Mitsubishi MP 286L Laptop Teardown

Mid-quarantine project: teardown & documentation of 1989 laptop

Much in the style of iFixit, but with my commentary, herein is the documentation of a 1989 Mitsubishi MP 286L laptop. Affectionately referred to online as a luggable, this laptop contained a few fun parts I'd not seen in a laptop before [MiniScribe HDD, whole PSU, full size mechanical keyboard]. I'll talk about the parts, process, useful sites on finding info on old electronics, and most likely pose a few questions as the documentation goes along.

Tools:

(1) screwdriver [phillips #0]
(1) pry tool [any]

Rule of thumb for screws: the pointy ones go in plastic and the machine screws connect metal parts.

The case:

This laptop was given to me from a family member and I've lugged it around for at least 5 years now. It was kept because of its [now] unconventional shell, which I plan on modifying into a cyberdeck build. If you've not heard of a cyberdeck, they fun builds you should check out. Part of my hope with this is that someone will need this info to make a project go smoother or a repair even. Repair seems less likely though! Anyway, here it is.

Remove the screen:

The screen removal process was convoluted. The secret, remove the cover of the power buttons and there is a screw connecting the grounding wire for the screen to the body that can be access there. Remove that, then close the lid, flip over the unit, and remove all of the screws on the bottom of the body. Flip back over and screen with top half of body casing should lift away.
Caution: one longer connector for the screen will still be attached to body, simply unplug from connector on body.

Body disassembly:

Note picture on right has the monitor screen cable still attached in black. I removed all screws around the keyboard next. Allowing for it to be removed completely. It really comes down to any screws you see at this point. Pull them out, make piles of similar, and note were they came from. [meta: I debated editing the photos with nice colored boxes and arrows relating to captions, but without a good blog framwork that seemed too daunting for a one day project...]

If anyone happens to know a good way to interface with this keyboard or resources to figure it out, please leave a comment about that. I plan on reusing the keyboard in my cyberdeck build! I would assume it is just a regular switch matrix I can control with an attiny or teensy microcontroller depending on budget/time.

Continuing to remove things, we see the internal architecture is more like a desktop than a modern laptop. Components are stacked horizontally and even vertically. The joys of designing a device with the large bits of yester-year. [Meta: it's fascinating to compare the design restrictions in place compared to modern devices. The modular pieces give design inspiration to the cyberdeck build.] The below pictures show the small "desktop" like design under the diagonal metal bracketing. First, the stacked graphics card, very similar to modern desktop design [connection wise]. Then, the metal bracketing was removed as well as the PSU. Lastly, the vertically connected bit is pulled out to show the connectors along it. [Meta: if anyone knows an easy to integrate photo slider for blogger, lmk...]

The PSU was nothing special, the wires pull right out and a few screws. It did happen to smell like burnt hair though... Maybe that is the cause of some of the issues that came with this laptop.

This was the most interesting part of this disassembly. The 3.5' floppy drive and MiniScribe HDD sat on a bracket above the motherboard across the center of the computer. The HDD does not boot, not sure the issue there. I found a site [mitsubishipcdatabase] which the author described his path to fixing one. 

The above two pictures show the motherboard where I could read all chip markings. [Meta: If not visible online, I may adjust or message me for full-res pics.]

Left is the base with only the piezo speaker left. Not too exciting. Next, I'll move to the screen.

The screen:

The screen is a bit more precarious. Or should I say I am when dissecting a monitor. I'll never forget the words of my 4th grade teacher, who part time did computer repair with his sons, "...be careful if you ever take apart a PC monitor, they're easy to break and can have chemicals you don't want to interact with..." It may have been more to control an over-zealous 4th grader than a hard rule, but it's been useful. Twist those little knobs on the side to reveal the screws holding the monitor to the upper half of the body. Some bits will slide off when removing the screws.

The Use the pry tool, starting at the base of the monitor and working upward, to remove the bezel from the display. The display controls are connected to the front bezel, two potentiometers and a slider, held on by two screws. 

Monitor controller of some sort, potentially power, on the right side above. [Meta: If you know of a good way to interface with a monitor like this, please comment. I'd like to reuse this monitor in some future project.] I believe this is a grey-scale monitor, but the computer does not power up past some text asking for a floppy disk. 

Thanks for browsing my disassembly log of the 1989 Mitsubishi MP 286L luggable laptop! It was a fun process of setting up a mini photo studio to photograph this process. Please leave any comments, especially those on my questions, below. I plan on following this up with a break down of a slightly newer laptop I have during the covid quarantine. We'll see how that goes...