General Description:
The VideoSport MK2 was sold in 1974 or early 1975 by Henry's, a British retailer
of televison and Hi-Fi equipment. It is one of the earliest European PONG systems
and uses analog circuits. It was still available at Henry's in early 1977.
Customers could either buy it in the stores, or have it sent by mail. The box of
our specimen was shipped to its original owner in January 1977 and shows a hand-written 2819
in very big digits. If this is a serial number, then less than 3000 specimens
would have sold in two years, which is very low. In this case, it is possible
that only a few thousands of units were built. Seeing that sort of model being
still sold in stores in 1977 was common back in the 1970s. There was no need to replace one model
when a more advanced one appeared on the market. Although many advanced models
were available, earlier ones were still proposed at a lower price (hence the
discount between the two advertisements below and our boxed unit,
originally purchased for £20.20).
The hand assembled electronic circuit board is very basic: it has
only two
small basic TTL integrated circuits (NAND logic gates). The rest is made of discrete
components. This is a typical design for an analog system released in small
amount. The electronic circuit of this system is the simplest one after the
Magnavox Odyssey. The system is only powered by the mains
(no batteries). Curiously, the bottom sides of the case and hand controls are glued rather than screwed,
making it difficult to open the main unit without damaging the borders.
Two versions are known to exist: the earlier one with
gold letters, and the later one without gold letters. The absence of gold
letters in the latter could have been decided to reduce the production cost of
the cases. The push-buttons could be black,
yellow or white as these systems were mostly hand assembled with parts purchased "on
the fly", as opposed to systems made by bigger companies who ordered the whole
stock of electronic parts, which were machine assembled.
The system plays three games without any difficulty level, although it
would have been easy to adjust the ball motion, paddle size, etc. Such settings
were common with analog systems.
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The first game is obviously TENNIS (PONG). Each player uses two knobs to move his paddle (one to move horizontally and one to move vertically), and one push-button to serve the ball. There are no on-screen scoring and no sound effects, which is a common thing with early analog systems. However, the picture quality is very good compared to the type of components used. Most other analog systems used more integrated circuits to provide a better video signal. With only two chips, this system still provides a very good picture. |
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The second game is FOOTBALL, which is quite rare on analog systems. It plays just like TENNIS, but with two lines with a hole on their middle to act as goals. Because this game can be played with only two paddles, there is no football team, so each player acts as a goal for the other. This game should have been named GOAL instead... |
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The third game is HOLE IN THE WALL, another Ball and Paddle variant without central line, where one player is an inverted paddle so as to display as a vertical line with a hole instead of the paddle. Alghough this game is very common with analog systems, this one is played differently. First, the hole is located on the left of the screen, instead of the right like most other analog systems. Second, the hole is controlled by both players instead of one: not only the hole faces the paddle when the second player (right) moves vertically, but the first player (left) can only move the hole horizontally. Thus, each player moves the hole in one direction. This is a very strange version of this game, which has a major drawback due to the 2-player control of the hole: it is not possible to play other variants like SQUAH (where the hole is located so high that it doesn't display), BASKETBALL (where the hole is located on the top of the screen), and MOUSE HOLE (where the hole is located on the bottom of the screen)... |
Electronic circuit:
The electronic circuit is very simple and is a good example to understand how
these analog game systems work.
The first strange detail is the use of the two TTL 7400 chips (NAND gates). Most analog systems
used these gates wired in "NOT mode". In this mode, their two input lines are
connected together so that they become logic inverters. A simple flip-flop can be made with two inverters, and one simple graphic
object like a ball or a paddle can be made with two flip-flops. One could think that the
two chips are used as flip-flops, but they are not. They are used for other
purposes such as collision or
bounce management.
The generation of the ball and paddle graphics are entirely made with discrete components:
transistors, resistors, capacitors, etc. The system has nine flip-flops: six are used to
display the two paddles and the ball (two per object), one is used to draw the central line
of the TENNIS game, and the remaining generate the vertical lines of the FOOTBALL game.
It is possible that the inverted player of the HOLE game be generated by two flip-flops
and one NAND gate wired in inverter so that the NAND gate transforms the paddle in a line with a hole.
First version of the system with its two controllers and gold lettering.
Left: one controller. Right: game selector on the unit.
Later version of the system without gold letters.
Earlier box and manual. Click the pictures for larger view.
Shipping box of our 1977 specimen with its later (xerox) manual.
Click the pictures for larger view.
Inside of the system: only two integrated circuits and discrete components.
Note the eight potentiometers used to adjust the size of the ball, players, etc.,
which are required in analog circuits. The flip-flops are located on the central line.
The two transistors of each flip-flop are those small
gray rectangles.
Left:
Early 1975 advertisement in Elektor showing the Videosport MK2 at £34.72 + VAT.
Right: advertisement in Elektor in May 1976 discounting the game at £29.50 + VAT.
The system was discounted at £20.20 later in 1976 or early in 1977.
