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{{Infobox computer
{{Infobox computer
| name        = Macintosh Classic
| name        = Macintosh Classic
| image        = [[File:Macintosh classic.jpg|250px]]
| image        = [[File:Macintosh classic.jpg|260px|frameless]]
| caption      = Macintosh Classic
| caption      = Macintosh Classic with ADB keyboard and mouse (Wikimedia Commons, CC BY-SA 3.0)
| manufacturer = Apple Computer, Inc.
| manufacturer = Apple Computer, Inc.
| type        = Personal Computer
| type        = Personal computer
| release date = October 15, 1990
| release_date = 15 October 1990
| discontinued = September 14, 1992
| discontinued = 14 September 1992
| price        = US$999 – $1,499
| price        = US$999 (floppy only); US$1,499 (40 MB hard disk, 2 MB RAM)
| cpu          = Motorola 68000 @ 8 MHz
| cpu          = Motorola 68000 @ 7.8336 MHz
| memory      = 1 MB RAM (expandable to 4 MB)
| memory      = 1 MB on the logic board; 4 MB maximum with Apple's memory expansion board
| storage      = 1.44 MB 3.5" floppy drive, optional 40 MB SCSI hard drive
| rom          = 512 KB
| display      = 9" monochrome CRT (512×342 pixels)
| storage      = Internal 1.4 MB floppy drive; optional internal 40 MB SCSI hard disk
| sound        = Monaural 8-bit, 22 kHz
| display      = 9-inch monochrome CRT, 512 × 342 pixels
| dimensions  = 13.2" H × 9.6" W × 10.9" D
| sound        = Four-voice, 8-bit D/A conversion, 22 kHz sampling
| weight      = 16.5 lbs (7.5 kg)
| ports        = 1 × ADB (mini DIN-4); DB-19 external floppy; DB-25 SCSI; 2 × RS-422 serial (mini DIN-8); headphone
| power        = 100–120 V AC, 47–63 Hz, 100 W maximum (220 V power/sweep boards also exist)
| dimensions  = 13.2 in H × 9.7 in W × 11.2 in D (33.6 × 24.6 × 28.5 cm)
| weight      = 7.3–7.8 kg (16–17.1 lb) without a hard disk
| os          = System 6.0.7 – System 7.5.5
| os          = System 6.0.7 – System 7.5.5
| predecessor  = [[Macintosh SE]]
| predecessor  = [[Macintosh SE]]
| successor    = [[Macintosh Classic II]]
| successor    = [[Macintosh Classic II]]
| codename    = Elsie, Skywriter
| codename    = XO, Civic
| model        = M0420
| model        = M0420
}}
}}
The '''Macintosh Classic''' was introduced by Apple on October 15, 1990, as a low-cost alternative in the Macintosh lineup and a spiritual successor to the original Macintosh 128K and SE. It retained the same 9-inch monochrome display and compact form factor, but included a 1.44 MB SuperDrive and optional internal SCSI hard drive. It was the first Macintosh to sell for under $1,000, making it a popular choice for schools and home users.
The '''Macintosh Classic''' is a compact Macintosh introduced on 15 October 1990 as the first Macintosh to sell for under US$1,000: $999 with a floppy drive only and 1 MB of RAM, or $1,499 with a 40 MB hard disk and 2 MB. It was discontinued on 14 September 1992.<ref name="lem">{{cite web |url=https://lowendmac.com/1990/mac-classic/ |title=Mac Classic |publisher=Low End Mac |access-date=2026-09-30}} Dates, prices, code names XO and Civic, order number M0420, System 6.0.7 to 7.5.5, ROM disk, brightness control panel, memory card.</ref> It has the 7.8336 MHz 68000 of the [[Macintosh SE]], a 1.4 MB floppy drive and an optional 40 MB hard disk, with one ADB port and no expansion slot other than the connector for Apple's memory expansion board.<ref name="sscl">Apple Computer, ''Macintosh Classic/Classic II/Performa 200 Service Source'', Specifications, pp. 1-8 (PDF pp. 5-12). Hosted as [[:File:Classic ii.performa 200.pdf]]; see [[Macintosh Classic/ Classic II/Performa 200 Service Source]].</ref> The front-panel brightness knob of earlier compacts is gone; brightness is set from the Brightness control panel.<ref name="lem" />


== General Maintenance ==
== Specifications ==
For cleaning, battery maintenance, board inspection, and power supply tuning, refer to the [[Macintosh Classic General Maintenance]] page.
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:85%;"
|+'''Macintosh Classic specifications (Apple)'''<ref name="sscl" />
! Item !! Specification
|-
| CPU || Motorola 68000, 7.8336 MHz, 32-bit internal data bus
|-
| RAM || 1 MB, expandable to 4 MB (120 ns or faster SIMMs)
|-
| ROM || 512 KB
|-
| PRAM || 256 bytes
|-
| Expansion connector || 44-pin connector for the optional memory expansion board, which carries two SIMM connectors
|-
| Floppy || Internal 1.4 MB; optional external 800 KB or 1.4 MB (DB-19)
|-
| Hard disk || Optional internal 40 MB; external SCSI (DB-25)
|-
| ADB || One port, mini DIN-4
|-
| Serial || Two RS-422 ports, mini DIN-8
|-
| Sound || Four-voice, 8-bit D/A conversion, 22 kHz sampling; the headphone jack is fed from the mono output, and Apple notes that the Classic does not provide true two-channel output
|-
| Video || 9-inch diagonal, 512 × 342 bit-mapped monochrome
|-
| Line voltage || 100–120 V AC
|-
| Frequency || 47–63 Hz, single phase
|-
| Maximum power || 100 W
|-
| Dimensions || 13.2 × 9.7 × 11.2 in (33.6 × 24.6 × 28.5 cm)
|-
| Weight || 16–17.1 lb (7.3–7.8 kg), excluding an internal hard disk
|}
 
The specification pages give only the 100–120 V rating, but the exploded view lists 220 V versions of the power/sweep board as well as 110 V ones (see [[#Service parts|Service parts]]).<ref name="ssclev">''Macintosh Classic/Classic II/Performa 200 Service Source'', Exploded View (PDF p. 115).</ref>
 
== Memory ==
The logic board carries 1 MB, soldered, and has no SIMM sockets. Apple's optional memory expansion board, for the Classic only, plugs into the 44-pin connector and carries another 1 MB soldered plus a pair of SIMM connectors and a jumper. Fitting two 256 KB or two 1 MB SIMMs (120 ns or faster) and moving the jumper takes the machine to 2.5 MB or 4 MB.<ref name="sscl" /><ref name="sscup">''Macintosh Classic/Classic II/Performa 200 Service Source'', Upgrades, Memory Expansion Board and Memory Upgrade, pp. 1-6 (PDF pp. 68-73).</ref>
 
Apple's symptom chart for a Sad Mac at start-up names the two usual mistakes: the jumper on the memory expansion board must be set to "SIMMs" or "No SIMMs" to match what is fitted, and a 4 MB Classic needs eight-chip SIMMs, because 1 MB SIMMs with fewer than eight chips will not work in the Macintosh Classic.<ref name="ssclts">''Macintosh Classic/Classic II/Performa 200 Service Source'', Troubleshooting, Symptom Charts, Miscellaneous, pp. 12-14 (PDF pp. 25-27).</ref> Low End Mac advises against buying a Classic without the memory expansion board unless another is available.<ref name="lem" /> The full procedure is on [[Macintosh Classic Memory Upgrade Guide]].
 
== The ROM disk ==
Holding Command-Option-X-O at start-up boots the Classic from a 357 KB read-only volume in ROM named "Boot Disk", holding System 6.0.3 and Finder 6.1.x. Its only control panels are General, Brightness and Startup Disk, and nothing can be added to it. Low End Mac describes booting from ROM as a feature unique to the Classic.<ref name="lem" />
 
== Service parts ==
{| class="wikitable styled-table" style="width:80%;"
|+'''Classic family service parts (Apple exploded view)'''<ref name="ssclev" />
! Part !! Apple part number
|-
| Logic board (Classic, 1 MB) || 661-0596
|-
| Power/sweep board, 110 V || 661-0597 (Rev. A), 661-0651 (Rev. B)
|-
| Power/sweep board, 220 V || 661-0599 (Rev. A), 661-0652 (Rev. B)
|-
| CRT and yoke assembly || 076-0546
|-
| Floppy drive || 661-0474
|-
| Hard drive, 40 MB || 661-0216
|-
| Lithium battery || 742-0011
|-
| Floppy drive cable || 590-0167
|-
| Hard drive power cable || 590-0521
|}
The 110 V and 220 V power/sweep boards are different parts; check which one you have before using a capacitor list.


== PCB Schematics & Service Manual ==
== Service manual and schematics ==
<pdf width="800" height="500">File:Classic ii.performa 200.pdf</pdf>


The Macintosh Classic includes two main PCBs: a unified logic board and an analog board. Below are the schematics and Apple’s official service manual.
Apple's ''Macintosh Classic/Classic II/Performa 200 Service Source'' (115 pages, embedded above) is described at [[Macintosh Classic/ Classic II/Performa 200 Service Source]]. Its Light Meter Setup covers three meter models (R77, L-248 and 246).<ref name="sscl" />


=== Apple Service Manual ===
The manual settles two points for this machine. The clock battery is lithium and is replaced below 3.0 V, measured on the 10 V DC range with the cover off, the CRT discharged and the logic board removed.<ref name="ssclbatt">''Macintosh Classic/Classic II/Performa 200 Service Source'', Additional Procedures, Battery Verification, pp. 1-4 (PDF pp. 81-84).</ref> And there is no power-supply voltage adjustment: the Adjustments chapter covers light meter setup, video and yoke only, so the rail-tolerance figures published for the Macintosh 128K, 512K and Plus do not apply here.<ref name="ssclad">''Macintosh Classic/Classic II/Performa 200 Service Source'', Adjustments, pp. 1-24 (PDF pp. 90-113).</ref>
All Apple Service Manuals are archived on the [[Apple Service Manuals]] page. You can find the Classic Service Manual here: [[File:Macintosh_Classic_-_Classic_II.pdf|center|thumb|Apple Service Guide - Macintosh Classic]]


=== Logic Board & Analog Board Schematics ===
The cover comes off after removing four Torx case screws and separating the cover with a case spreader; the two black screws go in the bottom and the two silver screws in the top when it is refitted. Apple warns that the edges of the metal chassis may be sharp.<ref name="sscltA">''Macintosh Classic/Classic II/Performa 200 Service Source'', Take Apart, Cover, pp. 1-3 (PDF pp. 30-32).</ref>


=== Logic board and power/sweep board ===
{| class="wikitable" style="width:50%; text-align:center;"
{| class="wikitable" style="width:50%; text-align:center;"
|+'''Macintosh Classic PCB Schematics'''
|+'''Macintosh Classic PCB images'''
|-
|-
! style="background-color:#f2f2f2; width:30%;"| Logic Board
! style="width:50%;"| Logic board
! style="background-color:#f2f2f2; width:30%;"| Analog Board
! style="width:50%;"| Power/sweep board
|-
|-
| [[File:MacintoshClassicLogicBoard.jpg|thumb|center|250px|Macintosh Classic Logic Board]][[File:MacintoshClassic LogicBoard Schematic.pdf|center|thumb|Macintosh Classic Logic Board Schematic]]
| [[File:MacintoshClassicLogicBoard.jpg|thumb|center|250px|Macintosh Classic logic board]][[File:MacintoshClassic LogicBoard Schematic.pdf|center|thumb|BOMARC schematics of the Classic power/sweep boards and logic board]]
| [[File:MacintoshClassic AnalogBoard.jpg|center|thumb|250x250px|Macintosh Classic Analog Board]][[File:Classic Analog Board Schematic.pdf|center|thumb|Macintosh Classic Analog Board Schematic]]
| [[File:MacintoshClassic AnalogBoard.jpg|center|thumb|250x250px|Macintosh Classic power/sweep board]]
|}
|}


== Capacitor Replacement Guide ==
Apple's manual calls the Classic's combined power supply and deflection board the power/sweep board.<ref name="sscltA2">''Macintosh Classic/Classic II/Performa 200 Service Source'', Take Apart, Power/Sweep Board, pp. 4-11 (PDF pp. 33-40).</ref> BOMARC's schematics of the two 110 V power/sweep boards, 820-0395-A and 820-0525-A, are at the start of [[:File:MacintoshClassic LogicBoard Schematic.pdf]] (PDF pp. 1–3 and 4–6), ahead of the logic board, 820-0390-B (PDF pp. 7–11). They were drawn by BOMARC Services from the boards and are not Apple documents.<ref name="bomarc">BOMARC Services, schematics of the "Macintosh Classic" series computer power supply / 9-inch monitor, boards 820-0395-A and 820-0525-A (PDF pp. 1–3 and 4–6), and of the Classic logic board 820-0390-B (PDF pp. 7–11). Hosted as [[:File:MacintoshClassic LogicBoard Schematic.pdf]]. Reverse-engineered, not Apple documentation.</ref> The file [[:File:Classic Analog Board Schematic.pdf]] is not a Classic document: its internal title is ''SE30_Analog_Board'', and it shows an analogue board fed from a separate power supply, as in the [[Macintosh SE/30]].
Full details on logic and analog board recapping can be found at the [[Macintosh Classic Capacitor Replacement Guide]].


== Retrobrite ==
== Maintenance, capacitors and troubleshooting ==
To restore the beige color of the Classic’s case, refer to the safe plastic whitening procedures outlined on the [[Retrobrite]] page.
* [[Macintosh Classic / Classic II General Maintenance]]: cleaning, the lithium battery and its 3.0 V replacement threshold, and the rails.
* [[Macintosh Classic Capacitor Replacement Guide]]: values and positions.
* [[Macintosh Classic / Classic II Troubleshooting]]: symptom-led diagnosis.
* [[CRT Discharge Procedure]]: read before opening the case.
* [[Retrobrite]]: for a yellowed case.


== Troubleshooting ==
''The Dead Mac Scrolls'', a component-level reference for the earlier compacts, does not cover the Classic: its author says the Classic, Classic II and other machines still under warranty when it was written are not covered in that edition.<ref name="dms">Larry Pina, ''The Dead Mac Scrolls'', Peachpit Press, 1992, Introduction (PDF p. 8). Hosted as [[:File:The Dead Mac Scrolls 1992.pdf]]; see [[The Dead Mac Scrolls]].</ref>
For diagnosis and solutions to common issues including no startup, checkerboard patterns, floppy drive problems, and failed PRAM batteries, see the [[Macintosh Classic Troubleshooting]] guide.
 
Sad Mac codes are decoded on [[Sad Mac Error Codes]] and with the [[Sad Mac Decoder]].
 
== Related pages ==
* [[Macintosh SE]]
* [[Macintosh SE/30]]
* [[Macintosh Classic II]]
* [[Macintosh Color Classic]]
 
== References ==
<references />


[[Category:Apple Vintage Computers]]
[[Category:Apple Vintage Computers]]
{{Navbox-AppleVintage|state=collapsed}}
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