Bush DAC90A with FM.

[Geordie McBoyne]

It might be a good idea to insert a buffer stage between the audio output from the FM module and wavechange switch. With the module output disconnected and the free end of the audio lead connected to an oscilloscope it was found a pulse of 2volts or thereabouts appeared when the wavechange switch was turned between LW and FM. In the DAC90A the bottom end of the volume control is returned to the cathode of the UBC41 audio amplifier. Much better to return the volume control earthy end to chassis and fit cathode bias components to V3, the UBC41.
One of the modifications suggested by Kalee20?

Geordie Boyne.