I am a fairly new owner of a 1973 911E and I'm having an ignition problem. When I insert my key I can turn the key far enough for the radio and headlights to go on but no further. I can't get the car to start because I can't physically turn the key to spark it up. I've tried three different keys so I don't think that's it, and I've tried a little lubrication with no luck. Any suggestions?

Thanks

D. Goodwin