The problem with the PTT wiring has been really bothering me. One of the cats managed to wake me up Sunday night, and I laid there in bed for three hours stewing on the problem. Pondering the various possible causes of the problem, deciding how I could rule out each possibility, and planning the easiest way to fix each possible problem. As a result, I didn't get near enough sleep, and was too tired and depressed to attack the problem Monday evening.

I slept well last night, and this evening I planned to methodically attack the problem. I figured I would probably have to disassemble the stick grip, so I put the cockpit floor and front seat back in, as I needed a place to sit while I worked. Then I took another close look at the wiring. After studying it a while, I noted a black wire that was routed in the main wire bundle, but wasn't connected to anything. I followed it back, and it went to the wire bundle that came from the stick grip. I connected the ohmmeter to it, and the other wire that was supposed to come from the PTT switch. I pressed the PTT switch on the stick grip, and the ohmmeter showed that the circuit had closed. Bingo!

What a sense of relief! My wiring is OK after all! I just needed to find the right wire. No tearing the stick grip apart and then trying to get it back together again. It was a very difficult job getting it assembled when working on the work bench, and I could rotate it to any position I wanted. It would be an extremely difficult job trying to do it with the stick in the aircraft. And I can't remove the stick without either tearing all the wiring out, or cutting the wiring harness and splicing it later.

Now that I knew the PTT switch worked, I took some jumpers and connected it up to the PTT wire in the audio panel harness. I was able to determine that each Com radio transmits upon command. Now I need to get Jim Manton over to transmit while I listen on the VHF scanner.