Vintage Macs: Centris and Quadra

Quadra 900

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Overview

October 1991 saw the introduction of Macs using Motorola's high-octane 68040 CPU. The Quadra 900 was a full-fledged tower design, although it had only a single front accessible drive bay. The Quadra 700 and 900 were the first Macs with built-in ethernet, using Apple's AAUI connector. The 900 was replaced by the 33 MHz 950 in May 1992.

Huge. It's one of the first adjectives that comes to mind, along with monstrous, massive, and just plain big. The 303W power supply alone is about the same size as a compact Mac. The Quadra 900 is build like a tank and obviously designed to sit on the floor. With 16 SIMM slots, you can add incredible amounts of memory, along with plenty of huge hard drives. This is obviously designed to be used as a server.

According to Apple, the monstrous power supply can support two 25-watt NuBus cards and three of the more typical 15-watt cards.

The internal SCSI bus is terminated on the motherboard, so internal SCSI devices should not be terminated. This is the opposite of all other Macs, except for the similar Quadra 950. However, the external SCSI bus works the same as on other Macs.

Although there are two separate SCSI buses, System 7.0-7.1 "folds" them together so the operating system sees a single virtual SCSI bus. Thus, under System 7.0-7.11 (and only under those systems) you must make sure that all devices on both chains have unique IDs.

See our NuBus Video Card Guide for information on adding a video card.

The Upgrade Box

Details

introduced 1991.10.21 at $7,200; replaced by Quadra 950 1992.05.18
requires System 7.0.1 or later; highest version supported without a PPC upgrade is Mac OS 8.1.
CPU: 25 MHz 68040
performance: 11.9, relative to SE; 1.33, Speedometer 4; 22 MIPS
ROM: 1 MB
RAM: 4 MB, expandable to 256 MB using 80ns 30-pin SIMMs; motherboard had 4 banks of 4 SIMM slots; can use 1 MB, 4 MB, 8 MB, and 16 MB SIMMs (8 MB and 16 MB SIMMs are not supported by Apple)
video: 1 MB VRAM, expandable to 2 MB; internal video does not support 16-bit mode
- 512 x 384: 24-bit
- 640 x 480, 832 x 624: 8-bit @ 1 MB, 24-bit @ 2 MB
- 1152 x 870: 8-bit
L2 cache: optional
ADB: 2 ports for keyboard and mouse
serial: 2 DIN-8 RS-422 ports on back of computer
SCSI: DB-25 connector on back of computer
hard drive: 160 or 400 MB
NuBus: 5 NuBus 90 slots
one PDS slot
size (HxWxD): 18.6" x 8.9" x 20.6"
weight: 36.8 lbs.
PRAM battery: 3.6V half-AA
Gestalt ID: 20
addressing: 32-bit
upgrade path: Quadra 950, Power Mac PDS card, Power Mac 9500

Accelerators & Upgrades

Chipping the Quadra
Chipping the QuadDoubler, a guide to clock chipping Sonnet QuadDoubler.
MicroMac PDS or slot-free 128 KB L2 cache
Output Enablers 33-35.7 MHz clock accelerator
MicroMac Speedy variable speed oscillator (to 30 MHz)
Sonnet QuadDoubler (50 MHz 68040)
Daystar Digital PowerPro 601, Apple Knowledge Base Archive. Runs at twice the speed of the original processor (50 MHz) and has a 1 MB level 2 cache (resource: Unofficial PowerPro 601 Page.
Workgroup Server 9150
Sonnet 100 MHz PowerPC 601 Presto PPC, discontinued

Online Resources

Low End Mac's best classic Mac OS deals. Best online prices for System 6, 7.1, 7.5.x, Mac OS 7.6, 8.0, 8.1, 8.5, 9.0, 9.2.2, and other versions.
Environmentally responsible retirement for old Macs, Rick Lawson, Pioneers in Mac Development, 2008.06.13. After you've scavenged what useful parts you can from your old Mac, what's the most environmentally friendly way to dispose of the rest?
Know your Mac's upgrade options, Phil Herlihy, The Usefulness Equation, 2008.08.26. Any Mac can be upgraded, but it's a question of what can be upgraded - RAM, hard drive, video, CPU - and how far it can be upgraded.
Apple will not abandon optical drives, the Mac drought, purposeful Mac acquisition, and more, Dan Knight, Low End Mac Mailbag, 2008.09.04. Also Mac OS X 10.5 on a G4-upgraded Blue & White G3 and problems using a flat panel display with a Quadra 700.
The compressed air keyboard repair, Charles Moore, Miscellaneous Ramblings, 2008.07.24. If your keyboard isn't working as well as it once did, blasting under the keys with compressed air may be the cure.
Tales of old Mac data retrieval, Adam Rosen, Adam's Apple, 2008.06.13. Getting apps and documents off 400K floppies, old disk images, and a Mac running System 5.
A vintage Mac network can be as useful as a modern one, Carl Nygren, My Turn, 2008.04.08. Old Macs can exchange data and share an Internet connection very nicely using Apple's old LocalTalk networking.
Vintage Mac networking and file exchange, Adam Rosen, Adam's Apple, 2007.12.19. How to network vintage Macs with modern Macs and tips on exchanging files using floppies, Zip disks, and other media.
Vintage Mac video and monitor mania, Adam Rosen, Adam's Apple, 2007.12.17. Vintage Macs and monitors didn't use VGA connectors. Tips on making modern monitors work with old Macs.
Getting inside vintage Macs and swapping out bad parts, Adam Rosen, Adam's Apple, 2007.12.14. When an old Mac dies, the best source of parts is usually another dead Mac with different failed parts.
Solving Mac startup problems, Adam Rosen, Adam's Apple, 2007.12.12. When your old Mac won't boot, the most likely culprits are a dead PRAM battery or a failed (or failing) hard drive.
Why you should partition your Mac's hard drive, Dan Knight, Mac Musings, 2008.12.11. "At the very least, it makes sense to have a second partition with a bootable version of the Mac OS, so if you have problems with your work partition, you can boot from the 'emergency' partition to run Disk Utility and other diagnostics."
Better and safer surfing with Internet Explorer and the Classic Mac OS, Max Wallgren, Mac Daniel, 2007.11.06. Tips on which browsers work best with different Mac OS versions plus extra software to clean cookies and caches, detect viruses, handle downloads, etc.
Hacking Mac OS 7.6.1 so many Mac OS 8 apps will run, Max Wallgren, Mac Daniel, 2007.10.30. With a little ResEdit work and a second copy of your System Folder, you can run a lot of OS 8 apps with Mac OS 7.6.1.
Simple Macs for simple tasks, Tommy Thomas, Welcome to Macintosh, 2007.10.19. Long live 680x0 Macs and the classic Mac OS. For simple tasks such as writing, they can provide a great, low distraction environment.
Interchangeabilty and compatibility of Apple 1.4 MB SuperDrive floppy drives, Sonic Purity, Mac Daniel, 2007.09.26. Apple used two kinds of high-density floppy drives on Macs, auto-inject and manual inject. Can they be swapped?
Apple's AAUI ethernet connector, Dan Knight, Online Tech Journal, 2007.09.04. From 1991 through 1995, Apple used a proprietary ethernet connection. Why they created AAUI and where to find adapters.
Connecting a LaserWriter to ethernet and the TiBook that wouldn't boot, Dan Knight, Low End Mac Mailbag, 2007.08.23. The importance of an AAUI ethernet adapter, the cost of PowerBook PRAM batteries, and booting old Macs from SCSI drives.
Apple's first phone a fake, build your own Macintel, Internet options for G3 Macs, and more, Dan Knight, Low End Mac Mailbag, 2007.07.23. Also a Cube that won't boot, moving data from an old Mac, useful resource for PowerBook 1400 owners, reformatting a Quadra's hard drive, finding an AirPort power supply, and more.
Mac System 7.5.5 can do anything Mac OS 7.6.1 can, Tyler Sable, Classic Restorations, 2007.06.04. Yes, it is possible to run Internet Explorer 5.1.7 and SoundJam with System 7.5.5. You just need to have all the updates - and make one modification for SoundJam.
Appearance Manager allows Internet Explorer 5.1.7 to work with Mac OS 7.6.1, Max Wallgren, Mac Daniel, 2007.05.23. Want a fairly modern browser with an old, fast operating system? Mac OS 7.6.1 plus the Appearance Manager and Internet Explorer may be just what you want.
Importance of G3 support in 10.5, clever USB/FireWire solution, upgrade options, and more, Dan Knight, Low End Mac Mailbag, 2007.05.01. Also the loss of the PowerBook brand, upgrading to an Intel iMac, Korg and the Mac, Quadra boot problems, and the value of a Mac Classic.
Format any drive for older Macs with patched Apple tools, Tyler Sable, Classic Restorations, 2007.04.25. Apple HD SC Setup and Drive Setup only work with Apple branded hard drives - until you apply the patches linked to this article.
Making floppies and CDs for older Macs using modern Macs, Windows, and Linux PCs, Tyler Sable, Classic Restorations, 2007.03.15. Older Macs use HFS floppies and CDs. Here are the free resources you'll need to write floppies or CDs for vintage Macs using your modern computer.
System 7 Today, advocates of Apple's 'orphan' Mac OS 7.6.1, Tommy Thomas, Welcome to Macintosh, 2006.10.26. Why Mac OS 7.6.1 is far better for 68040 and PowerPC Macs than System 7.5.x.
Mac OS 8 and 8.1: Maximum size, maximum convenience, Tyler Sable, Classic Restorations, 2006.09.11. Mac OS 8 and 8.1 add some useful new features and tools, and it can even be practical on 68030-based Macs.
Moving files from your new Mac to your vintage Mac, Paul Brierley, The 'Book Beat, 2006.06.13. Old Macs use floppies; new ones don't. Old Macs use AppleTalk; Tiger doesn't support it. New Macs can burn CDs, but old CD drives can't always read CD-R. So how do you move the files?
Setting up a 68040-based Mac media center, Nathan Thompson, Embracing Obsolescence, 2006.05.12. Yes, that old '040-based Quadra or Performa just might make a decent media center for listening to MP3s and watching videos.
System 7.6.1 is perfect for many older Macs, John Martorana, That Old Mac Magic, 2006.03.24. Want the best speed from your old Mac? System 7.6.1 can give you that with a fairly small memory footprint - also helpful on older Macs.
System 7.5 and Mac OS 7.6: The beginning and end of an era, Tyler Sable, Classic Restorations, 2006.02.15. System 7.5 and Mac OS 7.6 introduced many new features and greater modernity while staying within reach of most early Macintosh models.
Web browser tips for the classic Mac OS, Nathan Thompson, Embracing Obsolescence, 2006.01.03. Tips on getting the most out of WaMCom, Mozilla, Internet Explorer, iCab, Opera, and WannaBe using the classic Mac OS.
PowerPC Upgrades for 040 PDS: Apple Power Mac Upgrade Card, DayStar PowerPro 601, Sonnet Presto PPC 700
Options For '040s, Adam Robert Guha, Apple Archive, 2000.06.05. Advice about operating systems, upgrades, what Quadra to choose, and more.
Games for '040s, Low End Mac Gaming, Brian Rumsey, 2000.02.25. This week Brian looks at games to play on 68040-based Macs.
Gaming on '040s, Brian Rumsey, Low End Mac Gaming, 2000.02.16. Those old 68040-class Macs still have game.
6100 DOS Cards, Quadras, and You. How to use a Power Mac 6100 DOS card with 66 MHz 486DX2 CPU in a Quadra
Easter Egg, MacKiDo
Vintage Macs, the email list for 68040-based Macs
Memory Upgrade Guide
Quadra 700 & 900 On-board Video Capabilities, Dale Adams, designer of video hardware on most Centris and Quadra models
For more information on Mac serial ports, read Macintosh Serial Throughput
Macintosh Quadra 900 Technical Specifications, Apple Knowledge Base Archive

Cautions

Outside of California, Apple discontinued support and parts orders for this model on 2001.01.01. You may be able to find dealers with parts inventory either locally or on our parts and service list.
In 24-bit video mode, the Quadra 700 and 900 actually use 32-bits per pixel. While most Macs can display 24-bit video at 640 x 480 with 1 MB of VRAM, you must have 2 MB VRAM for 24-bit on these models (see Apple Knowledge Base Archive #10992 for more details).
You must have a "fat" system installed to use a PowerPC upgrade as well as the 68040 CPU.

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