Here is what I know. Bill the owner of TT has had my TT since November 2011 for failure evaluation. So I am out $250 !
I was going to repair the thing myself. He insisted I send it to him.
73 Tony N5UD
That is why I use a rocker switch and my ear to tune my Scorpion. I get close every time and just have to bump up or down and the swr is good. YMMV
I went back to manual tune ever since I boxed up the TT in 2011, and sent it to Bill.
Mine also has a switched voltage dropping resistor so I can go to 1/2 half speed on the motor.