Macintosh Quadra 605
The Macintosh Quadra 605 is a personal computer introduced by Apple Computer on October 21, 1993.[1] It was the smallest and least expensive member of the Quadra line, housed in a compact "pizza box" case shared with the LC series.
 | |
| Macintosh Quadra 605 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 21, 1993 |
| Discontinued | October 17, 1994 |
| Intro price | US$900 (4 MB/80 MB), US$1,300 (8 MB/160 MB) |
| CPU | Motorola 68LC040 @ 25 MHz |
| Memory | 4 MB RAM soldered + 1 SIMM slot (up to 36 MB) |
| Storage | 80 MB or 160 MB SCSI hard drive, 1.44 MB floppy |
| Display | 512×384 to 1152×870 |
| Sound | 8-bit stereo |
| Dimensions | 2.9" H × 12.2" W × 15.3" D (7.4 × 31 × 38.9 cm) |
| Weight | 8.8 lbs (4 kg) |
| OS / Firmware | System 7.1 – Mac OS 8.1 |
| Model no. | M1476 |
The Quadra 605 targeted business users, while Apple sold essentially the same hardware to educational markets as the LC 475 and to consumers as the Performa 475 and Performa 476.[2] All three product lines share the same logic board design.
Model Variants
editThe Quadra 605 shares its logic board with several other Apple models:
- LC 475 – Education market variant
- Performa 475 – Consumer market variant
- Performa 476 – Consumer market variant (bundled with different software/peripherals)
The primary differences between these models are case color, bundled software, and distribution channel. The LC 475 case has a slightly different appearance, but the internal hardware is identical.
Architecture and Processor
editThe Quadra 605 uses a Motorola 68LC040 processor running at 25 MHz.[3] The "LC" designation indicates this is a cost-reduced version of the 68040 that lacks a floating-point unit (FPU). The processor is socketed and can be upgraded to a full 68040 with FPU, or to a PowerPC 601 via third-party upgrade cards.
The system bus runs at 25 MHz. The 68LC040 includes 8 KB of on-chip cache. An optional 256 KB L2 cache card could be installed on a riser card that plugged into the CPU socket.
ROM and System Software
editThe Quadra 605 contains a 1 MB ROM. It shipped with System 7.1 and officially supports up to Mac OS 8.1.
Memory and Storage
editRAM Configuration
editThe Quadra 605 has 4 MB of RAM soldered to the logic board. A single 72-pin SIMM slot allows expansion. Apple officially supports up to 32 MB SIMMs for a maximum of 36 MB total RAM. Third-party testing has demonstrated compatibility with 128 MB SIMMs, allowing up to 132 MB total.
RAM must be 80 ns or faster.
Storage Systems
editThe Quadra 605 shipped with either an 80 MB or 160 MB internal SCSI hard drive. A single 1.44 MB 3.5" manual-inject floppy drive is standard. External SCSI devices can be connected via the rear panel SCSI port.
Display and Graphics
editThe Quadra 605 has dedicated video with two VRAM SIMM slots. Standard configuration includes 512 KB of VRAM (two 256 KB SIMMs). Upgrading to 1 MB (two 512 KB SIMMs) increases color depth at higher resolutions.
| VRAM | Resolution | Color Depth |
|---|---|---|
| 512 KB | 512×384 | 16-bit (Thousands) |
| 512 KB | 640×480 | 8-bit (256 colors) |
| 512 KB | 832×624 | 8-bit (256 colors) |
| 512 KB | 1024×768 | 4-bit (16 colors) |
| 1 MB | 832×624 | 16-bit (Thousands) |
| 1 MB | 1024×768 | 8-bit (256 colors) |
| 1 MB | 1152×870 | 8-bit (256 colors) |
A second display can be supported by adding an LC III PDS video card.
Input/Output and Expansion
editPort Configuration
edit- 1× Apple Desktop Bus (ADB) for keyboard and mouse
- 2× Serial ports (printer and modem)
- 1× SCSI port (external)
- 1× Video port (DB-15)
- 1× Audio in (3.5mm)
- 1× Audio out (3.5mm)
Expansion
editThe Quadra 605 includes a single LC III PDS slot. However, in practice this slot is largely inaccessible due to the compact case design – installing PDS cards requires significant modification. The slot shares the same pinout as the LC III PDS.
Power Supply
editThe Quadra 605 uses the same compact power supply as the LC, LC II, LC III, and LC 475. The power supply accepts 100V-240V AC at 47-63 Hz and draws a maximum of 30 watts. This shared power supply design means capacitor replacement guides for the LC series apply to the Quadra 605.
General Maintenance
editFor detailed maintenance practices including cleaning, PRAM battery management, connector corrosion prevention, and voltage adjustments, refer to the dedicated Macintosh Quadra 605 General Maintenance page.
Capacitor Replacement Guide
editDetailed capacitor replacement guidelines for the logic board and power supply can be found on the Macintosh Quadra 605 Capacitor Replacement Guide page.
Troubleshooting
editA comprehensive troubleshooting guide addressing common issues including startup problems, video issues, and component failures is available on the Macintosh Quadra 605 Troubleshooting page.
Technical Details
editSystem Architecture at a Glance
edit| Sub-system | Specification |
|---|---|
| CPU | Motorola 68LC040 @ 25 MHz |
| FPU | None (LC variant) |
| Bus width | 32-bit data, 32-bit address |
| System Bus | 25 MHz |
| ROM | 1 MB |
| RAM | 4 MB soldered + 1 SIMM slot (max 36 MB official, 132 MB tested) |
| L1 Cache | 8 KB (on-chip) |
| L2 Cache | Optional 256 KB (riser card) |
| Video | 512 KB – 1 MB VRAM, up to 1152×870 |
| Sound | 8-bit stereo input/output |
| Storage | SCSI internal/external, 1.44 MB floppy |
| Expansion | 1× LC III PDS (limited accessibility) |
| Power | 30W max, 100-240V AC |
Gestalt ID and Model Numbers
edit| Identifier | Value |
|---|---|
| Apple Model No. | M1476 |
| Apple Order No. | M1821LL/A |
| Gestalt ID | 89 |
| PRAM Battery | 3.6V Lithium |
Service Documentation
editThe official Apple Service Source documentation for this model: