Kenwood TH-G71A Volume Control Problem

Kenwood TH-G71A Volume Control Problem

Post by J. Richard Hann » Mon, 25 Mar 2002 11:53:02

My Kenwood TH-G71A Handheld over the past several months has developed a
problem with it's volume control operation, while the volume level is set
fairly low, all of a sudden the volume from the speaker will increase to a
much higher level without touching the control.  At this point as you turn
the volume control down further has no effect on the volume level setting,
but as you move the volume knob past it's 12 o'clock position the speaker
volume actually increases.

This problem would come and go and sometimes turning the radio off and
removing the battery pack and then reinstalling it and turning the radio
back on resolved the issue for days.  I have most recently tried reseting
the radio on power up and it had no effect.

The radios operation seems fine except for it  "possessed" volume control
operation.

Has anyone else observed this phenomena on their TH-G71A, and if so what
corrected it?

Thanks, Rich WA8NPR

 
 
 

Kenwood TH-G71A Volume Control Problem

Post by Bob M » Tue, 26 Mar 2002 05:09:28


No experience, however from the symptom and the fact that the first half of
the volume control has no effect, I'd suggest either a bad volume control
(inside) or a bad connection on the CCW (low volume) end of the control to
ground. Often the radio will have a small value fixed resistor at this end
going to ground, so when the pot is set to its minimum level, you will still
get some audio. This resistor, or the connections to it, could be
intermittent. Once the low end of the pot no longer goes to ground, it just
acts like a variable resistor in series with the high impedance audio, and
you get no control of it.

Most likely the resistor will be a surface mount component and very
difficult to find without a proper service manual and a magnifying lens.

If, unfortunately, the volume control operates some other electronic
attenuator, rather than just simply controlling the audio level itself, then
the attenuating component(s) could be at fault. This would most likely be
the case if the radio is so heavily microcontrolled that some sort of remote
volume control (i.e. without turning the knob) is possible.

Hope this helps.
Bob M. WA1MIK
======


Quote:> My Kenwood TH-G71A Handheld over the past several months has developed a
> problem with it's volume control operation, while the volume level is set
> fairly low, all of a sudden the volume from the speaker will increase to a
> much higher level without touching the control.  At this point as you turn
> the volume control down further has no effect on the volume level setting,
> but as you move the volume knob past it's 12 o'clock position the speaker
> volume actually increases.

> This problem would come and go and sometimes turning the radio off and
> removing the battery pack and then reinstalling it and turning the radio
> back on resolved the issue for days.  I have most recently tried reseting
> the radio on power up and it had no effect.

> The radios operation seems fine except for it  "possessed" volume control
> operation.

> Has anyone else observed this phenomena on their TH-G71A, and if so what
> corrected it?

> Thanks, Rich WA8NPR