Macintosh Portable
The Macintosh Portable is Apple's first battery-powered Macintosh, sold from September 1989 to October 1991. It has a 16 MHz 68HC000, an active-matrix LCD, a full-size keyboard with a trackball that can sit on either side, and a sealed lead-acid battery that runs it for up to ten hours.[1][2] Apple introduced a backlit version, the M5126, in February 1991; it is described on Macintosh Portable (backlit).[3]
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| Macintosh Portable with its power adapter (Hannes Grobe, Wikimedia Commons, CC BY 3.0) | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Portable computer |
| Released | 20 September 1989 (M5120); 11 February 1991 (backlit M5126) |
| Discontinued | 21 October 1991 |
| Intro price | US$5,799; US$6,400 with 40 MB hard disk (1989) |
| CPU | Motorola 68HC000 at 15.6672 MHz |
| Memory | 1 MB static RAM on the logic board; one RAM expansion slot |
| Storage | 1.4 MB floppy drive; optional 40 MB SCSI hard disk or second floppy drive |
| Display | 10-inch active-matrix LCD, 640 × 400, monochrome; backlit on the M5126 |
| Sound | — |
| ROM | 256 KB |
| Power | 6 V sealed lead-acid battery; 9 V backup battery; 7.5 V power adapter |
| Dimensions | 15.25 × 14.83 in, 4.05 in high at the rear |
| Weight | 13.75 lb (6.25 kg) without hard disk; 15.75 lb (7.16 kg) with |
| OS / Firmware | System 6.0.4 to System 7.5.5 |
| Successor | PowerBook 100, 140 and 170 |
| Model no. | M5120; M5126 (backlit) |
Restorers report that a Portable will not run without a healthy main battery, that its power circuitry is easily damaged, and that the logic boards suffer from leaking capacitors and from leaking 9 V backup batteries. David Cook, who repaired five, recommends getting experience on other Macs before tackling one.[4][5]
Models
edit| Item | M5120 (original) | M5126 (backlit) |
|---|---|---|
| Introduced | 20 September 1989[2] | 11 February 1991[6] |
| Logic board | Static RAM board, 820-0219-A[7] | Pseudostatic RAM board, 820-0256[7] |
| Wait states | 1 | 10[1] |
| RAM expansion | Static RAM cards, to 9 MB | Pseudostatic RAM cards, to 8 MB[8] |
| Display | Reflective active-matrix LCD, contrast adjusted in software | Backlit active-matrix LCD with CCFL and inverter board, brightness adjusted in software[1] |
| Power regulation | Separate hybrid module on the logic board | Equivalent circuit built on the logic board[5] |
Specifications
edit| Item | Specification |
|---|---|
| Processor | Motorola 68HC000, 16-bit CMOS, 15.6672 MHz; 24-bit address bus, 16-bit data bus |
| RAM | 1 MB in thirty-two 32K × 8 static RAM chips, 100 ns; addressing supports 9 MB. 1 MB card for the static board; 3 MB card for the backlit model |
| ROM | 256K in two 128K × 8 chips, 150 ns |
| PRAM | 128 bytes |
| Video RAM | 32K static |
| Display | 10-inch diagonal active-matrix LCD, 640 × 400 pixels, 75 dpi, 0.33 mm dot pitch |
| Storage | Internal 1.4 MB floppy drive; optional internal 40 MB hard drive |
| Ports | External floppy (DB-19); SCSI (DB-25, 1.5 MB/s); ADB; two RS-422 serial (mini DIN-8); phone jack for the optional modem; power adapter; stereo sound out; video (DA-15) for external video devices |
| Keyboard | 63 keys, ADB; trackball or 18-key numeric keypad either side |
| Sound | Apple Sound Chip, filtered by two Sony sound chips |
| Main battery | Sealed lead-acid, 6.5 V; up to 10 hours |
| Backup battery | 9 V transistor battery |
| Power adapter | Input 85-270 V AC, 48-62 Hz; output 7.0-7.6 V (7.5 V nominal), 5 mA to 2.0 A (1.5 A nominal) |
| Size | 15.25 in (387.35 mm) wide; 14.83 in deep; 4.05 in (102.87 mm) high at the rear and 2.10 in at the front; 11.0 in high with the display open |
| Weight | 13.75 lb (6.25 kg) without hard drive; 15.75 lb (7.16 kg) with hard drive |
Apple's figures conflict in places. The specification gives the main battery as 6.5 V, while the exploded view lists it as the "6 V Main Battery", 076-0376, and Low End Mac gives 6 V.[1][3] The depth is printed as "14.83 in. (365.25 mm)", and 365.25 mm is 14.38 in.[1] Apple's specification page gives the adapter input as 70-270 V; the Service Source gives 85-270 V.[2][1]
Hardware
editPower system
editThe Portable runs from its main battery, and the adapter charges that battery. The power manager (PMGR) chip on the logic board controls power, sleep and charging and holds the 128 bytes of PRAM.[1][9] Low End Mac warns that the hard disk will not spin up without a charged battery fitted, and that a battery discharged below 5.4 V becomes unusable.[6] A switch at the battery cover connects the logic board to the main battery when the cover is fitted and to the 9 V backup battery when it is off, and both power wires to logic board connector J17 are joined in Apple's harness.[4] Apple warns that leaving the battery cover off with the main battery out keeps power on the logic board, so modules removed or fitted in that state can be damaged.[1]
On the M5120, a separate hybrid module on the logic board provides the always-on 5 V rail, switches the 12 V and −5 V supplies, charges the battery and cuts the machine off at low battery voltage. Androda, who made a replacement, describes the originals as failing from capacitor leakage and from cracked coatings on their trimmed resistors.[10] The M5126 has the same circuit built directly on the logic board, next to capacitors around the keyboard and trackball connector.[5]
Memory
editThe logic board carries 1 MB, and one slot takes a RAM card. Static RAM cards from 1 to 8 MB fit the original board, to a 9 MB maximum; the backlit board takes pseudostatic cards from 1 to 7 MB, to 8 MB. The two card types are not interchangeable. Apple's check is the RAM connector: a notched connector takes a pseudostatic card.[1][8] The Portable runs in 24-bit addressing only and has no virtual memory.[3][8]
Display and video port
editThe 640 × 400 active-matrix panel is made by Hosiden.[3] Apple accepts up to five pixels that never turn on; six or more, or any pixel that stays black, means a new display.[1] The DA-15 video port on the back is not a VGA port; David Cook warns never to connect a VGA cable directly to it, and uses a purpose-made adapter for an external monitor.[4]
Storage
editThe internal hard disk is a Conner CP-3045 with a proprietary connector; a standard SCSI drive needs an adapter.[3] Owners report that the Conner drives' seals and head bumpers turn to goo.[5]
Common problems
edit- No power, or the machine shuts down at once, with a flat or missing battery; see Macintosh Portable Battery Replacement.
- Leaking surface-mount electrolytic capacitors and broken traces; see Macintosh Portable Capacitor Replacement Guide.
- A leaking 9 V backup battery corroding traces near the memory chips.[5]
- A failed hybrid module (M5120) or regulation circuit (M5126), which can put adapter voltage on the 5 V rail; owners link this to dead power manager and SWIM chips.[5]
- Damage from the wrong power adapter or a badly wired bench supply.[4]
Fault-finding is on Macintosh Portable Troubleshooting.
Maintenance and repair
editDocumentation
edit- Macintosh Portable Service Source: Apple's service manual for both models.
- Apple Memory Guide: RAM card types and sizes.
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Related pages
editReferences
edit- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Apple Computer, Macintosh Portable Service Source (151 pp., PDF created 19 January 1996), hosted here as File:Macintosh_portable.pdf (see Macintosh Portable Service Source). PDF page numbers: Specifications pp. 5-15; Symptom Charts pp. 18-37; Take Apart: Main Battery pp. 45-46, Backup Battery pp. 47-49, LCD Display (Backlit) pp. 82-91, Logic Board pp. 92-98; Upgrades: RAM Expansion pp. 119-123, Backlit Display Upgrade pp. 127-131; Battery Verification pp. 133-135; Adapter Verification pp. 136-137; Exploded View p. 151.
- ↑ 2.0 2.1 2.2 Apple, "Macintosh Portable: Technical Specifications" (retrieved 2026-10-02). Introduced 9/20/1989, discontinued 10/21/1991; 68000 at 16 MHz, 16-bit data path; 1 MB on the logic board, one RAM slot, 1-8 MB; battery type lead acid; 70-270 V; original system software 6.0.4; Gestalt ID 10.
- ↑ 3.0 3.1 3.2 3.3 3.4 Low End Mac, "Mac Portable" (retrieved 2026-10-02). Introduction 20 September 1989 at US$5,799 (US$6,400 with 40 MB hard drive); price cuts of 1 April 1990; discontinued 21 October 1991; model M5120; System 6.0.4 to 7.5.5; 24-bit only; Hosiden LCD; Conner hard drive with special connector; 9 V transistor battery for PRAM; M5137 sealed lead-acid battery, 6 V 5.5 Ah; M5136 power adapter, 7.5 V 1.5 A. Secondary source.
- ↑ 4.0 4.1 4.2 4.3 TinkerDifferent forum thread "Fixing a Macintosh Portable - What worked for me", David Cook and others, January to August 2026. Community repair report covering five Portables: battery dependence, PowerBook adapters, hybrid module, J17 bench-supply wiring, current draw, SWIM failures and sound crashes.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 TinkerDifferent forum thread "GOTCHAS when buying a Macintosh Portable?", July 2023. Community experience from owners of several M5120 and M5126 machines: 9 V battery leakage, hybrid module, SWIM, Conner drive seals, power adapter capacitors.
- ↑ 6.0 6.1 Low End Mac, "Backlit Mac Portable" (retrieved 2026-10-02). Introduced 11 February 1991; model M5126; 2 MB or 4 MB RAM, expandable to 8 MB with a pseudo-SRAM card; cautions on battery discharge, hard drive spin-up and HD SC Setup versions. Secondary source.
- ↑ 7.0 7.1 Console5 TechWiki, "Macintosh Portable" (retrieved 2026-10-02). Capacitor lists for boards 820-0219-A (original) and 820-0256-03/820-0256-B (backlit). Secondary source.
- ↑ 8.0 8.1 8.2 Apple Computer, Apple Memory Guide (May 2000), hosted here as File:Apple Memory Guide (May 2000).pdf (see Apple Memory Guide). Portables pp. 1-2, Macintosh Portable and Backlit Portable (PDF pp. 98-99).
- ↑ TinkerDifferent forum thread "Portable and PowerBook 100 Technical Note: PRAM, Backlight, and ROM Diff", David Cook, January 2026. 128 bytes of PRAM held in the Power Manager; supported PRAM ranges; detecting the backlit model; identical ROM in both models. Secondary source.
- ↑ TinkerDifferent forum thread "Recreating Macintosh Portable Hybrid Module", Androda, February-March 2022. Functions of the hybrid module and its failure modes. Secondary source.