Re: Audio Buzzing

WA6PXC Rich <sigma@...>
 

Hi Rich,
I have also had a buzzing noise in my audio.
I use a Nextion 5" screen. It was powered from the common LM 7805 5 volt supply
which is mounted to the radio chassis for a heat sink. I substituted an isolated 5 v supply
and the buzzing went away! To solve the problem, I placed a 1 watt 4.7 ohm resistor between the
13.8 volt supply and the input to the 7805, then placed a 470 uf 25 volt cap from the junction
of the 4.7 ohm resistor and the 7805 input to ground..Not a hint of buzzing now!

Kind Regards..
Rich WA6PXC

-----Original Message-----
From: Rich aka M7PEZ
Sent: Jan 27, 2019 9:27 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Audio Buzzing

Right... in the audio, there's a humming and a clicking.  They're two sounds.  

I do indeed have a Nextion screen with CEC Chris.  Unplugging the screen does indeed remove the humming noise.

Let's see if a battery eliminates the clicking.

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