[rfeenstra]

So I pulled my 70 out and, with a flashlight, tried to see what you are looking at. Mine has the strap as well only the bottom side is riveted to the the chassis. that rivet is what is holding the insulator in place. I can't tell on your photo if the rivet is missing or if it is discolored and just looks like it is missing. that end of the strap should be connected to chassis ground through the rivet. The end under the screw should be isolated from the screw that connects to the stationary portion of the tuning cap. On mine, the wire is connected to the other screw - probably makes no difference as long as the wire has connection to the stationary part of the cap. The strap is then acting as a low value capacitor between chassis ground and the stationary part of the tuning cap.