Macintosh LC III+
The Macintosh LC III+ is a personal computer released by Apple on October 18, 1993.[1] The LC III+ is essentially a faster version of the Macintosh LC III, with the processor clock speed increased from 25 MHz to 33 MHz.[2]
 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 18, 1993 |
| Discontinued | February 14, 1994 |
| Intro price | US$1,349 |
| CPU | Motorola 68030 @ 33 MHz |
| Memory | 4 MB RAM (expandable to 36 MB) |
| Storage | 80 MB or 160 MB SCSI HDD, 1.44 MB SuperDrive |
| Display | 640×480 8-bit (512K VRAM) or 16-bit (768K VRAM) |
| Sound | 8-bit stereo input/output |
| Dimensions | 2.9" H × 12.2" W × 15.3" D |
| Weight | 8.8 lbs (4.0 kg) |
| OS / Firmware | System 7.1 – System 7.6.1 |
| Predecessor | Macintosh LC III |
| Successor | Macintosh LC 475 |
| Codename | Elsie III+ |
| Model no. | M1254 |
Model Variants
The LC III+ was sold under several Performa brand names for consumer markets:
- Performa 460 — Base configuration
- Performa 466 — With different bundle
- Performa 467 — With CD-ROM drive
Design Changes
The LC III+ introduced a redesigned case with a smoother, more curved front bezel compared to the angular design of earlier LC models. This design continued in subsequent LC-series machines.
Architecture and Processor
The LC III+ uses a Motorola 68030 processor running at 33 MHz with a full 32-bit data bus. This provides approximately a 32% speed increase over the 25 MHz LC III.[3]
Like the LC III, the LC III+ includes a socket for an optional Motorola 68882 FPU.
The Gestalt ID for the Macintosh LC III+ is 62.
Memory and Storage
RAM Configuration
The LC III+ shipped with 4 MB of RAM standard, expandable to 36 MB using a single 72-pin SIMM slot.
| Configuration | SIMM Required |
|---|---|
| 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 |
Video RAM
The LC III+ includes 512 KB of VRAM onboard, expandable to 768 KB:
- 512 KB VRAM: 640×480 at 8-bit (256 colors)
- 768 KB VRAM: 640×480 at 16-bit (thousands of colors)
Storage Systems
Storage options included:
- 80 MB or 160 MB internal SCSI hard drive
- 1.44 MB SuperDrive
Input/Output and Expansion
Port Configuration
- 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)
- 2× Serial ports (Mini DIN-8)
- 1× Video output (DA-15)
Expansion
The LC III+ features a single LC Processor Direct Slot (LC PDS) and an FPU socket for the 68882 coprocessor.
General Maintenance
For detailed maintenance practices including cleaning, PRAM battery management, and connector care, refer to the dedicated Macintosh LC III+ General Maintenance page.
Troubleshooting
A comprehensive troubleshooting guide addressing common issues with the Macintosh LC III+ is available on the Macintosh LC III+ Troubleshooting page.
Capacitor Replacement
The Macintosh LC III+ logic board contains surface-mount electrolytic capacitors that commonly fail due to age. Detailed replacement guidelines can be found on the Macintosh LC III+ Capacitor Replacement Guide page.
Note: The LC III+ shares the same C22 reversed polarity silkscreen error as the LC III.
Technical Details
| Component | Specification |
|---|---|
| CPU | Motorola 68030 @ 33 MHz |
| FPU | Optional 68882 (socket provided) |
| PMMU | Integrated in 68030 |
| Data Bus | 32-bit |
| System Bus | 33 MHz |
| ROM | 1 MB |
| RAM | 4 MB (max 36 MB) |
| VRAM | 512 KB (max 768 KB) |