Macintosh LC 475
 | |
| Macintosh LC 475 / Quadra 605 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 21, 1993 |
| Discontinued | May 1, 1994 |
| Intro price | US$1,085 |
| CPU | Motorola 68LC040 @ 25 MHz |
| Memory | 4–8 MB RAM (expandable to 36 MB official, 132 MB actual) |
| Storage | 80 MB, 160 MB, or 250 MB SCSI HDD, 1.44 MB SuperDrive |
| Display | 640×480 8-bit (512K VRAM) or 16-bit (1 MB VRAM) |
| Sound | 8-bit stereo input/stereo output |
| Dimensions | 2.9" H × 12.2" W × 15.3" D |
| Weight | 8.8 lbs (4.0 kg) |
| OS / Firmware | System 7.1 – Mac OS 8.1 |
| Predecessor | Macintosh LC III+ |
| Successor | Macintosh LC 580 |
| Codename | Aladdin |
| Model no. | M1476 |
The Macintosh LC 475 is a personal computer released by Apple on October 21, 1993.[1] The LC 475 represented a major upgrade to the LC line, featuring a Motorola 68LC040 processor—the same architecture used in the Quadra line—making it the fastest LC model at launch.[2]
The LC 475 shares its logic board with the Quadra 605 and Performa 475/476, differing only in bundled software and marketing.
Model Variants
[edit | edit source]The LC 475 was sold under several Performa brand names:
- Performa 475 — Consumer variant
- Performa 476 — Consumer variant with different bundle
The Quadra 605 uses the identical logic board and hardware.
Architecture and Processor
[edit | edit source]The LC 475 uses a Motorola 68LC040 processor running at 25 MHz. The "LC" designation indicates this is a cost-reduced 68040 without a built-in FPU. However, the processor is socketed, allowing replacement with a full 68040 for FPU support.[3]
The 68LC040 includes:
- 8 KB L1 cache (4 KB instruction + 4 KB data)
- Integrated MMU
- Full 32-bit data and address buses
The Gestalt ID for the Macintosh LC 475 is 89.
PowerPC Upgrade: The LC 475 can accept a PowerPC 601 upgrade card, enabling use of Mac OS 8.1 and PowerPC-native software.
Memory and Storage
[edit | edit source]RAM Configuration
[edit | edit source]The LC 475 shipped with 4–8 MB of RAM standard, officially expandable to 36 MB. In practice, the system can address up to 132 MB using a 128 MB 72-pin SIMM plus onboard RAM.
| Configuration | Method |
|---|---|
| 4 MB | 4 MB onboard |
| 8 MB | 4 MB onboard + 4 MB SIMM |
| 12 MB | 4 MB onboard + 8 MB SIMM |
| 20 MB | 4 MB onboard + 16 MB SIMM |
| 36 MB | 4 MB onboard + 32 MB SIMM (official max) |
| 132 MB | 4 MB onboard + 128 MB SIMM (actual max) |
Video RAM
[edit | edit source]The LC 475 includes 512 KB of VRAM (2×256 KB SIMMs), expandable to 1 MB (2×512 KB SIMMs):
- 512 KB VRAM: 640×480 at 8-bit (256 colors)
- 1 MB VRAM: 640×480 at 16-bit (thousands of colors)
This was the first LC to support stereo audio output.
Storage Systems
[edit | edit source]Storage options included:
- 80 MB, 160 MB, or 250 MB internal SCSI hard drive
- 1.44 MB SuperDrive (manual-inject mechanism)
Input/Output and Expansion
[edit | edit source]Port Configuration
[edit | edit source]- 1× Apple Desktop Bus (ADB) port
- 1× External SCSI (DB-25)
- 1× Audio input (3.5mm stereo minijack)
- 1× Audio output (3.5mm stereo minijack) — Stereo output
- 2× Serial ports (Mini DIN-8)
- 1× Video output (DA-15)
Expansion
[edit | edit source]The LC 475 features a single LC Processor Direct Slot (LC PDS). It does not have a separate FPU socket since the 68040 integrates FPU functionality (when using a full 68040 instead of the 68LC040).
Power Supply
[edit | edit source]The LC 475 uses a 30W power supply.
General Maintenance
[edit | edit source]For detailed maintenance practices including cleaning, PRAM battery management, and connector care, refer to the dedicated Macintosh LC 475 General Maintenance page.
Troubleshooting
[edit | edit source]A comprehensive troubleshooting guide addressing common issues with the Macintosh LC 475 is available on the Macintosh LC 475 Troubleshooting page.
Capacitor Replacement
[edit | edit source]The Macintosh LC 475 logic board contains fewer capacitors than earlier LC models and is generally easier to recap. Detailed replacement guidelines can be found on the Macintosh LC 475 Capacitor Replacement Guide page.
Technical Details
[edit | edit source]| Component | Specification |
|---|---|
| CPU | Motorola 68LC040 @ 25 MHz |
| FPU | None (socketed, upgradeable to full 68040) |
| L1 Cache | 8 KB (4 KB data + 4 KB instruction) |
| MMU | Integrated in 68040 |
| Data Bus | 32-bit |
| System Bus | 25 MHz |
| ROM | 1 MB |
| RAM | 4–8 MB (max 132 MB) |
| VRAM | 512 KB (max 1 MB) |
| PSU | 30W |