Home > Previous Page >  EB Video Board
Archive Search  

EB Video Board

By Edwin Blink

  From the first moment I saw the 2nd edge connector on the Jupiter Ace I wondered what it was used for and I didn't know until I read the ETI magazine article about the colour interface and learned what signals where on that connector. As soon as I read there was a video signal on it, the idea for a monitor adapter was born instantaneously. The video signal on the connector is the same that is fed into the TV modulator so I thought that all that needed to be done was to take a edge connector, connect a some wires to it, a plug on the other end and hook it to a monitor.

  However After doing that I discovered that it did not work because the video signal was not strong enough to drive the monitor input. So amplification is needed. Because the Aces video signal is not that much different from the ZX81's, I decided to boost the video signal with a single transistor amplifier as I have seen in several ZX81 designs and this worked with out any problems.

  When you look at the schematic you see that I have used a transistor and a variable resistor. You could leave out the resistor and just use the transistor alone if you want. But I have added it to prevent the transistor from blowing when the output is shorted accidentally and It allows a little tweaking of the video signal.

  When you have a look at the pictures you see that I have put the RCA connector at the right side of the board. But I recommend to put it at the left side. The wiring will be easier this way. For the pin outs on the edge connector, check out the edge connector diagram. Good luck with making your own board.


The EB Video Board in its location on the Ace's Video edge connector.