Hi, I'm having an intermittent problem with the AGC on a Kenwood TS-180S
that I picked up on the Internet a week ago. The problem is this: most
times the S-Meter is very insensitive to signals, and the AGC switch does
not work. Also, the AF Gain control does not increase the volume very high,
and you have to turn it all the way up to get any volume out of the speaker.
Then, all of a sudden, the AF gain will get very loud, and the AGC switch
will start to have an effect (fast/slow/off), and the S-Meter show true
signal levels.

I was hoping maybe someone could offer a suggestion as to what might be
occurring.

Thank you

Lee KI6AZS

Hi Lee

So it sounds like the AGC loop is broken somewhere. The S meter is
pretty well always derived from the AGC voltage. Since you have low AF
gain this also reinforces the idea.

The RF gain control is often also plugged into the AGC loop. Have a look
for mechanical damage, slide/turn the pot back and forth a few times,
tap the chassis with a non conductive rod, flex the PCB's etc. Sounds
like a dry point to me..

Cheers Bob VK2YQA


Rockinghorse Winner wrote:

I was hoping maybe someone could offer a suggestion as to what might be
occurring.

Thank you

Lee KI6AZS

Bob Bob wrote:
Hi Lee

So it sounds like the AGC loop is broken somewhere. The S meter is
pretty well always derived from the AGC voltage. Since you have low AF
gain this also reinforces the idea.

The RF gain control is often also plugged into the AGC loop. Have a look
for mechanical damage, slide/turn the pot back and forth a few times,
tap the chassis with a non conductive rod, flex the PCB's etc. Sounds
like a dry point to me..

Cheers Bob VK2YQA



Thank's for the suggestion, Bob. Yes, I think I'm going to bring it
down to Kenwood service, which is about an hour's drive from my house.
I really like the rig, otherwise. It has excellent audio, and the AGC
doesn't seem to be affecting how many signals I can hear, just how loud
they are in the speaker. I.e., I can compensate somewhat by turning
the AF gain way up. It doesn't sound like a real complicated fix,
probably as you say, a cold solder joint or failing PCB component.

73

Lee KI6AZS