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Tech Specs

Backlit Mac Portable

Daniel Knight - 1991.02.11

Apple took the “underwhelming” Mac Portable, replaced the non-backlit 9.8″ 1-bit 640 x 400 pixel active matrix screen with a backlit display, increased base RAM to 2 MB or 4 MB, lowered the memory ceiling to 8 MB, and replaced expensive the SRAM (static RAM) chips with less-expensive pseudo-SRAM.

Macintosh Portable

One negative side effect: pseudo-SRAM and backlighting draw more power, reducing battery life.

The huge size and massive weight of the otherwise-impressive Portable make us call it a Limited Mac. Bear in mind that the Portable was never intended as a laptop computer, but as a portable version of the desktop Mac. With a 16 MHz CPU, it was a very nice performer under System 6 and System 7.

The Portable was replaced by the first PowerBook models (100, 140, 170) in October 1991.

  • Got a Mac Portable or PowerBook? Consider joining the PowerBooks email list.
  • Our System 6 List is for those using Mac System 6.

Details

  • introduced 1991.02.11, discontinued 1991.10
  • Gestalt ID: 10
  • model number: M5126

Mac OS

  • requires System 6.0.4 to 7.5.5 (see caution on wake up crash caused by newer drivers)
  • addressing: 24-bit only

Core System

  • CPU: 16 MHz 68HC000
  • ROM: 256 KB
  • RAM: 2 MB, expandable to 8 MB using a special pseudo-SRAM card (only one slot)

Performance

Graphics

  • display: 9.8″ 1-bit 640 x 400 77 ppi

Drives

  • hard drive: 40 MB 3.5″ hard drive standard, uses special low power Connor drive with special connector (can only use standard SCSI drives with a special, costly adapter)
  • floppy drive: 1.4 MB double-sided

Expansion

  • ADB ports: 1 for keyboard and mouse
  • serial ports: 2 DIN-8 RS-422 ports on back of computer
  • SCSI ports: DB-25 connector on back of computer
  • proprietary modem slot

Physical

  • size (HxWxD): 4.05″ x 15.25″ x 14.83″
  • weight: 15.8 lb.
  • power supply: 5W, 13 amps
  • batteries: 9V “transistor” battery for PRAM, 6V 5Ah sealed lead-acid for power (over 2 lb.)

Tips

  • One user has reported success replacing a dead Conner CP-3045 hard drive with a standard Conner CP-3044 that had been formatted under System 6.0.8.
  • You can use a PowerBook 100-series AC adapter to run the Portable without its internal lead-acid battery. However, you will lose PRAM settings if you unplug the power (date, time, cache size, etc.)
  • Godwin <godwin@unixg.ubc.ca> says, “If the acid battery dies, one can bypass it and convert the Portable into a luggable. One needs 2 AC adapters – the original one and a 9V DC adapter. Take out the 9V DC battery and replace it with a 9V 1A power adapter. Then remove the battery and cover (there is a switch at the battery cover which we need to disable). Plug the two adapters in and viola! one of the sleekest Macs on anyone’s desktop!”

Online Resources

Online Profiles

Battery/Power Links

Cautions

  • Never use a version of Apple HD SC Setup newer than 7.3.1 (which comes with System 7.0.1) or your Portable will crash while waking from sleep mode.
  • The Mac Portable does not provide SCSI termination power, depending on external SCSI devices to provide it. For more details, see SCSI Termination Power.
  • Macs with black-and-white only displays (1-bit, no grays) may find Netscape Navigator 3 makes it impossible to view some pages and sites. The workaround is to use Navigator 2.
  • Battery becomes unusable if discharged below 5.4V – keep it charged!
  • Hard drive will not spin up without a charged battery installed.
  • Modem port limited to 57.6 kbps (printer port may be faster); use of a 56k modem on the modem port may limit throughput. See 56k modem page.
  • Apple has discontinued support and parts orders for this model. You may be able to find dealers with parts inventory either locally or on our parts and service list.

Keywords: #macportable #backlitmacportable

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