[Kenwood] TS-820S and ALC - more-2

[Kenneth G. Gordon]

On 11 Mar 2012 at 13:32, Kenneth G. Gordon wrote:

> > Don't adjust anything. Clean the relay in the middle of the bottom.
> > Business card and contact cleaner ONLY. Nothing abrasive.
> > 
> > Clif Holland KA5IPF
> 
> Thanks, Clif. That was going to be my first step, since that is about all I can 
> do at this point... 

OK. I removed and carefully cleaned the relay with a folded piece of typewriter paper. 
Removed some black ick between some of the contacts. Then I used a SMALL amount of 
DeOxit, and then a SMALL amount of ProGold afterwards by wetting another piece of folded 
paper and working it between the contacts.

Replaced the relay, and the cover.

When first turning on the rig and keying the mic with no audio, ALC still pegs over against the 
right stop. Waiting a few minutes, then keying the mic, the ALC has slowly dropped back until 
it is just at the top edge of the "safe" zone.

Another set of clues:

With mic gain set at 2, rig loaded up to 225 mA input on 20 meters into a dummy load, 14260 
KHz. USB , when first keying the mic with no audio input, ALC pegs to the right. Continuously 
keying the mic on and off with no audio input, the ALC drops back in steps after each 
"keying" until it reads near the bottom (left) end of the scale.

Keying the mic, then speaking into it, instantly pegs the ALC reading even if I have the mic 
gain raised only just enough to give me an indication on the plate meter when speaking.. 

If I then hold the mic keyed, the ALC reading VERY VERY slowly drops back steadily. 
Although the meter switch is still set to ALC, using the mA scale to get a better idea of how 
slowly, it drops back 10 mA (on division) in 45 seconds. After 15 minutes, it rests at the 
bottom of the scale.

It seems to me that I have an open resistor, cold-solder joint, bad capacitor, or bad diode 
somewhere in the ALC circuit or related.

Now what? Any suggestions?

Ken W7EKB