Amstrad User Group

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The Amstrad Laptop computer ALT-386SX and ALT-286

The ALT-386SX dates from 1988 and is a laptop computer based on the Intel 80386SX (so without the mathematical coprocessor built-in) with a clock speed of 16 megahertz. There is version on the market that is almost identical to the 386SX but based on the Intel 80286 (AT) processor, with the type designation ALT 286. I obtained one during the HCC!dagen 2006 and will investigate it (to be continued). The facts and figures on this page only relate to the 386SX version, although these can also apply to the ALT-286. The computers look identical and use, at least, the same battery pack and share the User manual and even the Service manual (that we also have) which indicates that many parts can be exchanged between the two models. The 286 comes with a 20 megabytes hard disc and the 386SX with an 80 or a 170 megabytes hard disc.

Prolonged work with this computer in the literal sense (on top of your lap) seems impossible to me: the computer weighs around 7 kilos and makes an indestructible, somewhat bulky impression. In spite of the massive and bulky looks the ALT-386 is surprisingly fast. When compared to a Pentium III running on 1 gigahertz this 80386SX running on a clock speed of 16 megahertz is not performing bad at all... For a part this is due to the difference in software: the ALT is running Windows 3.11 that is a lot quicker than Windows 98SE as used on the Pentium. In addition the Pentium has a lot of peripheral equipment that requires a lot of initialising during start-up. But in addition to the faster boot by the ALT, regular work is also quite fast. The 80286 version will, naturally, be a bit slower.

A characteristic design feature of this laptop is the single eccentrically fitted hinge on the Liquid Crystal Display (LCD screen). Instead of in the middle, as you would expect, this is fitted to the extreme right of the base unit.

The LCD screen has another neat feature: using software you can set almost all screens in reverse video (exchanging background and foreground colours). But on the ALT you can do this with a button on the front of the hinge.

This should not be underestimated when working under changing light conditions: the photographs clearly demonstrate the striking effect of the settings. Besides this feature, the ALT also has the common contrast and brightness controls. The graphics action is performed by a card from the well known Cirrus Logic company. The memory size looks strange to me: 3,712 kilobytes. Not a multiple of 1,024 which is the logical number you would expect but it was confirmed by a number of test programs, so... The 386SX version normally comes with an 80 mb hard disc but this one has been upgraded to a 326 mb disc.

The picture on the left shows the ALT with the screen folded down and the carrying handle pulled out. The machine can be placed upright, in balance, with the handle upwards.

The picture on the right displays the spacious carrying bag from Amstrad with the large pockets for peripherals, manuals, floppy discs or working documents. This is my kind of carrying bag...

There is one more interesting feature, visible on top of the carrying belt.

Apart from the common shoulder belt (visible in the top of the photograph), the ALT bag has two carrying belts, shopping bag-style.

These belts can be connected using a soft leather strap with Velcro on the inside. This ergonomic feature provides for a comfortable carrying method, which is required indeed as the beast weighs in at 7 kilos!

The left photograph: the back of the laptop with the parallel Centronics printer port, two serial 9-pins ports (of which one is used for a mouse).

To the right of the serial mouse connector, a set of dip switches with the following functions:



    ALT DIP switch settings (Bank A):

  1. Sw1=Off, Sw2=On, Sw3=On 512K memory
  2. Sw1=On, Sw2=Off, Sw3=On 1MB memory (default)
  3. Sw1=Off, Sw2=On, Sw3=Off 2MB memory
  4. Sw1=On, Sw2=Off, Sw3=Off 4MB memory
  5. Sw4 (ALT386SX Only) - Page mode - ALWAYS On
  6. Sw5 - Wait states - ALWAYS Off
  7. Sw6 - 8/16MHz clock - Off = 16MHz
  8. Sw7 - Mono/Colour - On = Colour
  9. Sw8 - Enable/Disable serial - On = Enable
  10. Sw9 - (ALT386SX Only) - Pipeline - ALWAYS ON
  11. Sw10 - Drive B: - type II - ALWAYS OFF
  12. ALT DIP switch settings (Bank B) are as follows:

  13. Sw1 and Sw2 ON = Onboard VGA enabled
  14. Sw1 and Sw2 OFF = Onboard VGA disabled

Further to the right, invisible on the photograph above is a standard ISA expansion slot as well as a connection for an external VGA monitor. Even more further to the right is a connection for an external, AT-style, keyboard. The ALT comes with two utilities that can be loaded at:

To the right is a 1,44 megabyte 3.5" disc drive and a connector for another, external, disc drive using a Centronics style connector. A common defect with the ALT is a malfunctioning 3.5" disc drive.

And the Teac FS-235HF drive only has one cable: the power is supplied through (a few of) the ground connections of the data cable. Ideally for a portable, where space is always an issue.

But replacing a defective disc drive by a standard model is a problem because these all have two cables: a separate power connection and a data cable.When you use a standard 3.5" 1,44 HD drive you will need to cut the power leads from the data cable of the ALT. See the schedule on the left (you can enlarge the size of the picture).

To supply the replacement disc drive with power, you can use the wires cut from the original ALT connection. Or, alternatively, you can use the power supply of the ALT directly.

See the layout on the left side (you can enlarge the picture). This schedule can also serve a purpose when you want to connect a new, replacement, battery: you would need to make a new battery because the original batteries are no longer supplied.

This could be an expensive affair, when you put the job to one of those firms specialised in batteries. But, on the other hand, a new battery will be considerably lighter and more powerful (longer lasting) than the original battery with, by now, out-dated technology.

On the right you will find another scan from the technical service manual showing, again, the connection and wiring of the internal 3.5" disc drive.

Plus the wiring of the connector for the external disc drive, with the 36-pin Centronics-style connector shown in the photograph above.

This picture can be enlarged and displayed in it's proper proportions by saving it (use the right mouse cursor on the picture to bring up the menu containing Save Picture As).

Then use Word to insert and print the document or use a graphics viewer. You can use this procedure with the other two scanned diagrams on this page too.

None of these diagrams have been displayed in proportions: I will probably add some Java script code later to display them in their own window.

I have scanned the part of the user manual, dedicated to the ALT 286 and 386 in specific. Download ALT.PDF containing 66 pages (2.910 kilobytes).

Here is a part is the technical user manual, related to the VGA of the ALT. In low resolution, split in various parts and not (yet) edited or in PDF: still useful I guess:

altcont.jpg index of the manual and data (968 kilobytes).

altvga1.gif layout of the VGA-card, top (1,218 kilobytes).

altvga2.gif layout of the VGA-card, bottom (1,364 kilobytes).

altvga1t.jpg schema of the VGA-card, top part 1 (868 kilobytes).

altvga2t.jpg schema of the VGA-card, top part 2 (11,24 kilobytes).

altvga3t.jpg schema of the VGA-card, top part 3 (985 kilobytes).

altvga1l.jpg schema of the VGA-card, bottom part 1 (378 kilobytes).

altvga2l.jpg schema schema of the VGA-card, bottom part 2 (329 kilobytes).

altvga3l.jpg schema schema of the VGA-card, bottom part 3 (540 kilobytes).

Questions about the ALT-386SX and ALT-286 via the contact formQuestions about the ALT-386SX

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