Editing Macintosh Centris 650

{{Infobox computer
| name         = Macintosh Centris 650
| image        = [[File:Quadra_650_Front.jpg]]
| caption      = Macintosh Centris 650
| manufacturer = Apple Computer, Inc.
| type         = Personal Computer
| release date = February 10, 1993
| discontinued = October 21, 1993 (renamed to Quadra 650)
| price        = US$2,699–$3,800
| cpu          = Motorola 68040 @ 25 MHz (or 68LC040)
| memory       = 4 or 8 MB RAM (expandable to 136 MB)
| storage      = 80–500 MB SCSI HDD, optional 2X CD-ROM
| display      = Up to 1152×870 (with VRAM expansion)
| sound        = 8-bit stereo sound
| dimensions   = 6" H × 13" W × 16.5" D (15.2 × 33 × 41.9 cm)
| weight       = 25 lbs (11.3 kg)
| os           = System 7.1 – Mac OS 8.1
| predecessor  = [[Macintosh IIci]]
| successor    = [[Power Macintosh 7100]]
| codename     = 
| model        = M1205
}}
The '''Macintosh Centris 650''' is a personal computer designed, manufactured, and sold by Apple Computer from February 1993 to October 1993.<ref>{{cite web |url=https://support.apple.com/kb/SP230 |title=Centris 650: Technical Specifications |publisher=Apple |access-date=2026-02-10}}</ref> It was introduced alongside the smaller [[Macintosh Centris 610]] as a replacement for the [[Macintosh IIci]] and [[Macintosh Quadra 700]].<ref>{{cite web |url=https://everymac.com/systems/apple/mac_centris/specs/mac_centris_650.html |title=Macintosh Centris 650 Specs |publisher=EveryMac.com |access-date=2026-02-10}}</ref>

In October 1993, Apple renamed the Centris 650 to the '''[[Macintosh Quadra 650]]''' and increased the processor speed to 33 MHz. The Centris and Quadra 650 share the same logic board and case design, which was originally introduced with the [[Macintosh IIvx]].<ref>{{cite web |url=https://en.wikipedia.org/wiki/Macintosh_Quadra_650 |title=Macintosh Quadra 650 |publisher=Wikipedia |access-date=2026-02-10}}</ref>

== Model Variants ==

The Centris 650 was sold in several configurations:

* '''Entry-level (M1207LL/A):''' 68LC040 @ 25 MHz (no FPU), 4 MB RAM, 512 KB VRAM, 80 MB HDD
* '''Mid-range (M1337LL/A):''' 68040 @ 25 MHz, 8 MB RAM, 512 KB VRAM, 230 MB HDD, Ethernet
* '''CD-ROM Bundle (M1279LL/A):''' 68040 @ 25 MHz, 8 MB RAM, 1 MB VRAM, 230 MB HDD, 2X CD-ROM, Ethernet

The later '''Quadra 650''' upgraded the processor to 33 MHz.

== Architecture and Processor ==

The Centris 650 uses the Motorola 68040 processor running at 25 MHz (33 MHz in the Quadra 650). The entry-level model shipped with a 68LC040, which lacks the integrated floating-point unit (FPU). Third-party processor upgrades were available.<ref>{{cite web |url=https://everymac.com/systems/apple/mac_centris/specs/mac_centris_650.html |title=Macintosh Centris 650 Specs |publisher=EveryMac.com |access-date=2026-02-10}}</ref>

=== Processor Specifications ===
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:70%; text-align:center;"
|-
! Component !! Specification
|-
| CPU || Motorola 68040 or 68LC040 @ 25 MHz (33 MHz Quadra)
|-
| Data Bus || 32-bit
|-
| Address Bus || 32-bit
|-
| L1 Cache || 8 KB
|-
| FPU || Integrated (68040 only)
|-
| System Bus || 25 MHz
|}

== Memory and Storage ==

=== RAM Configuration ===

The Centris 650 has either 4 MB or 8 MB of RAM soldered to the logic board. Four 72-pin SIMM slots accept 80 ns modules in 4 MB, 8 MB, 16 MB, or 32 MB sizes.

* '''Minimum RAM:''' 4 MB
* '''Maximum RAM:''' 132 MB (4 MB onboard) or 136 MB (8 MB onboard)
* '''SIMM Type:''' 72-pin, 80 ns or faster

RAM can be interleaved for improved performance.

=== Video RAM ===

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

* '''512 KB VRAM:''' 640×480 at 8-bit, 1152×870 at 4-bit
* '''1 MB VRAM:''' 640×480 at 16-bit, 1152×870 at 8-bit

The system cannot be expanded beyond 1 MB VRAM without a NuBus video card.

=== Storage Systems ===

* '''Internal Hard Drive:''' SCSI, 80 MB, 230 MB, or 500 MB configurations
* '''Floppy Drive:''' 1.44 MB SuperDrive (auto-inject)
* '''CD-ROM:''' Optional internal 2X AppleCD 300i (5.25" bay)

== Input/Output and Expansion ==

=== Port Configuration ===

{| class="wikitable" style="width:60%;"
|-
! Port !! Quantity !! Notes
|-
| ADB || 2 || Keyboard and mouse
|-
| Serial (Mini DIN-8) || 2 || Modem and Printer
|-
| External SCSI (DB-25) || 1 || Up to 6 external devices
|-
| AAUI-15 Ethernet || 1 || Some configurations only
|-
| Video (DB-15) || 1 || VGA via adapter
|-
| Sound In || 1 || 3.5mm
|-
| Sound Out || 1 || 3.5mm
|}

=== Expansion Slots ===

* '''NuBus Slots:''' 3
* '''Processor Direct Slot (PDS):''' 1 (68040 PDS)
* '''5.25" External Bay:''' 1 (available if CD-ROM not installed)

== 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 Centris 650 shares its logic board design with the Quadra 650.

=== Apple Service Manual ===

The Apple Service Source manual covers both the Centris 650 and Quadra 650.

All Apple Service Manuals can be found on the [[:Category:Apple Service Source|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 ==
<templatestyles src="Template:StyledTable/styles.css" />

=== System Architecture at a Glance ===
{| class="wikitable styled-table" style="width:90%; text-align:center;"
! Sub-system !! Specification
|-
| '''CPU''' || Motorola 68040/68LC040 @ 25 MHz (33 MHz Quadra)
|-
| '''Bus width''' || 32-bit data • 32-bit address
|-
| '''ROM''' || 1 MB
|-
| '''RAM''' || 4–8 MB onboard (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, 1 PDS
|-
| '''Power''' || 100–240V AC, 230W max
|-
| '''Gestalt ID''' || 30
|}

== Related Models ==

* '''[[Macintosh Quadra 650]]''' – Renamed version with 33 MHz processor
* '''[[Macintosh Centris 610]]''' – Smaller desktop variant
* '''[[Macintosh IIvx]]''' – Uses same case design
* '''[[Macintosh IIvi]]''' – Earlier model in same case

== Service Documentation ==

The official Apple Service Source documentation for this model:

<pdf width="800" height="500">File:Quadra.centris_650.pdf</pdf>

== See Also ==

* [[Macintosh Centris 650 General Maintenance]]
* [[Macintosh Centris 650 Troubleshooting]]
* [[Macintosh Centris 650 Capacitor Replacement Guide]]

== References ==
<references />

[[Category:Apple Vintage Computers]]
[[Category:Macintosh Centris]]