The Radio-86RK was the second DIY computer featured in Radio magazine, in an edition published in June 1986. It was the successor and more popular than the Micro-80 because it was much simpler with just 29 Integrated circuits, (the Micro 80 had 200).

It had a clone of an i8080 main processor running at 1.78 MHz. The name seems to be derived from the name of the magazine and the year. RK may be a short form of Do It Yourself Kit.

Many factories started production of home computers based on this design (such as the Apogey BK-01, Microsha, Krista, Partner 01.01, and the Spektr-001). These computers had limited compatibility with the original software, although their schematics were very close to the original. the whole computer family could be called "RK-86" compatible. A lot of clones were built, some even on an industrial scale.

It may be that the 8-bit CPU K580VM80 used for the Radio-86 is a clone of Intel 8080A, other specs include having 16/32 Kb RAM, 4Kb ROM, 25x80 monochrome display (TV) and used tape recorders as the I/O. Based on the Radio-RK schematic, the following PCs were industry produced: Microsha, Krista, Electronica KR01…04, with a insignificant modification in electric scheme and BIOS. The additional adapters designed in 1987 – 1992 allowed the machine to produce sound, add colour display, attach Floppy Disk Drive support, and attach ROM modules.

The computer was not initially produced commercially. For the assembly of the computer required anyone wanting to build it to acquire the necessary chips, and to produce two printed circuit boards and then mount the components. Furthermore, then it was necessary to write firmware into two chip erasable ROM , and make a power supply unit, keyboard and computer case. The computer used a monitor with video in, or could use a modified television set.

The chips to build the Micro 80 and the Radio-86K were in very short supply, so completing the machine was difficult. Especially hard to get hold of was the video chip (KR580VG75) tending to only be available in Moscow or other large cities. This chip could be replaced, but at the cost of having to fit another 19 chips onto a separate board.

After being inundated by readers of the magazine unable to finish their machines, the editor of Radio, went to some of Russia's tech companies with a view to start producing kits of the machine. By the end of the 1980s, cases, keyboards and motherboards were being made.

All Very kindly donated by Alexander Demin. His blog and details of his projects can be seen here.

Although the design was from 1986, this machine was constructed in 1989.

An emulator from Alexander Demin is on line so that you can play with it, it is in Russian but you can soon sort it out at http://rk86.ru/ and a catalog of programs for Radio-86RK can be found at http://rk86.ru/catalog/ 

Manufacturer: Home Built
Date: 1989

This exhibit has a reference ID of CH32376. Please quote this reference ID in any communication with the Centre for Computing History.

Click on the Image(s) For Detail

	Articles