dinsdag 18 december 2018

Philips G7000 - Videopac

 
My first game console was a Philips Videopac G7000. My father bought it, and I spend hours blasting spaceships, eating square 'dots' and playing tenpin bowling... I remember there were games I played so much that I could finish them with a perfect score every-time (games were not that complicated in those days). And, lets not forget, this computer actually started my programming career. Videopac cartridge nr. 9 turned this game console into truly programmable computer. Programming was limited to 100 bytes, output was a single line of 16 characters and you had to enter your commands in hexadecimal code. Or you could actually enter them in as 'assembler' text, but you could not list your program as such so it was easier to just enter the code .






I spent a lot of my savings on games and as far as I remember we had a box full of them in the end. Then, after not using it for a few years (since I got into PC gaming), we sold it.
But as with everything from this era, the nostalgia kicks in and I felt an urge to add one to my 8-bit collection. Fortunately more than a million were sold at the time so they are not rare and relatively easy to get.

I bought mine for €50, including 6 games which is not bad. The unit definitely looks used. One of the joystick knobs is missing and it has some dents and scratches, but not much more than the one we had 30 years ago.
The Dot Eaters site has a nice story on the Videopac or actually the Odyssey2 as it was known in
other countries. Though many were sold, it is not a hugely popular collectors item these days, and information on the internet is widely scattered with lot of websites that look like they were made in the nineties. There is a list of games on Wikipedia, but only few of them have an actual article or description.

As mentioned, the unit I got was definitely used, and showed some marks of that. So I cleaned it and the first thing I did was to add connectors for the joysticks. This series consoles came with the joysticks hardwired to the console, which is really annoying if you want to pack the system up. The weird thing is that the housing does contain the space for external connectors, they were just not installed, probably to save some money. So I just removed the two pieces of plastic that covered the connector holes and mounted two 9-pin D connectors.
There is a VideoPac forum, and one of the posts shows the wiring of the joystick in detail. The colours match the colours of the wires in the cable, so I just cut the cable and soldered it to pins 1 to 6 of the connector.

Next issue was the missing joystick knob. Which is not a big deal in these days of 3D printing so I designed and printed one that turned out remarkably nice. Its on Thingiverse now, so you can print one if you need it.
Then came the joystick itself. The Videopac joystick is a bit of a unique design, with 8 switches arranged in a circle which are activated by a disc that you tip to a side by means of a large spring.

The switches are just metal strips that you push down to touch another piece of metal on the PCB.
I set out to make a complete new base, now with 8 mini switches as shown here.
That did not really work. When I mounted the disc again and put the spring in place the disc just activated all buttons at once. Clearly the spacing was much more critical than anticipated, so I placed the switches on second board and put that underneath the first board.
Now only the buttons stick out, and this seems better. But it still did not work great. Now the problem was that the centre of some switches was not exactly under the edge of the disc. Since this is a rounded edge it sometimes just hit the side of the button and the switch would not fully close. So I ended up printing a new disc, slightly bigger than the original and with a flat ridge that covered all the switches.
And this works surprisingly well. After reassembling the joystick it works flawlessly, and I immediately used it to set my high score on Munchkin !




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