'83 Ignition Switch/Key Cylinder Woes

[Bob Q]

I went to start my '83 K2500 this afternoon and when I turned the key to the Start position, I heard and felt a "pop" and then the starter didn't engage. Now, the key "clocking" is off and the it won't return all the way to Lock and it won't engage the starter either. The steering wheel is free though and not locked. I had noticed the key cylinder was getting a little stiffer when turning it in the Start position for a little while now, but I was a little slow on addressing it...now I have no choice. Does this sound like the rack and sector gear on the rod have broken or maybe the ignition switch on top of the column? This is a non-tilt column on an '83 with a manual transmission.

Thanks.