From: bpope at wordstock.com (Bryan Pope) Well, now that you mention it... It's probably been several years since I bored everyone with this story. Way back when I was in college a large electronics company donated an old hybrid computer. I was the only person on campus who had much interest in it, so I started working to get it up and running. I started with the analog computer, and things seemed to go pretty well. But there was one problem. It would never switch from initial condition mode to operate mode. So I'm sitting there pouring over the schematics trying to figure out what could be wrong, when it hit me, and I sat there saying, "no, they didn't." I had realized that one of the indicator lamps had burned out, but I figured that'd be something I'd worry about once it was up and running. But they used the voltage drop across the bulb as a pull-up. So the computer literally did not operate because of a burned out light bulb. When I replaced the bulb, it worked just fine. BLS