Mitsubishi mp 286L

"At last, a laptop computer that doesn't compromise on readability, speed, power or expandability for the sake of portability. The mp 286L has the largest, brightest display available on any laptop. Its backlit LCD display can be read from several feet away in virtually any light. The mp 286L is so remarkable that once you've started to use it, you may never want to return to a desktop computer again!"

-Commercial retail box advertisement, 1988

We know Mitsubishi often for their cars, but they're also known to produce quite a lot more than that. pencil lead, forklifts, AC's, even naval ships and fighter planes at some point. But very few people know about the Mitsubishi mp 286L, the Asian conglomerate's first foray into the business computer market.

Their timing was rather unfortunate though, as it was not only near the time when technological growth would make them eat dust, but also around the time MiniScribe, who are the ones that supplied the hard drives, were about to be exposed as frauds for shipping bricks in boxes, instead of the hard drives that make up these units.

They grew outdated in the following of the 90's, and have fallen into obscurity since.

Like all laptops of the era, this one has a low capacity hard drive, an HD 3.5" floppy drive, old cable standards such as serial and parallel, and just being ridiculously heavy.

everything is inside a black, hard plastic casing with a sleek finish. from the bulky clam-shell display to the flat bottom of the unit, it's really built like a Mitsubishi.

But coming into a stiff competition, They decided to make it stand out with some of their unique design choices. To start, it has no battery, and it can only be powered directly on via AC power cable, so you can't use it on any public transportation.

They also did some bizarre work on the keyboard, making the function and arrow keys half-sized horizontally, and rearranging them so that the arrow keys are in the top right corner, and the last 4 function keys placed above the first 4, across from the arrow keys, making them easy to miss and awkward to use.

Because of the short lived history of these things, alongside their strange form factors, it was, and still is, incredibly difficult to find any information on these lap crushers. I took it upon myself to make this ifixit page so anything new that is found about the mp 286L can be put here, making everything available in one place. any and all useful additions are welcome!

• Brand: Mitsubishi
• Model form factor: MAXY (IBM compatible(see Software Things for details))

Model Numbers:

• 210 (with dual floppy 3.5" drives
• 220 (1 floppy drive, 1 hard drive)
• 240EVP (with an EGA screen)
• MP-2120* (*I have this one, same as 220)
• MP-2130

Weight: ~10-16 lb (4.5-7.0 kg)

Original Price Range: 1750$ - 5000$

Size: (WxHxD) 12.3" x 3.5" x 14.2"

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Processor: Intel 80286

• Clock rates: 5, 6, 8, 12 (standard), 16*, 20*, 25MHz* (*later models released by Fujitsu and AMD)
• Processing power: 6-12MHz (1 wait state for anything above 8MHz)
  • works with an optional Intel 80287 math co-processor

Memory: 640 kb of RAM

• expandable to 2.6 mb with proprietary memory card (more info to be found on it)

Power:

* Whole power supply unit:

• Model No.: PC21WA (Power supply circuit type by model no. is TBD)
  • Voltage needed: 115V, 220V-*240V (*230V is the factory setting)
  • Power Cable: Standard IEC AC power cable within the above voltages
• CMOS: Proprietary Varta Ni-Cd battery (just a fancy name for a time bomb)
  • Volts & Amps: 3.6v, 170mAh

Built-in Storage: Miniscribe Hard Drive* (*Check links in the references for pictures)

• No. of drive types: 0-47 (this is shown and requested in the setup disk software)
• Model No. : M8425* (*often shortened to just 8425)
  • interface: ST506
  • Recording methods: MFM, SCSI* (*uses a different controller card)
  • Capacity: 20-21 MB
  • Phase: DTF
  • Platter size: 3.5"
  • No. of Heads: 4
  • No. of Cylinders: 615

Internal Floppy drive: 3.5"

• Disk capacities: 720 kb (standard), 1.44 mb (High Density)
  • It's one or the other when comparing units

Sound: 1x 15 mm x 2 mm Piezo speaker plate

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I/O: all of these are connected to the machine by 4 proprietary card slots

• Serial ports: 2x male-end 9-pins (RS-232)
• CRT Display out: 1x female-end 9-pin
  • Can connect to an external 16-color CRT display
• Network Inputs: 1x line, 1x telephone jacks (Both shaped like RJ45, not RJ11)
  • works with an optional 2400 bps modem which can be installed inside the machine (there's even an installation guide!)
• External drive: 1x 26-pin floppy drive* (*female port end)
  • connects with 5.25" 1.2mb or extra 3.5" 1.44mb floppy drive
  • Cable Pinout
• External input device: Female bus port end (for number pad mentioned in Included Software section)
• Printer Cable: 1x 25-pin parallel (Centronics)
• Back-Switches*: 2x arrays of 4 switches (for small, temporary changes after set up)
  • DTS-4 to the left of FDD port (if looking from the back)
  • DPS-4 to the right of CRT port (if looking from the back)
    • 6 levers present by CRT on MP-2130 Model (why it's different is unknown)

Keyboard:

• No. of keys: 86
• Key layout: Custom AT
• Design: Mechanical (it feels nice :/)

Display:

• Type: Cold CRT, back-lit passive-matrix LCD (with neutral twist nematic)
  • Knobs and switch on bottom right corner of front bezel control back light and blacks-on-whites contrast configuration
• Dimensions: (WxH) 9" x 6.5", 11" diagonal
• Pixel Resolution: 640 x 200-400, for graphics and text respectively
• Character resolution: 80 characters/line
• compatible aspect ratios: EGA and CGA
  • Some documentation mentions a unique 'Hercules' resolution mode. More information on that soon...

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Included In-Box Software:

• Setup & diagnostics (for any pre-POST configurations)
• utilities (for mouse and/or number pad, as well as dial-up connection and system checkup)
• MS-DOS 3.30 driver
• WordPerfect (circa 1990, "For IBM Personal Computers")
  • Some units are found with a Cheat sheet for keyboard shortcuts

BIOS: Phoenix 80286/80386 ROM BIOS version 3.10 (IBM BIOS clone)

• Fun Fact: This is the same BIOS type used in the iconic Compaq Portable Laptop

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Below is a checklist of included in-box documentation

KEY:

[] (not accessible to me at all)

[-] (readily accessible but not scanned)

[/] (scanned and uploaded)

• [-] MS-DOS 3.30 Quick Reference
• [] MP 286L Quick Reference
• [] MP 286L Internal 2400 BPS Modem Installation Guide (as mentioned before)
• [] MP 286L User's Guide
• [] MS-DOS 3.30 User's Guide

Once again, All helpful and useful additions are welcome! Thank you!

Sources:

BCBarlow's Teardown Guide (*new, updated link)

This Machine on The Center of Computing History

Google Books search on the MP 286L (THIS WORKED MIRACLES FOR ME)

Pictures: Courtesy of Higher Intellect's Vintage Computing Wiki

Pictures of the laptop

Pictures of its fixed hard drive

Downloads:

Utilities software download

BIOS Setup and diagnostics download

Another setup download from a troubleshooting forum

All downloads made possible by VOGONS Vintage Driver Library

YouTube videos

Russian unboxing video of a used (but working) unit

MikeTech's repair and exploration of one from VCF (go check this guy's other stuff as well. It's cool!)

eBay listings:

Laptop with number pad accessory and carrying case (Sold but still viewable)

Laptop with included Manuals, discs, and carrying case (No longer exists...)

Laptop with bonus power cord and all documentation (same model as the one I have)

Reddit Threads: On r/retrobattlestations

Troubleshooting thread regarding system FDISK

Followup thread on the CHECK SUM FAILED issue (take your time reading these)