Macintosh Quadra 900
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| Macintosh Quadra 900 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal computer |
| Released | October 21, 1991 |
| Discontinued | May 18, 1992 |
| Intro price | US$7,200 (no hard drive) |
| CPU | Motorola 68040 at 25 MHz |
| Memory | 4 MB, expandable to 256 MB (sixteen 30-pin SIMM slots, 80 ns) |
| Storage | 160 or 400 MB SCSI hard drive (optional); 1.4 MB SuperDrive |
| Display | Built-in video, 1 MB VRAM (expandable to 2 MB), DB-15 |
| Sound | 8-bit stereo output, 8-bit mono input |
| Dimensions | 18.6 × 8.9 × 20.6 in (473 × 224 × 523 mm) |
| Weight | 36 lb 12 oz (16.7 kg) without hard drive |
| OS / Firmware | System 7.0.1 to Mac OS 8.1 |
| Predecessor | Macintosh IIfx |
| Successor | Macintosh Quadra 950 |
| Model no. | M4200 |
The Macintosh Quadra 900 is a tower personal computer that Apple Computer introduced on 21 October 1991, alongside the Macintosh Quadra 700, and replaced with the Macintosh Quadra 950 on 18 May 1992. It uses a 25 MHz Motorola 68040.[1][2] EveryMac describes it as the first Macintosh in a full tower case.[3] The Quadra 700 and 900 were the first Macintosh models with built-in Ethernet, through Apple's AAUI connector.[1]
Apple services the Quadra 900, the Quadra 950 and the Apple Workgroup Server 95 in one manual. The Quadra 900 has a 25 MHz logic board and the 950 and AWS 95 a 33 MHz board, and Apple's take-apart procedure warns that the correct board must be fitted.[2]
Specifications
[edit | edit source]| Item | Apple's figure |
|---|---|
| Processor | Motorola 68040, 25 MHz, with PMMU, FPU and 8K cache; 32-bit address and data bus |
| RAM | 4 MB standard, expandable to 256 MB (80 ns or faster SIMMs) |
| ROM and PRAM | 1 MB in two 150 ns 256K × 16-bit chips; 256 bytes of parameter memory |
| VRAM | 1 MB, expandable to 2 MB (100 ns or faster VRAM SIMMs) with four 256K or two 512K SIMMs |
| Video | Built-in 8-bit video, upgradeable to 24-bit; Apple monitors, VGA, NTSC and PAL |
| Clock/calendar | ASIC clock chip with PRAM and DFAC support, seven-year lithium battery |
| Floppy drive | Internal 1.4 MB Apple SuperDrive |
| SCSI | One external DB-25 port and one internal 50-pin port; up to eight devices including the computer (always ID 7) |
| NuBus | Five slots for standard and oversize cards; burst-mode transfers and NuBus '90; 96-pin connectors |
| Processor-direct slot | One 68040 PDS, 140-pin connector |
| Serial | Two RS-232/RS-422 ports, mini DIN-8, 230.4 Kbit/s maximum |
| ADB | One port |
| Sound | 8-bit stereo output, 8-bit mono input; electret microphone; four-voice wavetable synthesis |
| Ethernet | One port (the Service Source calls it an AUI-15 connector) |
| Electrical | 100-240 V AC RMS, self-configuring; 50-60 Hz single phase; 303 W maximum, not including the monitor |
| Weight | 36 lb 12 oz (16.7 kg) without a hard drive |
| Environment | 10-40 °C operating; 20-80 % relative humidity, non-condensing |
The Service Source gives the height as "16.8 in. (473 mm)". 473 mm is 18.6 in, the height EveryMac and Low End Mac give, so the inch figure is a transposition.[2][3]
Hardware
[edit | edit source]Memory and video
[edit | edit source]The sixteen 30-pin SIMM slots take 1 MB or 4 MB SIMMs in groups of four; Apple notes that 8 MB and 16 MB SIMMs can be used but are not supported by Apple.[4]
| Resolution | 1 MB VRAM | 2 MB VRAM |
|---|---|---|
| 512 × 384 | 24-bit | 24-bit |
| 640 × 480 | 8-bit | 24-bit |
| 832 × 624 | 8-bit | 24-bit |
| 1152 × 870 | 8-bit | 8-bit |
The built-in video has no 16-bit mode, and in 24-bit mode it stores 32 bits per pixel, which is why 24-bit colour at 640 × 480 needs 2 MB of VRAM.[1] Apple notes that 512K VRAM SIMMs can be fitted but only 256K of each is used.[4]
SCSI
[edit | edit source]The Quadra 900 has separate internal and external SCSI buses. Apple's Developer Note for the Centris 610, Centris 650 and Quadra 800 describes the 900 and 950 as using two SCSI driver ICs, with both segments terminated on the logic board and built-in terminators for the last device on the long internal cable.[5] Internal drives should therefore not carry their own terminators: Apple's chart for devices that work internally or externally but not both includes making sure the internal hard drives are not terminated.[2][1] Under System 7.0 and 7.1 the two buses are treated as one, so every device on both needs a unique ID.[1]
Power, keyswitch and cooling
[edit | edit source]Apple rates the supply at 303 W, not including the monitor, on a self-configuring 100-240 V AC input.[2] According to Apple, as reported by Low End Mac, it can support two 25 W NuBus cards and three 15 W cards.[1] The fan is mounted on the power supply and comes out with it.[2]
A keyswitch on the front panel has a secure position. Apple's symptom charts start several entries (floppy drive not working or not ejecting, cursor not moving, keyboard not responding) by checking that the keyswitch is not set to secure.[2] Blocked vents on the side and rear can make the thermal protection circuit shut the system down; it should work again after 30 to 40 minutes.[2]
Model configurations
[edit | edit source]EveryMac lists configurations with no hard drive, a 160 MB or a 400 MB hard drive, at US$7,200 and US$8,500; the order number of the base configuration is M4210LL/A.[3]
Upgrades
[edit | edit source]Apple offered a Quadra 950 logic board upgrade (after which About This Macintosh still reports a Quadra 900 until the system software is reinstalled), a Workgroup Server 95 upgrade (a PDS card with A/UX 3.0.1 and Retrospect), a DDS-DC tape drive upgrade, the Power Macintosh Upgrade Card for the PDS, and a Workgroup Server 9150 logic board upgrade.[2]
Maintenance and repair
[edit | edit source]The logic board is built with tantalum capacitors, according to Recap-a-Mac, so the leaking surface-mount electrolytics of later Macintosh boards are not a concern on it.[6] The PRAM battery is a 3.6 V lithium cell; Apple's threshold for replacing it is 3.2 V.[4][2] See Macintosh Quadra 900 General Maintenance, Macintosh Quadra 900 Troubleshooting and Macintosh Quadra 900 Capacitor Replacement Guide.
Documentation
[edit | edit source]- Macintosh Quadra 900/950/ AWS 95 Service Source: Apple's service manual for the Quadra 900, 950 and Workgroup Server 95.
Gallery
[edit | edit source]-
Quadra 700 and Quadra 900
Related pages
[edit | edit source]- Macintosh Quadra 900 General Maintenance
- Macintosh Quadra 900 Troubleshooting
- Macintosh Quadra 900 Capacitor Replacement Guide
- Macintosh Quadra 700
- Macintosh Quadra 950
- Macintosh IIfx
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Adam Geller, "Quadra 900", Low End Mac (retrieved 2026-09-30). Introduced 21 October 1991 at US$7,200, replaced by the Quadra 950 on 18 May 1992; System 7.0.1 to Mac OS 8.1; first Macs with built-in Ethernet (with the Quadra 700) using Apple's AAUI connector; NuBus power (two 25 W and three 15 W cards, according to Apple); internal SCSI terminated on the logic board; 32 bits per pixel in 24-bit mode; upgrade paths.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Apple Computer, Macintosh Quadra 900/950/AWS 95 Service Source. Hosted here as Macintosh Quadra 900/950/ AWS 95 Service Source (File:Quadra_900.950.ws_95.pdf). Specifications (PDF pp. 5-16), Symptom Charts (pp. 19-34), Take Apart (pp. 36-63), Upgrades (pp. 65-109), Additional Procedures (pp. 111-115), Exploded View (p. 117).
- ↑ 3.0 3.1 3.2 EveryMac.com, "Macintosh Quadra 900 Specs" (retrieved 2026-09-30). Dates, prices US$7,200 and US$8,500, standard configurations (no hard drive, 160 MB or 400 MB), model M4200, 18.6 × 8.9 × 20.6 in.
- ↑ 4.0 4.1 4.2 4.3 Apple, "Macintosh Quadra 900: Technical Specifications" (retrieved 2026-09-30). RAM slots, SIMM sizes and grouping; video resolution table; 303 W, 10 A; 3.6 V lithium battery.
- ↑ Apple Computer, Macintosh Centris 610, Macintosh Centris 650, and Macintosh Quadra 800 Developer Note, "Comparison With Other Macintosh Computers", p. 20. Hosted here as Macintosh Centris 610 Centris 650 and Quadra 800 Developer Note.
- ↑ Recap-a-Mac, "Recapping Service", FAQ "Why do you use tantalum capacitors as replacements?" (retrieved 2026-09-30): "Apple actually used tantalum capacitors instead of surface mount electrolytics for some of their vintage Macs (such as the Quadra 700 and Quadra 900)".