RE: Airtronics Servos
Well, actually, you can't just switch the power wires and use the old style servos. The plugs won't fit in the HiTec/JR common extension or receiver. The three ribs on the bottom that won't allow it to plug into the extension or the receiver.
However, if you get an adapter/converter extension for the old style servo connector, you just plug it into the old style Airtronics end, and the other end is a JR/HiTec type with the correct wiring.
I made some of my own, and still have them. I think they're on old Airtronics chargers, so I can charge idle planes with the old Airtronics charger.
Good luck,
Dave Olson