1. Outlook of Dubna 48K

2. Mainboard

3. CPU and ROM

4. RAM

Dubna 48K is a Soviet clone of ZX Spectrum home computer. It was based on an analogue of Zilog Z80 microprocessor. Its name comes from Dubna, a town near Moscow where it was produced, and "48K" stands for 48 kilobytes of RAM. The Union of Soviet Socialist Republics (USSR) (Russian: (СССР)   listen?; tr. ... The Sinclair ZX Spectrum was a small home computer released in the United Kingdom in 1982 by Sinclair Research. ... The home computer is a consumer-friendly word for the second generation of microcomputers (the technical term that was previously used), entering the market in 1977 and becoming common during the 1980s. ... The Zilog Z80 is an 8-bit microprocessor designed and manufactured by Zilog from 1976 onwards. ... Microprocessors, including an Intel 80486DX2 and an Intel 80386 A microprocessor (abbreviated as µP or uP) is an electronic computer central processing unit (CPU) made from miniaturized transistors and other circuit elements on a single semiconductor integrated circuit (IC) (aka microchip or just chip). ... Dubna is a small city located in central Russia, in the Taldomsky district of Moscow Oblast, approximately 125 km north of Moscow, on the banks of the Volga river. ... Saint Basils Cathedral and Spasskaya Tower of Moscow Kremlin at Red Square. ... A kilobyte (derived from the SI prefix kilo-) is a unit of information or computer storage equal to either 1024 or 1000 bytes. ... This article is about the animal, sheep; for other meanings of Sheep, see Sheep (disambiguation). ...

According to the manual, this computer was intended for:

• Studying principles of work with PC
• Different kinds of calculations
• "Intellectual games"

By the time this computer was released (1991), there were already much more powerful x86 CPUs and commercially available advanced operating systems, such as UNIX, DOS and Windows. Dubna 48K had only built-in BASIC interpreter, and loaded its programs from a cassette recorder, so evidently, it couldn't run any of modern operating systems, and as such, wasn't suitable for "studying principles of work with PC". However, Dubna 48K and many other Z80 clones, hopelessly outdated by that time, were largely introduced in high schools of Soviet Union. According to a contemporary who studied at a school in Chelyabinsk in 80s, they used wooden plates with keyboard drawn on them, as the schools lacked PCs greatly for the lessons of Computer Science. So even these outdated computers were considered as a great boon. x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ... Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... The acronym DOS stands for disk operating system, an operating system component for computers that provides the abstraction of a file system resident on hard disk or floppy disk secondary storage. ... Windows may refer to: the architectural feature (for seeing out of buildings); see window a concept in computer graphical user interfaces; see window (computing) the computer operating system, Microsoft Windows the 1981 movie, Windows This is a disambiguation page — a navigational aid which lists other pages that might otherwise share... The word basic may refer to one of several articles in Wikipedia: Basic English BASIC programming language Basic (chemistry), the opposite to acidic, reacting with acids to form salts. ... An interpreter is a computer program that executes other programs. ... Chelyabinsk (Russian Челя́бинск; also transliterated as Cheljabinsk, Čeljabinsk, and Čelyabinsk) is a Russian city just to the east of the Ural Mountains. ... Centuries: 1st century BC - 1st century - 2nd century Decades: 30s - 40s - 50s - 60s - 70s - 80s - 90s - 100s - 110s - 120s - 130s 80 81 82 83 84 85 86 87 88 89 Note: Sometimes 80s is used as shorthand for the 1980s, the 1880s, or other such decades in different centuries. ...

Moreover, most of the games for Z80 were already available for Nintendo's 8-bit game console, marketed in Russia under the brand "Dandy", and it was much cheaper, more reliable and easier way of playing games, so it became clear that Dubna 48K wasn't in much demand for home users.

Included items

Dubna 48K was shipped with the following units:

• Main unit ("data processing unit", as stated on its back side), with mainboard and built-in keyboard
• External power unit
• Video adapter for connecting the computer to the TV set
• BASIC programming manual
• Reference book, including complete schematic circuit

Additionally, there were some optional items:

• Joystick
• 32cm (12") colour monitor

The computer could also connect to a ZX Microdrive, but such device was never included. The ZX Microdrive was a tape-loop storage system from the 1980s, used in Sinclair Researchs ZX Spectrum and Sinclair QL home computers. ...

Technical Details

• CPU: 1.875 MHz, 8-bit
• RAM: 48 Kb (in 16 KR565-series chips, see picture 4)
• ROM: 16 Kb (picture 3, two white chips in the middle)
• Resolution: 256x175 pixels, or 22 rows of 32 characters each
• Number of colours: 8
• RS-232 port
• Power unit: 5V, 1.7 A
• Dimensions of main unit: 52x320x255

This CPU uses numerous pins to connect to the motherboard. ... A megahertz (MHz) is one million (106) hertz, a measure of frequency. ... This article is about the animal, sheep; for other meanings of Sheep, see Sheep (disambiguation). ... Rom is also the name of a toy and comic book character Rom (Spaceknight). ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ...

Other facts

• Dubna 48K has its case made of steel, while other Spectrum clones had plastic cases.
• There are people who buy used PCs like Dubna 48K. The reason for this is that these computers contain little amounts of gold and silver. For example, Dubna 48K contains (according to the manual) 1g of gold, 3g of silver and 0.1g of platinum.
• Due to lack of some chip, it could be replaced by several others. How to do this is described in the reference book shipped with the computer. For example, in the upper part of picture 4 you can see a small board with 3 chips installed in place of a single K555IR9.
• Unlike Dubna 48K, most Z80 computers were assembled at home by amateurs, inspired by numerous articles in the Radio magazine. Programs for these computers, usually taking many pages (in binary codes) and BASIC programs were also printed in this magazine and had to be typed in manually.

See also

• List of ZX Spectrum clones

The following is a list of clones of Sinclair Researchs ZX Spectrum home computer: ATM AZX-Monstrum Baltica Best III Bi Am ZX-Spectrum 48/64 Bi Am ZX-Spectrum 128 Cobra CIP-03 Composite Delta Delta S-128 Didaktik Gamma Didaktik Kompakt Didaktik M Digra Ella Ra Elwro...