Kenwood: S-meter acting funny

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Biggie_Z

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I have a Kenwood TS-430S HF tranceiver. When I got it the S-meter wasn't functioning at all. When I looked inside I saw a broken pot (VR3) on the IF board. I looked it up in the service manual and sure enough it was the S-meter adjustment pot. After replacing it, the S-meter functions, but when I turn down the rf gain, the needle goes to increases instead of decreases and shows +60 when the RF gain is down all the way. What could be the issue here? Any help is appreciated.
 

K9DAK

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That sounds like normal behavior in my experience with my Yaesu FT-847. I believe it's supposed to indicate where your minimum received signal threshold is. So as you described... if you turn the RF gain all the way down and your S-meter indicates +60, you'll only receive a signal that strong or greater.

Hope that helps (and my meager explanation is correct)!
 

robertmac

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If you RTFM it should explain it there. Mine does for the FT-450.
 

majoco

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That's quite normal. The "S" meter indicates the voltage on the AGC line. If there is no signal and the RF gain is up full, then the AGC line has no voltage on it and the "S" meter reads zero.With a strong signal, an AGC voltage is developed to reduce the gain and keep the audio level constant - as there is now an AGC voltage, the "S" meter reads something. So now if you turn the RF gain down, nothing happens to the AGC voltage or the strength of the signal until you reach the point where the RF gain starts to reduce the signal level and the "S" meter rises even more - and if you continue then the AGC voltage induced by the RF gain control completely kills the signal and the "S" meter reads S10 +60dB or something.
 
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