Nascom News­let­ter

near the mains input plug and directly in front of the tuner. On the TX10 it is an the vertical panel to the right of the tuner.

Syncs from TP8 on the AVC should be wired (via an isolating capacitor) to pin 8 of the socket that the i.f. module plugs into (marked as PL4).

The Red, Green and Blue outputs should be wired, via isolating capacitors) to PL18 pins 4, 3 and 2 respectively. A supply of 5 volts should be taken from the computer via a 470R resistor and wired to PL18 pin 6 (pin 5 on the TX10). This will supply about 3 volts to the decoder IC and internally switch it from video from the i.f. panel to the data inputs. Pin 1 of PL18 is earth. These connections are shown in the diagram below.

For the few that may need their TX set to watch television programmes, it could be arranged to switch the AVC sync and the i.f. video output at PL4 with a CMOS switch operated by the 5 volt supply from the Nascom and, together with this supply also switching the decoder IC between video input and data inputs, an automatic changeover from TV to computer when the computer was plugged in could easily be achieved.

A very important point – before any work of this type is done, the TV set must be isolated from the mains. This not only protects you but also the computer. A suitable torroidial isolating transformer which is small enough to fit inside any model can be obtained from ILP Electronics, ______ ____ _____, _____ _____, Canterbury, Kent ___ ___. (type number 32050).

PL18 connectors shown for TX9