Today, I found the problem. It was in the PTT switch where a wire was pinched due to a screw that was holding the two halves of the stick grip together. Everything tested ok. I replaced everything, and tested each time I buttoned something up. Everything now works. It will be interesting to see if my trim light LED indicator was sensitive to the radio ground.
Finally, I removed the #1 valve cover, but in the process of trying to stop the leak, we had tightened the bottom screw too tight and it snapped coming out. So, now I have to remove a partial screw from the head. We'll try an extractor tomorrow. Hopefully it was the pressure of the head and not the threaded body that was working against me.
