Tuesday, December 21, 2010

Toshiba T1000 Teardown

My favourite rare treat at Free Geek is taking apart unusual old equipment. (See e.g. Industrial Computer Teardown.) Forgive me for posting this stuff as frequently as I possibly can -- it's fun, it's interesting and I love writing about it.

Toshiba T1000 Cockpit View

This is a Toshiba T1000 laptop, circa 1987, one of the earliest popular portables that actually looked like a modern machine. Portable computing at this point looked pretty strange -- a few odd-shaped competitors were the Compaq Portable III (stay tuned for a future post about a hack of one of these), or even more unusually, the Linus Write-Top, both from the same year.

Toshiba had several other horses in the same race, including the T3200, following the lineage of larger "luggables" like the classic Osborne 1 in that they didn't contain batteries at all and needed to be plugged in.

The T1000 is notable in that it was actually portable, i.e. ran from battery power, and was mass-produced for a relatively low sale price (listed for $999 and generally available for less, according to Retro Thing). This was considerably ahead of its time -- it took Zenith a full couple of years to release the competing MinisPort with quite similar specs, though the Zenith used an extremely rare 2" floppy drive.
Sleek, portable, and attractive

This particular T1000 came into Free Geek Vancouver many months ago and has languished in the Incoming area for some time. A month ago I tried to power it up with no results. Last Thursday I tried again with a bit more dedication and still got nothing, so I decided to give it a proper White Bag funeral. Here are the results.
"If the suit is your uniform, then the briefcase is your shield."
(Let me apologize here for the poor quality of the photographs. I promise I'll start taking a real camera in with me.)

First some specifications. From http://en.wikipedia.org/wiki/Toshiba_T1000:
T1000 specification
Dimensions 12.2" W × 11.0" D × 2.05" H (310 × 280 × 52 mm)
Power 9 VDC, 1.1A (+ = core; - = shell)
Weight 6.4 lbs (2.9 kg)
Video CGA card
Sound PC speaker
Battery Rechargeable NiCd pack (1300 mAh)
Media 1 - 720 3.5" floppy disk drive
Mouse None
Keyboard Selectable between PC or AT (101)

There is no hard drive. DOS 2.11 is booted from a ROM (Read Only Memory) chip mounted on the motherboard; Toshiba probably intended to release upgrade chips with newer versions of DOS, but doesn't seem to ever have done so. (Microsoft still has a document describing how to upgrade to DOS 5.0 on their website here.) Aside from that, there is a single floppy drive for storage.

One upshot of having no hard drive, incidentally, is the battery life. This was apparently over 5 hours for the T1000 -- a number that has only recently become standard again after over a decade of 2- or 3-hour models.

Everything that makes the T1000 unique unfortunately makes for a pretty boring tear-down. It is almost entirely solid-state (i.e. the only moving parts are in the floppy drive) and it was designed without much consideration for modularity or upgrades (i.e. pretty much everything is built onto one circuit board).
The T1000, topless.
To get into the machine, it's necessary to remove the top including the LCD panel. (The big white plug just above the F1, F2, F3, F4 keys on the upper-left area of the keyboard is the only plug that connects to the LCD.) You can see the floppy drive at the upper left of the above photo. The battery pack used to live to the left of the floppy drive. I didn't get a picture of it.

Floppy drive and ROM chips (e.g. the one with the square white sticker)
(For some reason this is not a standard floppy drive, even though it's the same size, and even though Toshiba manufactured millions of standard floppy drives for other machines. There is only one connector, slightly smaller than a standard floppy data cable, and no separate power connector. In the late 1990s I used to have a similarly old T3200 that used the same floppy as this one, and it was impossible to find a replacement.)
Power block of motherboard

As I mentioned, the motherboard integrates more or less everything, making this a hard-to-service machine. There are really only five pieces that this disassembles into, barring the use of a soldering iron or claw hammer: the motherboard, the keyboard, the floppy drive, the LCD screen, and the external power supply. Pictured above is the power block of the motherboard, which takes the 9V input and breaks it into whatever the rest of the machine uses (probably 9V, 5V, and possibly 3.3V). I strongly suspect that the broken part of the machine is somewhere in this picture.

Here is the motherboard in the case, with everything else removed. The big square chip in the lower middle of the board is the CPU -- an 80C88, which is a particular revision of the 4.77MHZ 8088 chip that powered the IBM PC and XT line that (arguably) originally popularized home computing.

In case you're wondering -- why do we tear these apart? Well, if it worked, I would've made it my business to do something interesting around Free Geek with it. Since it's broken, and since it's stayed around for months, and since we don't have a museum mandate or a sustainable plan for museum-worthy gear, it needs to be scrapped. In order to do that we need to make sure there is no private information in it. Strange machines like this take a little more consideration because it's sometimes difficult to tell where that might reside.

Toshiba has a nice retrospective on this machine and others.

Sayonara, T1000.


  1. I am playing with my T1000 right now....it still works fine!
    I wonder if you have the ability to recognize which chip has the DOS2.2 on it? I also have a (dead) T1000XE whose DOS chip is a newer version (3.3) Wonder if the T1000 would benefit from a newer DOS chip? Ever tried something like this?
    Hillsboro, OR

  2. Hey Greg -- Interesting idea. Looking at the Toshiba specs for the two side-by-side:
    ...they're actually pretty different products, despite the similar model numbers.

    However, all the ROM-DOS systems I've toyed with have two chips for bios, and two for ROM-DOS. The BIOS takes care of most of the hardware-specific differences and the ROM-DOS won't vary much from system to system. The ROM-DOS chips should be labeled.

    Honestly, I don't know enough about the workings of ROM-DOS to guess whether it would work or not. If you want to give it a crack, I'd at least look up the chip model numbers to make sure they're pin compatible. If so, you're at least unlikely to destroy anything by trying.

  3. I also have a working T1000. Had to clean the motherboard and replace the battery to get it to work tho.

    It seems when the battery dies, it may leak a bit of conductive fluid on the mainboard. It's hard to see, everything looked clean, but if you use a multimeter you'll notice right away as PCB's shouldn't be conductive. :)

    After cleaning that it worked like a charm. Another little unknown fact is that the rom chip in the T1000 is 512KB altho only 256KB is used.

    Still looking for more documentation. I don't have the original manuals. Hoping they contain more information on how to use the ROM DOS / EMS Card I/O registers directly.

  4. I think my T1000 might work if it had a battery plugged in. There are four pins for the battery connector. If anybody knows how the battery is wired (4 in parallel or series) I'd like to know. Thanks

  5. Try this:

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  7. Nice to see an organized teardown. For those looking for a replacement power adapter, this should work. http://www.ebay.com/itm/9V-2A-AC-DC-Power-Supply-Replacement-Adapter-with-3-0mm-x-6-3mm-Tip-Center-/361490633905?hash=item542a8554b1:g:DC4AAOSwjXRXaHJJ

  8. If you want specs on the original adapter, this site works well.

    Note that THIS IS THE INCORRECT VOLTAGE! The correct voltage is 9V.


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