Macintosh Quadra 650
 | |
| Macintosh Quadra 650 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal Computer |
| Released | October 21, 1993 |
| Discontinued | September 12, 1994 |
| Intro price | US$2,780–$3,250 |
| CPU | Motorola 68040 @ 33 MHz |
| Memory | 4 or 8 MB RAM (expandable to 132 MB) |
| Storage | 230 or 500 MB SCSI HDD, optional 2X CD-ROM |
| Display | Up to 1152×870 (with VRAM expansion) |
| Sound | Monaural sound input; stereo output |
| Dimensions | 6.0" H × 13.0" W × 16.5" D (152 × 330 × 419 mm) |
| Weight | 25 lbs (11.3 kg) |
| OS / Firmware | System 7.1 – Mac OS 8.1 |
| Predecessor | Macintosh Centris 650 |
| Successor | Power 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 |
Related Models
- Macintosh Centris 650 – Predecessor with 25 MHz processor
- Macintosh Centris 610 – Smaller desktop variant (became Quadra 610)
- Macintosh Quadra 610 – Pizza-box form factor
- Macintosh IIvx – Uses same case design
- Power Macintosh 7100 – Successor, uses same case
Service Documentation
The official Apple Service Source documentation for this model:
See Also
- Macintosh Centris 650 General Maintenance
- Macintosh Centris 650 Troubleshooting
- Macintosh Centris 650 Capacitor Replacement Guide
Apple service data
Apple's own figures, from the Centris 650/Quadra 650 Service Source volume hosted on this wiki.[4]
| Item | Apple's figure |
|---|---|
| Processor | Motorola 68040 at 33 MHz (Centris 650: 25 MHz), built-in memory management unit |
| RAM | 4 or 8 MB, expandable to 132 MB (72-pin SIMM) |
| ROM / PRAM | 1 MB ROM; 256 bytes of non-volatile parameter memory |
| VRAM | 512K, expandable to 1 MB |
| Hard drive | Internal Apple SCSI, 80 MB to 500 MB; optional internal 5.25-inch CD-ROM |
| Sound | One stereo-capable output port; one monaural input port |
| Expansion | Three NuBus slots and one inline processor-direct slot |
| Ethernet | On-board Apple Ethernet port |
| SCSI | One DB-25 port, maximum six external devices (the computer is always device 7) |
| Electrical | 100–240 VAC, 50–60 Hz; 112 W maximum, not including display power |
| Case | Height 6.0 in. (152 mm), width 13.0 in. (330 mm), depth 16.5 in. (419 mm); 25 lb. (11.3 kg) |
| PRAM battery | Replace below 3.2 V. A lithium cell — neutralise leakage with sodium bicarbonate, never vinegar |
This volume has no Adjustments chapter — there is no rail-voltage procedure and no rail-tolerance table for this machine.[4]
References
- ↑ Macintosh Quadra 650 Specs, EveryMac.com—link(accessed 2026-02-10)
- ↑ Quadra 650, Low End Mac—link(accessed 2026-02-10)
- ↑ Macintosh Quadra 650 Specs, EveryMac.com—link(accessed 2026-02-10)
- ↑ 4.0 4.1 Apple Computer, Centris 650/Quadra 650, Service Source. Hosted here as Centris 650/Quadra 650 Service Source (File:Quadra.centris_650.pdf). Specifications, Adjustments and Additional Procedures — Battery Verification chapters.