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I bought an MFJ-9420 20 meter radio reciever and there seems to be an issue with the volume.

Radio works, i've heard people on 20 meters with a tuned dipole, the only thing is when i turn up the volume to hear better the S meter maxes out and I lose audio to a pulsating buzzing/humming noise that sounds like speaker overload. What is going on? My first thought was a grounding problem maybe with an op amp, but I don't know this radio well at all. I was hoping someone might know what is going on and how to fix it.

Posted by andre on

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langhi

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  • Expert
  • 104 Answers

It sound like your power supply is not providing enough output for the radio. Are you by chance using a wall wart for power? You need a dedicated 12 volt power supply, made by Astron, QJE, or Pyramid.

Posted on Oct 03, 2019

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lars ahlsen

  • 47 Answers

SOURCE: 75-822 cb that has extremely low audio output

Hello..if you can try to connect a external speaker or phones..if the volume is ok..than i think it is time to replace your internal speaker..pse tll me....good luck...Ron

Posted on Mar 15, 2008

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Inno Laur

  • 93 Answers

SOURCE: Technics SA-DA10 jumps into overload after 10 minutes

Have you tried connecting speakers? What was the result?

Yes, when you turn the volume up on these amps (or when the output gets past a certain level) the cooling fan should automatically come on.

Posted on Oct 14, 2008

Anonymous

  • 1 Answer

SOURCE: Vizio 42'' HDTV flatscreen

The TV usually hums when the backlight setting is too low. So turning it up should get rid of the problem. To do this please follow these instructions:

1. Turn the TV on.
2. Press the Menu button on the remote, located right below the channel changing button.
3. Press the down direction button, located at the middle of the remote. Press that button until the backlight is highlighted.
4. Press the right direction button until the backlight is at 100.
5. Press the OK button and then the Exit button until you get back to your picture.

Posted on Feb 21, 2009

Anonymous

  • 655 Answers

SOURCE: Humming sound to speakers from amplifier

Hello,

It sounds like you may have a ground loop issue. I'd start by checking all the power and ground connections. Then disconnect the RCA wires from the amplifier. If the hum goes away then you should try grounding the stereo to a better grounding point, the factory grounds are usually not very good at all. Then try it again, if it is still there try replacing the RCA"s.

If the hum is still there after you've redone the connections and replaced the RCA's, you may need to install a ground loop isolator.
Both www.crutchfield.com and www.sonicelectronix.com sell good ones.

Hope this helps

Posted on Mar 29, 2009

Anonymous

  • 63 Answers

SOURCE: LOUD BUZZING/HUMMING SOUND- CAN HEAR OVER AUDIO

have someone check speaker ground to the TV chassis. Your speakers are picking up reverb from the Video Signal.

Posted on Aug 19, 2009

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