[Kenwood] TS-820S and ALC issues

[Kenneth G. Gordon]

Recently I have been using my backup TS-820S on SSB for a bit. Normally, I use CW and 
PACTOR and have had no significant problems with it.

However, yesterday, I was operating for a bit in the Idaho QSO Party, and decided to try a bit 
of SSB.

I noticed immediately that, at first, it was difficult to get more than 50 watts PEP output, in 
either USB or LSB, no matter what setting of mic gain or tuning.

Suddenly, however, I could easily achieve the rated PEP of 180 to 200 watts, even with the 
mic gain at a very low level. I didn't think, at that time, to look at the ALC meter.

This morning I tried SSB on 20 meters again, and was back to barely 50 watts PEP output (I 
have a PEP-reading wattmeter) even with the mic gain up against the high stop. Reducing 
the mic gain even a little from full-on reduces the PEP power output.

I then looked at the ALC reading, and discovered that when keying the rig on without even 
speaking into the mic at all, or with the mic gain fully OFF, the ALC meter is pegged, and 
nothing I can do will let it fall back into the proper region.

About 30 minutes later, after not operating at all, the ALC meter is sitting just above the 
"safe" region of the meter. When keying the mic, the ALC meter rises a bit, and "sticks" 
there. Power output when adding audio input is still about 50 watts PEP.

This is saying to me that the ALC circuit is somehow intermittant, or intermittantly locked into 
full on, and is reducing the transmitter power output.

I find nothing in the service manual that addresses this issue, or even how to adjust the ALC.

Can anyone here help?

Ken W7EKB