The Kenwood TS-520 and TS-520S, work fine. 100 watts out. No issues. Up until a month or so ago I regularly used the TS-520 to check into the East Coast Amateur radio net on 40m. Just trimming down the shack to one HF radio on my desk.
The TS-820S worked fine up until about 5 months ago. It still puts out 100 watts but doesn't seem to "hear"...signals that are S7 on the 520 or 520S, barely move the meter on the 820S. The other issue with the 820S is, while removing the top cover, I broke the speaker wire. An easy fix, just haven't done it. Also, The digital counter does not sync with the dial. The dial is on frequency, but the 820S has what I understand is a common problem that the digital readout does not sync with the dial. I've read about a few fixes however have not tried any.
All operate off standard 120v AC, not 12v DC. Though, you could buy a DC converter plug on ebay to use in place of the 120v AC plug.
You are welcome to hook up to a dummy load or my antenna to demonstrate working as I explained above.
They are each in nice physical condition. Non-smoking environment.
I have mics for two of them. Each mic is interchangeable, all 4 pin.