Hardware articles index > Crystal Clear Pictures from c't Magazine 1983.

  Below is an English translation for the article that was originally written in the German Magazine c't. Although we have try our best to translate it there may be to odd word of phrase that does not translate into English very well, so below is also an image of the German article which you can download.

  Quality of pictures on small PC is not good - can be improved by using the Video socket.

To allow the ZX 81 to recognize a monitor or TV set with Video socket a small extra switch, which can be easily installed on the circuit board, is needed.

extra wiring into both types the following applies:
Depending which monitor you are using you might leave R2. If the receiver of the monitor is very sensitive, a variable resistor as R2” should be used and find the best setting by trying problems with synchronisation can be solved by using the adjustments on the monitor (signed as VERT, HOLD, HOR, HOLD HOR, FREQU, or similar all works on the open monitor must be carried out with utmost care - some points are under high voltage.                  □
keep the pins. The connections next to the left edge of the circuit board Is for the video signal. After disconnecting this the signal for the extra wiring
can be taken from the circuit board. On the rear side of the ACE two wires appear, one to supply the modulator with +5V, the other to supply the video signal. For building in the
  It consists of a impedance changer on the exit of which the video signal is available with low resistance. The computer is supplying this signal to Pin 16 and IC1 (Sinclair Computer Logic) which is usually connected to the modulator entrance UK2.

  Looking at it from the front it is the left connection of the modulator - The signal can be taken from the connection on the main circuit board which is signed as UK2.

The modified ZX81                  The modified Jupiter Ace
  The Jupiter ACE is using the same modulator as the ZX81, whereas the same extra wiring can be used.

  To open the ACE the two pins in the middle of the plugs should be pushed carefully into the computer case. After removing the upper part of the case

Click to download the original German Page