Hi Gents, some very good news. The Argonaut 2 is now functioning perfectly. The audio problem was down to a 3.3ohm resistor on the control board was almost OC, had the effect of lowering the 13.6v rail to the if/af board down to 10.5 volts., hence the distortion and low audio volume. Thanks to all that assisted with suggestions 73 Snowy G0HZE