---|
 |
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Capacitor Replacement Guide
The Classic II is prone to logic board failure due to surface-mount capacitor leakage. For safe replacement procedures, refer to the Macintosh Classic II Capacitor Replacement Guide.
Retrobrite
For plastic restoration and case whitening instructions, visit the Retrobrite page.
Troubleshooting
A complete guide to common issues including no chime, no video, checkerboard pattern, logic board failure, and hard drive detection issues is available at the Macintosh Classic / Classic II Troubleshooting page.
Technical Details
System Architecture at a Glance
| Sub-system | Specification (Macintosh Classic II / Performa 200, Oct 1991) |
|---|---|
| CPU | Motorola 68030 @ 16.67 MHz (33.33 MHz ÷ 2)
|
| FPU | — (none; 68882 socket removed to cut cost) |
| Chipset | “V8 Lite” ASIC (MEMCjr + I/O GLU) handles DRAM, video DMA, VIA timers |
| ROM | 512 KB “IIci-class” ROM SIMM (v7.1) — Color QD 1.3, 32-bit clean, SCSI Mgr 4.3 |
| RAM (base) | 2 MB soldered (8 × 256 K × 4 DRAM, 100 ns) |
| RAM (slots) | 2 × 30-pin SIMM — accepts 256 KB, 1 MB, 4 MB (80 ns)
Max = 10 MB (2 MB on-board + 2 × 4 MB) |
| Video | 512 × 342 mono (22.1 KB) DMA-steals from main DRAM
VRAM “page” is dual-ported inside MEMCjr |
| Sound | 8-bit PWM DAC via VIA Timer-1 • 22 kHz → RC filter → LM380 amp |
| Storage | Internal Apple FDHD 1.44 MB (SWIM-II) • 40–160 MB 2.5″ SCSI HDD |
| Ports | ADB • DB-19 ext floppy • DB-25 SCSI-1 • RS-422 serial × 2 • 3.5 mm audio-out |
| Expansion | No PDS; logic-board edge exposes debug pads only. |
Physical Memory Map
| Range (hex) | Size | Purpose |
|---|---|---|
| $0000 00 – $1FFF FF | 2 MB | On-board DRAM (base memory) |
| $2000 00 – $9FFF FF | 8 MB | SIMM DRAM banks (if present) |
| $4000 00 – $47FF FF | 512 KB | ROM SIMM (v7.1) |
| $5000 00 – $50FF FF | 64 KB | I/O Bank A — VIA-1/2, SCC, SWIM-II, V8 Lite, Egret |
| $5800 00 – $58FF FF | 64 KB | NCR 53C96 SCSI + glue |
| $5C00 00 – $5FFF FF | 256 KB | Unused / test decode |
| $9000 00 – $9000 FF | 256 B | Video shift register (mirrored) |
| $C000 00 – $FF FF FF | Mirror / reserved |
- Frame-buffer:* 22,016-byte screen bitmap sits at top of total DRAM (e.g. $9FE000–$9FFFFF in a 10 MB system).
ROM SIMM Breakdown (512 KB, v7.1)
| Offset | Size | Module |
|---|---|---|
| $4000 00 | 16 KB | 68030 vectors + micro-shell |
| $4004 00 | 64 KB | Color / Mono QuickDraw 1.3 (32-bit) |
| $4014 00 | 192 KB | Toolbox, Window/Menu mgrs., SANE FP |
| $4044 00 | 80 KB | SWIM-II, ASC 8-bit audio, Egret ADB |
| $405E 00 | 96 KB | SCSI Mgr 4.3, Disk Cache, HFS/HFS+ |
Key Silicon & I/O Devices
- MEMCjr / V8 Lite ASIC — DRAM controller, 68030 bus mux, video DMA, VIA handshake
- 6522 VIA × 2 — timers, sound PWM, keyboard latch
- 8530 SCC — dual RS-422 serial (GeoPort ready)
- SWIM-II — GCR/MFM floppy (800 KB & 1.44 MB)
- NCR 53C96 — fast SCSI, 8-bit DMA style
- Egret 68HC05 — ADB host, PRAM, soft-power, real-time clock
DRAM & SIMM Configuration
| Total RAM | On-board | SIMM 1 | SIMM 2 | Notes |
|---|---|---|---|---|
| 2 MB | 2 MB | — | — | Base model |
| 4 MB | 2 MB | 1 MB | 1 MB | SIMMs must match size/speed |
| 6 MB | 2 MB | 2 MB | 2 MB | (rare) |
| 8 MB | 2 MB | 3 MB* | 3 MB* | *3 MB = 1 MB + 2 MB parity boards |
| 10 MB | 2 MB | 4 MB | 4 MB | Official maximum |
- SIMM requirements:*
30-pin, 80 ns, 8-chip, non-parity (parity ignored). Logic board auto-detects via address-pin strapping; no jumpers.
Video Timing
| Parameter | Value |
|---|---|
| Pixel clock | 15.667 MHz (÷ 1) |
| Horizontal total | 704 px (512 active) |
| Vertical total | 370 lines (342 active) |
| Refresh rate | 60.15 Hz |
- Performance Snapshot (MacBench 1.0)
| Test | Score | vs SE/30 |
|---|---|---|
| CPU integer | 135 | 0.47× |
| Disk (80 MB) | 240 | 0.20× |
| Graphics | 110 | 0.45× |
| Overall | 128 | 0.50× |
> *Classic II halves the SE/30’s performance despite sharing a 68030, due to the 16-bit data path, slower DRAM, and “pseudo-DMA” SCSI.*
Notable Design Traits & Trivia
- Marketed as Performa 200 (consumer bundle) in some regions.
- Last all-in-one Macintosh to support 32-bit clean ROM but ships with 24-bit addressing forced; Mode32 enabler restores full 32-bit memory access.
- “Paris” logic-board codename; PCB bears Eiffel-Tower silkscreen.
- Developer jumper JP3 forces Debug-ROM shell on cold boot for board-level diagnostics.
- Hidden ROM tone: press ⌘ + ⌥ + ⌫ + Power to trigger a harmonic “strum” on cold start.