1978 C10 Electrically Dead

[clockdoc]

Since my first post about a leaking windshield, I've been driving my "new" truck (1978 C10 shortbed/305 V8) and making minor improvements as convenient. Today, I pulled the truck into the garage to install a new radio, cut it off and, a little later tried to restart it. It cranked but didn't start. Tried again and it turned a few revolutions and went dead. Investigation indicates that the fuse panel has no incoming power. I have no lights, horn, radio, etc. Nothing!

I have a Chilton's and a Haynes. Neither has an overall wiring diagram. I'm suspecting a fusible link. Do any of you have any other ideas?

I'll really appreciate any suggestions.