Editing Macintosh Quadra 660AV

{{Infobox computer
| name         = Macintosh Quadra 660AV
| image        = [[File:Macintosh_Centris_660AV.jpg|250px]]
| caption      = Macintosh Quadra 660AV (identical case to Centris 660AV)
| manufacturer = Apple Computer, Inc.
| type         = Personal Computer
| release date = October 21, 1993
| discontinued = September 12, 1994
| price        = US$1,970 – US$2,400
| cpu          = Motorola 68040 @ 25 MHz
| memory       = 8 MB RAM (expandable to 68 MB)
| storage      = 230 MB or 500 MB SCSI hard drive
| display      = Supports 512×384 to 1152×870
| sound        = 16-bit stereo input/output, PlainTalk microphone
| dimensions   = 3.4" H × 16.3" W × 15.6" D (8.6 cm × 41.4 cm × 39.6 cm)
| weight       = 14.0 lbs (6.4 kg)
| os           = System 7.1 – Mac OS 8.1
| predecessor  = [[Macintosh Centris 660AV]]
| successor    = [[Power Macintosh 6100|Power Macintosh 6100/60AV]]
| codename     = Tempest
| model        = M9040
}}
The '''Macintosh Quadra 660AV''' is a personal computer manufactured by Apple Computer from October 1993 to September 1994.<ref>{{cite web |url=https://support.apple.com/en-us/112216 |title=Macintosh Quadra 660AV: Technical Specifications |publisher=Apple Inc. |access-date=2026-02-10}}</ref> It is a rebadged version of the [[Macintosh Centris 660AV]], renamed when Apple discontinued the Centris product line in late 1993. The two machines are internally identical.<ref>{{cite web |url=https://everymac.com/systems/apple/mac_quadra/specs/mac_quadra_660av.html |title=Macintosh Quadra 660AV Specs |publisher=EveryMac.com |access-date=2026-02-10}}</ref>

The Quadra 660AV was one of Apple's first "AV" Macintoshes, featuring built-in video input/output capabilities and an AT&T 3210 digital signal processor for multimedia acceleration. It was introduced alongside the higher-end [[Macintosh Quadra 840AV]].

== AV Features ==

The "AV" designation indicates audiovisual capabilities beyond standard Macintosh models:

* '''AT&T 3210 DSP''' — A 55 MHz digital signal processor handles video compression, speech recognition, and audio processing, reducing CPU overhead for multimedia tasks<ref>{{cite web |url=https://lowendmac.com/1993/centris-660av-quadra-660av/ |title=Centris 660av (Quadra 660av) |publisher=Low End Mac |access-date=2026-02-10}}</ref>
* '''Video Input/Output''' — S-Video and composite RCA ports for capturing and outputting video signals
* '''GeoPort''' — High-speed serial port for telephony applications; an optional GeoPort Telecom Adapter enabled fax and modem functionality without dedicated hardware
* '''PlainTalk''' — Enhanced speech recognition and text-to-speech using the DSP

The 660AV was the first Macintosh to include GeoPort technology.

== Architecture and Processor ==

The Quadra 660AV uses a Motorola 68040 processor running at 25 MHz. Unlike the [[Macintosh Centris 610]] which used the 68LC040 (lacking an FPU), the 660AV includes a full 68040 with integrated floating-point unit.<ref>{{cite web |url=https://en.wikipedia.org/wiki/Macintosh_Quadra_660AV |title=Macintosh Quadra 660AV |publisher=Wikipedia |access-date=2026-02-10}}</ref>

The system includes SCSI Manager 4.3 with direct memory access (DMA), which improved disk performance significantly. In benchmarks, the 660AV outperformed the discontinued Quadra 700 (which shared the same 25 MHz 68040) and matched the Quadra 950 in some tests despite the 950's faster 33 MHz processor.

The Quadra AV machines introduced a new 2 MB "SuperMario" ROM that would later be used in all PowerPC-based Macintoshes.

== Memory and Storage ==

=== RAM Configuration ===

The Quadra 660AV includes 4 MB of RAM soldered to the logic board, with two 72-pin SIMM slots for expansion:

* '''Standard RAM:''' 8 MB (4 MB onboard + 4 MB SIMM)
* '''Maximum RAM:''' 68 MB (4 MB onboard + two 32 MB SIMMs)
* '''SIMM Speed:''' 70 ns or faster required
* '''SIMM Sizes:''' 4, 8, 16, or 32 MB modules (64 MB SIMMs not supported)

SIMMs can be installed individually; matched pairs are not required.

=== Storage Systems ===

* '''Hard Drive:''' 230 MB or 500 MB internal SCSI
* '''Floppy Drive:''' 1.44 MB 3.5" SuperDrive
* '''CD-ROM:''' Optional internal 2× caddy-loading drive

Early Centris 660AV units had auto-inject floppy drives similar to the Centris 610. Later Centris units and all Quadra 660AV models have manual-inject drives with a round indentation for fully inserting disks.

== Display and Graphics ==

The Quadra 660AV has 1 MB of VRAM soldered to the logic board (not expandable) supporting the following resolutions:

{| class="wikitable" style="width:70%"
|+ '''Supported Display Resolutions'''
|-
! Resolution !! Color Depth
|-
| 512 × 384 || 24-bit (16.7 million colors)
|-
| 640 × 400 || 24-bit (16.7 million colors)
|-
| 640 × 480 || 16-bit (thousands of colors)
|-
| 800 × 600 || 16-bit (thousands of colors)
|-
| 832 × 624 || 16-bit (thousands of colors)
|-
| 1024 × 768 || 8-bit (256 colors)
|-
| 1152 × 870 || 8-bit (256 colors)
|}

Video output is via a DB-15 connector. A second display can be added with a compatible NuBus or PDS video card.

The video output ports (S-Video and composite) can be used for recording to VCR or displaying on a television. Note that video mirroring is not supported—when outputting to TV/VCR, the computer monitor goes blank.

== Audio Capabilities ==

The Quadra 660AV features 16-bit stereo audio input and output:

* '''Sample Rates:''' Up to 44.1 kHz
* '''Input:''' PlainTalk microphone port (round mini-jack)
* '''Output:''' Stereo speaker port
* '''DSP Acceleration:''' The AT&T 3210 handles audio compression and decompression

== Input/Output and Expansion ==

=== Port Configuration ===

* '''ADB:''' 1 port (keyboard/mouse)
* '''Serial:''' 2 GeoPort-compatible DIN-8 RS-422 ports (printer and modem)
* '''SCSI:''' DB-25 external connector
* '''Video Out:''' DB-15 monitor connector
* '''Video I/O:''' S-Video in/out, composite RCA in/out
* '''Ethernet:''' AAUI-15
* '''Audio:''' PlainTalk microphone in, stereo speaker out

=== Expansion Slots ===

The Quadra 660AV has one expansion slot that accepts either:
* '''PDS Card''' — Processor Direct Slot card, or
* '''7" NuBus Card''' — Via optional adapter (Apple part M9049LL/A)

The NuBus adapter includes a DAV (digital audio/video) connector for video-related expansion cards.

If the optional CD-ROM drive is not installed, an external 5.25" bay is available.

== Power Supply ==

* '''Input Voltage:''' 100–240V AC (auto-switching)
* '''Frequency:''' 50–60 Hz
* '''Maximum Power:''' 86 watts
* '''PRAM Battery:''' 3.6V half-AA lithium

== Form Factor ==

The Quadra 660AV uses the same "pizza box" desktop enclosure as the [[Macintosh Centris 610]] and Centris 660AV. The only external difference between the Centris 660AV and Quadra 660AV is the nameplate.

== Software Compatibility ==

* '''Minimum:''' System 7.1 with System Enabler 088 v1.1
* '''Maximum:''' Mac OS 8.1
* '''With PowerPC Upgrade:''' Mac OS 9.1

'''Known Issues:'''
* The Startup Disk control panel in System 7.5–7.5.3 is incompatible with Quadra AV models; System 7.5.5 fixes this
* 24-bit addressing is not supported
* PowerPC upgrade cards require a "fat" (universal) system installation

== Upgrades ==

=== PowerPC Upgrade ===

Apple offered a Power Macintosh Upgrade Card that converted the Quadra 660AV to Power Macintosh 6100/60AV specifications for US$1,399. This allowed running PowerPC-native software while retaining 68040 compatibility.

=== Third-Party Accelerators ===

* '''Sonnet QuadDoubler''' — 50 MHz 68040 upgrade
* '''MicroMac Speedy''' — Variable speed oscillator (up to 29 MHz)
* '''MicroMac L2 Cache''' — 128 KB slot-free Level 2 cache

== General Maintenance ==

For detailed maintenance practices including cleaning, PRAM battery management, connector corrosion prevention, and voltage adjustments, refer to the dedicated [[Macintosh Centris 660AV General Maintenance]] page. The Quadra 660AV and Centris 660AV share identical hardware.

== Capacitor Replacement Guide ==

Detailed capacitor replacement guidelines for the logic board can be found on the [[Macintosh Centris 660AV Capacitor Replacement Guide]] page.

== Troubleshooting ==

A comprehensive troubleshooting guide addressing no power, no video, intermittent operation, and other common problems is available on the [[Macintosh Centris 660AV Troubleshooting]] page.

'''Tip:''' A dead or low-voltage PRAM battery can cause built-in video to fail. See [[Macintosh Centris 660AV Troubleshooting#PRAM Battery Issues|PRAM Battery Issues]] for details.

'''Tip:''' Hold Cmd-Opt-T-V during startup to force TV output mode.

== 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 (Macintosh Quadra 660AV, October 1993)
|-
| '''CPU''' || Motorola 68040 @ 25 MHz (full FPU)
|-
| '''DSP''' || AT&T 3210 @ 55 MHz
|-
| '''Bus Width''' || 32-bit data, 32-bit address
|-
| '''ROM''' || 2 MB ("SuperMario")
|-
| '''RAM''' || 8 MB standard (4 MB onboard + 4 MB SIMM), expandable to 68 MB
|-
| '''VRAM''' || 1 MB (not expandable)
|-
| '''Video''' || 512×384 to 1152×870, up to 24-bit color
|-
| '''Storage''' || 230/500 MB SCSI hard drive, 1.44 MB floppy, optional 2× CD-ROM
|-
| '''Networking''' || AAUI-15 Ethernet
|-
| '''Expansion''' || 1 PDS or 7" NuBus slot (with adapter)
|}

=== Processor Specifications ===

{| class="wikitable styled-table"
|-
! Component !! Specification
|-
| CPU || Motorola 68040 @ 25 MHz<ref>{{cite web |url=https://support.apple.com/en-us/112216 |title=Macintosh Quadra 660AV: Technical Specifications |publisher=Apple Inc. |access-date=2026-02-10}}</ref>
|-
| Clock Input || 50 MHz (internally divided)
|-
| Data Bus || 32-bit
|-
| Address Bus || 32-bit
|-
| L1 Cache || 8 KB (integrated)
|-
| FPU || Integrated (68040)
|-
| MMU || Integrated (68040)
|}

== Service Documentation ==

The official Apple Service Source documentation for this model:

<pdf width="800" height="500">File:Quadra.centris_660av.pdf</pdf>

== See Also ==

* [[Macintosh Centris 660AV]]
* [[Macintosh Quadra 840AV]]
* [[Power Macintosh 6100]]
* [[Macintosh Quadra 610]]

== References ==

<references />

== External Links ==

* [https://support.apple.com/en-us/112216 Macintosh Quadra 660AV Technical Specifications] — Apple Support
* [https://everymac.com/systems/apple/mac_quadra/specs/mac_quadra_660av.html Macintosh Quadra 660AV Specs] — EveryMac.com
* [https://lowendmac.com/1993/centris-660av-quadra-660av/ Centris 660av (Quadra 660av)] — Low End Mac

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