kenwood tk-880

Hi all -- relative newbie here, please forgive any ignorance. I got my hands on a beat up TK-880-1. I have another of these radios and I love it for GMRS. This one, though, seems to have had a tough life. What I assume is the reverse polarity protection diode is burnt to a crisp. But the radio...

I am using the KPG-49D for Windows for programming, and I key up on the radio on either channels 1 or 2 in group 1 it will go to channel 3 to transmit. Can anyone tell me why, or point me in the right direction to getting it so I can transmit on channels 1 and 2?