Good morning,

The amplifier is tuning a radio station. The microphone and the amplifier was both repaired by an electrician; but to no avail, it keeps catching station.

Please what might be the issue(s)?

Thanks,
Babangida.

 

Usually, it is picked up in the microphone cable and demodulated by a diode or transistor in the input amplifier.
Is the cable screened? Is it a balanced line input?

 

Usually, it is picked up in the microphone cable and demodulated by a diode or transistor in the input amplifier.
Is the cable screened? Is it a balanced line input?

Yes, it was screened. A new microphone was even bought, still.

 

Failed or inadequate decoupling of the power supply might allow almost any part of the circuit to be affected by interference?