Amstrad User Group

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The Amstrad Personal Computer PC 1512 and 1640.

The PC 1512 and 1640 are closely related: the first with 512 kilobytes and the latter with 640 kilobytes of memory and better graphics. Both machines are XT's based on an Intel 8086-II processor running on 8 megahertz. IBM compatibles that distinguish themselves from their contemporaries (1986) by their low sale price.

Both models were amongst the first affordable PC's that were manufactured on a large scale (a speciality of Amstrad). The machines have a high percentage of plastic but do not look cheap or fragile nevertheless. The American version of the PC 1640 is named PC 6400 (for reasons unknown to me).

The 1512 and 1640 come in different versions, first of all the SD (Single Drive) and DD (Double Drive) versions with one or two 5.25" floppy disc drives. The model shown in the photograph had it's 5.25" drive B replaced by a 720kb 3.5" disc drive. Other combinations of disc drives are not possible or useful.

This 1512, however, also has a Miniscribe 20 megabytes hard disk on board and was therefore designated HD. The whole series could be supplied with a variety of peripherals including monochrome or colour monitors, and could be upgraded later. This PC 1512, for instance, has received a memory upgrade and now features 640 kilobytes of memory - a task that can be done relatively easy as a do-it-yourself project.

Being PC/XT compatibles all models come with an 86-keys keyboard. This keyboard can be tilted by the foldable legs on both sides on the front of the keyboard. It has a fairly good operation and is not bad to work with.

The joystick and mouse ports are of the older 9-pins variety as used by Amstrad in their home computers too (the CPC). The mouse port is located to the left of the computer (see further on) and the port for the joystick to the left of the keyboard. A strange place to connect a mouse but one also found on some of the CPC computers.

A typical mouse with two-buttons (that handles well) is supplied with all machines: early for an XT-compatible but this was essential for the operation of the GEM system that came with the machines too.

There is a battery compartment in the system housing, just below the place where the monitor is to be placed. Contrary to other PC's, this location can be accessed without opening the system unit. This is the first (but not the only) computer where Amstrad introduced this location. These batteries only function to back-up the system clock of the computer, not to store for instance hard disc parameters in the BIOS (as introduced with the 2386). You can, however, easily restore the date and time should the battery be removed or become empty, using the DATE command in DOS.

These PC/XT hard disks came with a matching controller and expansion card so that the parameters for the hard disk did not have to reside in the BIOS of the computer - it was already in the ROM of the controller.

The computers each have three 8-bits ISA expansion slots (full length). The system unit has, as with the later models (the PC 2386 amongst them), a characteristic design which is typical for Amstrad. The expansion slots are located in the back of the machine and can be accessed both from the top side as well as from the right side. The lid can be removed from the top while you can also remove a sliding panel from the right side. This allows you to fit expansion cards that have an external use and require connections through the system unit.

On the left side we find the usual connections (although the keyboard and the back of the system unit also house connectors). The left port is for the mouse, the middle for the keyboard. The control on the right side is a volume control to control the system beep. The machine does not feature sound in any form, unless you want to count the noisy hard disc as such.

The system unit does not have a cooling fan, which resulted in quite a hype that these devices really should need such fans. In fact they do not need it but, forced by reviews in the press and distrustful customers, Amstrad later did build in (completely unnecessary) cooling fans in the PC's.

The last two communication ports, a parallel Centronics and a 25-pins serial RS232 port, are located on the back of the system unit of the computer.

The PC 1512 usually came with a monochrome Hercules screen but also supports Colour Graphics Adapter (CGA) monitors. The one in the photograph is a CGA colour monitor indeed.

The PC 1640 can deal with Enhanced Graphics Adapter (EGA) display and the setting scan be changed with dip switches. A rather nasty feature is the fact that the power supply has been located inside the monitor. That means that, when you replace the monitor, you will also have to find a solution to the issue of the power supply. A standard monitor will, of course, not have a power supply that can supply the system unit with power. Fortunately, the computer can be powered from the outside: a cable from the system unit leads to the monitor (as can be found on other computers too). The photograph shows the left connector, but the current goes into the "other direction" (that is: if you could speak of that with ac-voltage).

One of the strong selling points of this series is the large collection of software. Besides DR Dos (Digital Research DOS, a clone of MS Dos, just like the original MS Dos was cloned from DR's CP/M: this happens all over the computer industry) the machines came with GEM, a GUI (graphical user interface). It is amusing to see how this system (also from DR) tried to score points over Apple Macintosh in terms of user friendliness.

At the time MicroSoft Windows was not a serious alternative but DR GEM never broke through. Besides the fact the that battle had not been decided back then: playing around with GEM is rather funny. Although it does not offer the features that Windows or Apple's SystemX do, it is stable and does offer a true graphics user interface with the computer. This GEM was the main reason that a mouse was supplied with the computer. MS Dos, version 3.20, was supplied too so the user has a wide choice.

Nowadays the serviceability of the PC 1512 and 1640 is restricted to a few simple (Basic) games and light tasks like for instance word processing (WordPerfect 5.1 for example - provided you can store the software somewhere, you need at least a 720 kilobytes disc to store WP 5.1, still excluding dictionaries). There is a utility to fix the millennium problems on a 1512 but it can only be used with a newer version of MS Dos (not the version that came with the machine). The system discs and a driver program for the mouse can be downloaded from Amstrad's Home Page (the unofficial pages by Cliff Lawson - opens in a new window).

The computer shown on this page suffers from the exchange of the 5.25" disc drive by a 3.5" disc drive: because of that the PC will no longer boot from the 5.25" system discs. I will exchange the drives again, when I can find the time, so that DR Dos and GEM can boot again: the machine can now only boot from the hard disc using MS Dos. To be continued.

Questions about the PC 1512 and the 1640 via the contact formQuestions about the PC 1512 and 1640

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