Dodge Repair: 1979 Dodge Power Wagon: no start

Question
My 1979 dodge powerwagon W200(4wd) will not start from key. all power from the key is gone. To add to everything there is no spark what so ever. Do you hve any ideas why this might be?

Answer
Hi Graham,
I am unclear what you mean by "all power from key is gone" but then you say "no spark what so ever". The if the ignition switch had no power output on any of its circuits I would not expect there to be spark, nor would I expect there to be any spark. What does work, and what doesn't?
I don't have a wiring diagram so will be limited in what I can suggest, but let me know.
Roland