not the cheapest suppliers. You need the 8MHz version and Computer Express
(____ _____) have them at £135 + VAT – there may be cheaper sources around.
Installation of the chips on your GM888 board is easy – just lift out the 8088 and,
after bending the pins of the V20 against a hard surface to get them perpendicular
to the chip, insert with the U-shaped notch facing the LED. The 8087 goes in with
the same orientation. Do take care with the latter – it is a ceramic encapsulated
chip (it gets very hot) and a friend of mine broke one in half while attempting to
insert it in his PC. Note that the modification will (theoretically) invalidate Gemini’s
If you are contemplating carrying out this upgrade on your PC, don’t attempt it
unless you feel competent enough to locate the 8088 or 8086 without causing
mayhem inside the case. Check the type number of your processor and order the
appropriate replacement – it does no harm to have an 8MHz V20 in an IBM PC-XT
(4.77 MHz) although the 5MHz 8087 at £95 is a lot cheaper than the 8MHz.
version. Most people will extract the appropriate i.c. using a small, flat-bladed
screwdriver, rather than a chip-puller but some care is needed. Makers’ guarantees
are invalidated by the change.
A two-part article on these processors appeared in the American magazine
Micro/Systems Journal in the Nov/Dec 1985 and Jan/Feb 1986 issues (pages 32-43
and 32-36 respectively). The author is Stephen Davis, the article is “Turbocharge
your 8086/8088 computer” and it is full of interesting information of considerable
importance to anyone who has more than a passing interest in the topic. I have a
couple of copies of the article which are available on a first-come basis (with an A4,
20 pence SAE please).