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Macintosh Quadra 650

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Macintosh Quadra 650
Quadra_650_Front.jpg
Macintosh Quadra 650
Specifications
ManufacturerApple Computer, Inc.
TypePersonal Computer
ReleasedOctober 21, 1993
DiscontinuedSeptember 12, 1994
Intro priceUS$2,780–$3,250
CPUMotorola 68040 @ 33 MHz
Memory8 MB RAM (expandable to 136 MB)
Storage230 or 500 MB SCSI HDD, optional 2X CD-ROM
DisplayUp to 1152×870 (with VRAM expansion)
Sound8-bit stereo sound
Dimensions6" H × 13" W × 16.5" D (15.2 × 33 × 41.9 cm)
Weight25 lbs (11.3 kg)
OS / FirmwareSystem 7.1 – Mac OS 8.1
PredecessorMacintosh Centris 650
SuccessorPower Macintosh 7100
Model no.M2118

The Macintosh Quadra 650 is a personal computer designed, manufactured, and sold by Apple Computer from October 1993 to September 1994.[1] It replaced the Macintosh Centris 650, featuring an upgraded 33 MHz 68040 processor with integrated FPU.[2]

Apple renamed the Centris line to Quadra in October 1993 to reduce product line confusion. The Quadra 650 uses the same logic board and IIvx tower case design as the Centris 650, with the processor upgraded from 25 MHz to 33 MHz.

Model Variants

The Quadra 650 was sold in several configurations:

  • M2107LL/A: 68040 @ 33 MHz, 8 MB RAM, 512 KB VRAM, 230 MB HDD (no CD-ROM)
  • M2016LL/A: 68040 @ 33 MHz, 8 MB RAM, 1 MB VRAM, 230 MB HDD, 2X CD-ROM
  • M2104LL/A: 68040 @ 33 MHz, 8 MB RAM, 1 MB VRAM, 500 MB HDD, 2X CD-ROM

All Quadra 650 models include the full 68040 with integrated FPU, unlike the entry-level Centris 650 which used the 68LC040.

Architecture and Processor

The Quadra 650 uses the Motorola 68040 processor running at 33 MHz. The clock input runs at 66 MHz, but the processor is not clock-doubled, operating at 33 MHz.[3] Third-party processor upgrades and PowerPC upgrade cards were available via the PDS slot.

Processor Specifications

Component Specification
CPU Motorola 68040 @ 33 MHz
Data Bus 32-bit
Address Bus 32-bit
L1 Cache 8 KB
FPU Integrated
System Bus 33 MHz
Addressing 24-bit or 32-bit

Upgrade Options

  • Sonnet Presto PPC 100 MHz PowerPC 601
  • Daystar PowerPro 601 (50 MHz with 1 MB L2 cache)
  • Various clock accelerators (up to 44 MHz)

Memory and Storage

RAM Configuration

The Quadra 650 has either 4 MB or 8 MB of RAM soldered to the logic board, with four 72-pin SIMM slots for expansion.

  • Minimum RAM: 4 or 8 MB (soldered)
  • Maximum RAM: 132 MB (4 MB onboard) or 136 MB (8 MB onboard)
  • SIMM Type: 72-pin, 80 ns or faster
  • Supported Sizes: 4 MB, 8 MB, 16 MB, 32 MB

RAM can be interleaved for improved performance by installing matching pairs of SIMMs.

Video RAM

Onboard video supports 512 KB or 1 MB of VRAM via two 80 ns VRAM SIMM slots.

Resolution 512 KB VRAM 1 MB VRAM
512×384 16-bit 16-bit
640×480 8-bit 16-bit
800×600 8-bit 16-bit
832×624 8-bit 16-bit
1024×768 4-bit 8-bit
1152×870 4-bit 8-bit

Additional displays can be supported via NuBus video cards.

Storage Systems

  • Internal Hard Drive: SCSI, 230 MB or 500 MB configurations
  • Floppy Drive: 1.44 MB SuperDrive (manual inject)
  • CD-ROM: Optional internal 2X AppleCD 300i (5.25" bay)

Input/Output and Expansion

Port Configuration

Port Quantity Notes
ADB 2 Keyboard and mouse
Serial (Mini DIN-8) 2 Modem and Printer, 57.6 kbps max
External SCSI (DB-25) 1 Up to 6 external devices
AAUI-15 Ethernet 1 Built-in
Video (DB-15) 1 VGA via adapter
Sound In 1 3.5mm stereo
Sound Out 1 3.5mm stereo

Expansion Slots

  • NuBus 90 Slots: 3
  • Processor Direct Slot (PDS): 1 (040 PDS)
  • 5.25" External Bay: 1 (available if CD-ROM not installed)

The floppy drive sled can also be used for a hard drive if the floppy is not needed.

General Maintenance

For detailed maintenance practices including cleaning, PRAM battery management, connector corrosion prevention, and voltage adjustments, refer to the dedicated Macintosh Centris 650 General Maintenance page.

Note: The Centris/Quadra 650 logic board uses tantalum capacitors rather than electrolytic capacitors, so the logic board does not require recapping. However, the power supply unit contains electrolytic capacitors that may need replacement.

PCB Schematics & Service Manual

The Macintosh Quadra 650 shares its logic board design with the Centris 650. The Apple Service Source manual covers both models.

Apple Service Manual

All Apple Service Manuals can be found on the Apple Service Source page.

Capacitor Replacement Guide

Detailed capacitor replacement guidelines can be found on the Macintosh Centris 650 Capacitor Replacement Guide page.

Important: The logic board uses tantalum capacitors and does not require recapping. Only the power supply contains electrolytic capacitors.

Retrobrite

To address plastic yellowing on the case, detailed instructions can be found on the Retrobrite page.

Troubleshooting

A comprehensive troubleshooting guide addressing no power, video issues, and common problems is available on the Macintosh Centris 650 Troubleshooting page.

Technical Details

System Architecture at a Glance

Sub-system Specification (Macintosh Quadra 650, October 1993)
CPU Motorola 68040 @ 33 MHz
Bus width 32-bit data • 32-bit address
ROM 1 MB
RAM 8 MB standard (expandable to 136 MB)
Video Up to 1152×870 with 1 MB VRAM
Sound 8-bit stereo, 22 kHz
Disks SCSI HDD, 1.44 MB floppy, optional CD-ROM
Expansion 3 NuBus 90, 1 PDS
Power 100–240V AC, 50–60 Hz, 230W max
Gestalt ID 36

Performance

Benchmark Score
Relative to SE 14.6
Speedometer 3 21.9
Speedometer 4 1.19
MIPS 29

See Also

References

  1. ↑ Macintosh Quadra 650 Specs, EveryMac.com—link(accessed 2026-02-10)
  2. ↑ Quadra 650, Low End Mac—link(accessed 2026-02-10)
  3. ↑ Macintosh Quadra 650 Specs, EveryMac.com—link(accessed 2026-02-10)
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