Macintosh Quadra 900
 | |
| Macintosh Quadra 900 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 21, 1991 |
| Discontinued | May 18, 1992 |
| Intro price | US$7,200 |
| CPU | Motorola 68040 @ 25 MHz |
| Memory | 4 MB RAM (expandable to 256 MB) |
| Storage | 160 MB or 400 MB SCSI hard drive, 1.44 MB floppy |
| Display | DB-15 video output, 1 MB VRAM (expandable to 2 MB) |
| Sound | 8-bit stereo output, mono input |
| Dimensions | 18.6" H × 8.9" W × 20.6" D (47.2 × 22.6 × 52.3 cm) |
| Weight | 36.8 lbs (16.7 kg) |
| OS / Firmware | System 7.0.1 – Mac OS 8.1 |
| Predecessor | Macintosh IIfx |
| Successor | Macintosh Quadra 950 |
| Model no. | M4200 |
The Macintosh Quadra 900 is a personal computer designed and manufactured by Apple Computer, released on October 21, 1991.[1] It was introduced alongside the Quadra 700 as the first computers in the Quadra family using the Motorola 68040 processor.[2]
The Quadra 900 was Apple's first Macintosh in a tower case form factor, designed for use as a departmental server or high-end workstation. It was discontinued after approximately six months in favor of the Quadra 950, which features a 33 MHz processor and improved graphics support.
Architecture and Processor
[edit | edit source]The Quadra 900 uses a Motorola 68040 processor running at 25 MHz with an integrated FPU and 8 KB of Level 1 cache. The 68040 is a full 32-bit processor with 32-bit data and address buses.
The system bus runs at 25 MHz. The clock input runs at 50 MHz, but the processor itself operates at 25 MHz (not clock-doubled).
Memory and Storage
[edit | edit source]RAM Configuration
[edit | edit source]The Quadra 900 has 16 30-pin SIMM slots supporting 80 ns RAM modules. RAM must be installed in groups of four identical SIMMs. Apple officially supported 64 MB, but third-party configurations achieved 256 MB using sixteen 16 MB SIMMs.[3]
Standard configuration shipped with 4 MB of RAM.
ROM and System Software
[edit | edit source]The Quadra 900 includes a 1 MB ROM. It shipped with System 7.0.1 and supports Mac OS versions up to 8.1. It is the earliest Macintosh model capable of running Mac OS 8.
Storage Systems
[edit | edit source]The system uses a SCSI interface for storage. Factory configurations included either no hard drive, a 160 MB, or a 400 MB SCSI hard drive. A 1.44 MB SuperDrive floppy drive is standard.
A front-facing 5.25" drive bay is available for a CD-ROM drive, tape backup, or SyQuest drive. Two additional internal 5.25" bays are available (three if no hard drive is installed).
Display and Graphics
[edit | edit source]The Quadra 900 includes integrated video with a DB-15 connector. Standard VRAM is 1 MB, expandable to 2 MB via four 256K VRAM SIMM slots (80 ns).
Display resolutions supported:
- 512×384 at 24-bit color (1 MB VRAM)
- 640×480, 832×624, 1152×870 at 8-bit color (1 MB VRAM)
- Up to 832×624 at 24-bit color (2 MB VRAM)
- 1152×870 at 8-bit color (2 MB VRAM)
Additional displays can be supported via NuBus video cards.
Audio Capabilities
[edit | edit source]The Quadra 900 features:
- 3.5mm stereo output jack
- 3.5mm mono input jack
- 8-bit audio
Input/Output and Expansion
[edit | edit source]Port Configuration
[edit | edit source]- 1× Apple Desktop Bus (ADB) port
- 2× Serial ports (printer and modem)
- 1× DB-25 SCSI port
- 1× AAUI-15 Ethernet port (built-in)
- 1× DB-15 video output
- 3.5mm audio input and output jacks
Expansion Slots
[edit | edit source]The Quadra 900 provides extensive expansion options:
- 5× NuBus slots (three provide 15W, two provide 25W power)
- 1× 68040 Processor Direct Slot (PDS)
Upgrade Options
[edit | edit source]Apple offered a Quadra 950 logic board upgrade for $1,899 and a Workgroup Server 95 upgrade for $2,499. With the Power Macintosh Upgrade Card installed, the system runs at 50 MHz and identifies as "Power Macintosh 900" in System Profiler.
Design and Features
[edit | edit source]The Quadra 900 uses a mid-tower case measuring 18.6 inches (47 cm) tall. The case design was shared with the Quadra 950 and Workgroup Server 95.
A three-position key-lock on the front panel provides security options:
- Off – Machine cannot be powered up
- On – Normal operation
- Secure – Floppy drive and ADB port are disabled
Power supply provides up to 303W and accepts 100-240V AC at 50-60 Hz.
General Maintenance
[edit | edit source]For detailed maintenance practices including cleaning, PRAM battery management, connector corrosion prevention, and voltage adjustments, refer to the dedicated Macintosh Quadra 900 General Maintenance page.
Capacitor Replacement Guide
[edit | edit source]Detailed capacitor replacement guidelines can be found on the Macintosh Quadra 900 Capacitor Replacement Guide page.
Troubleshooting
[edit | edit source]A comprehensive troubleshooting guide addressing power issues, video problems, and error codes is available on the Macintosh Quadra 900 Troubleshooting page.
Technical Details
[edit | edit source]System Architecture at a Glance
[edit | edit source]| Sub-system | Specification (Macintosh Quadra 900, 1991) |
|---|---|
| CPU | Motorola 68040 @ 25 MHz |
| FPU | Integrated |
| L1 Cache | 8 KB |
| Bus width | 32-bit data • 32-bit address |
| Bus speed | 25 MHz |
| ROM | 1 MB |
| RAM | 4 MB standard, 256 MB maximum (16× 30-pin SIMM slots) |
| Video | 1-2 MB VRAM, up to 1152×870 |
| Sound | 8-bit stereo output, mono input |
| Storage | SCSI hard drive, 1.44 MB floppy |
| Expansion | 5× NuBus, 1× PDS |
| Ports | ADB, 2× Serial, SCSI, AAUI-15 Ethernet, DB-15 video |
Service Documentation
[edit | edit source]The official Apple Service Source documentation for this model:
See Also
[edit | edit source]- Macintosh Quadra 700 – Desktop Quadra released the same day
- Macintosh Quadra 950 – Direct successor with 33 MHz processor
- Macintosh IIfx – Predecessor high-end Macintosh