Vintage Macs: Centris and Quadra

Centris 610

Macintosh Centris 610 "Going along with the auto-marketing trend toward meaningless names that sound important, Apple's new Centris line will serve as the company's mainstream, midlevel computers." MacUser, April 1993 (Apple names included Quadra, Performa, and Centris. The Centris name was dropped after just 9 months.)

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Overview

Creating a midpoint between the Mac II line and the Quadra series, the short-lived Centris models were introduced in February 1993. The Centris 610 introduced a new case style, one which would later be used for the Power Mac 6100. Unlike either the Mac II or Quadra lines, this model has a power switch on the front and cannot be turned on or off using the power key on the keyboard. (Many users more familiar with DOS hardware mistook the power switch for a floppy eject button - although it didn't take long to discover what the button really did.)

As a cost saving measure, the Centris 610 uses the less expensive 68LC040 CPU (no FPU), and the least expensive version of the 610 left out ethernet circuitry. Still, it averaged twice the performance of the IIci, Apple's workhorse business computer. An easy way to increase calculation speed on this model is to replace the CPU with a full-fledged 68040.

Unlike the IIci or Quadra 700, the Centris 610 has a drive bay for a CD-ROM drive. It also introduced a new, high-speed SCSI bus to the Macintosh line.

This model was upgraded to Quadra status in October.

Apple earns a Road Apple for the Centris name, which was discontinued after 9 months.

See our NuBus Video Card Guide for information on adding a NuBus video card, which will also require a NuBus adapter.

The Upgrade Box

Details

introduced 1993.02.10 at $2,520; replace by Quadra 610 1993.10.21
requires System 7.1 or later; highest version supported without a PPC upgrade is Mac OS 8.1.
CPU: 20 MHz 68LC040
FPU: none, 68LC040 can be replaced with 68040 CPU
performance: 9.7 est., relative to SE; 0.80, Speedometer 4
ROM: 1 MB
RAM: 4 MB on motherboard, expandable to 68 MB using 80ns 72-pin SIMMs; motherboard has 2 SIMM slots, which can be filled independently; can use 4 MB, 8 MB, 16 MB, and 32 MB SIMMs. If SIMMs are not the same speed, faster SIMM should be in bank 0 (frontmost slot).
video: 512 KB VRAM, expandable to 1 MB
- 512 x 384 @ 16-bit
- 640 x 480, 800 x 600, 832 x 624: 8-bit @ 512 KB, 16-bit @ 1 MB
- 832 x 624, 1024 x 768, 1152 x 870: 4-bit @ 512 KB, 8-bit @ 1 MB
L2 cache: optional, PDS
ADB ports: 2
DIN-8 serial ports: 2
SCSI: DB-25 connector on back of computer
hard drive: 80 or 230 MB
one PDS slot (NuBus adapter available)
size (HxWxD): 3.4" x 16.3" x 15.6"
weight: 14 lb.
PRAM battery: 3.6V half-AA
Gestalt ID: 52
addressing: 24-bit or 32-bit
upgrade path: Quadra 610, Power Mac PDS card, Power Mac 6100 (requires some case modification)

Accelerators & Upgrades

replace 68LC040 with 68040
MicroMac 128KB L2 cache
Chipping the QuadDoubler, a guide to clock chipping Sonnet QuadDoubler.
Output Enablers 28-28.6 MHz clock accelerator
MicroMac Speedy variable speed oscillator (to 26 MHz)
Sonnet QuadDoubler (40 MHz 68LC040 or 68040 )
Daystar Digital PowerPro 601, Apple Knowledge Base Archive. Runs at twice the speed of the original processor (40 MHz) and has a 1 MB level 2 cache (resource: Unofficial PowerPro 601 Page.
Power Mac 6100
Sonnet 100 MHz PowerPC 601 Presto PPC, discontinued

Accelerator Reviews

Sonnet Quad Doubler

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.
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.
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.
Upgraded Quadra a great server for vintage Mac networking, Carl Nygren, My Turn, 2008.05.21. The compact Quadra 610 runs quietly, and with a PowerPC upgrade, it rockets past regular 68040 Macs.
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?
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.
72-pin SIMM memory pricing, ramseeker
Mac Daniel: Is upgrading my Centris 650 worth it?
Centris 610, 650, 660av Differences, Apple Knowledge Base Archive
Vintage Macs, the email list for 68040-based Macs
Memory Upgrade Guide
Centris & Quadra 610, 650, and 800 Video Capabilities, Dale Adams, designer of video hardware on most Centris and Quadra models
MicroMac PM6100 Logic Board Upgrade, MicroMac, 1998.08.11. Everything you need to know about dropping in a Power Mac 6100 motherboard.
Printed reviews: Macworld, April 1993; Mac User, April 1993
Macintosh Centris 610 Technical Specifications, Apple Knowledge Base Archive

Cautions

Apple Computer considers this computer obsolete as of 2001.07.16 in the United States and 2001.07.23 in Canada. As of that date, service parts and documentation will no longer be available from Apple.
You must have a "fat" system installed to use a PowerPC upgrade.
Because the onboard ethernet port shares the same oscillator as the CPU, clock chipping the Centris 610 makes the internal ethernet port unusable. You can overcome this problem with a third party ethernet card.
If you have a non-Apple hard drive formatted with Silverlining, read this warning.
The fan filter for the 610 and other models that use the same case is inside the power supply. Sometimes a "bad" power supply can be repaired by clearing the dust out of the mesh screen near the fan.
This case has poor air circulation, which can cause replacement hard drives or accelerators to overheat. If this happens, the first thing to try is removing the small horizontal insert on the back. If this fails, look into replacing the fan in the power supply (contact Newark Electronics at 1-800-463-9275 for information on their 25cfm fan) or moving the hard drive to the CD-ROM bay (assuming you don't have a CD-ROM player).
Serial port normally restricted to 57.6 kbps; throughput with a 56k modem may be limited. See 56k modem page. For more information on Mac serial ports, read Macintosh Serial Throughput.

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