Not sure if this is the sort of thing you mean, since it was only a fault-finding thing, but the constraints were _very_ tight... A long time ago I was Mister

Not sure if this is the sort of thing you mean, since it was only a fault-finding thing, but the constraints were _very_ tight... A long time ago I was Mister Fix-it for a company that made top-of-the-line lighting desks for touring rock bands. If your band wasn't touring with one of their desks you hadn't yet made it. The company developed a new desk and sold the first couple. Then one band said they had an intermittent problem during rehearsals where the desk would just stop making the lights go. I got sent to fix it. Couldn't find anything, and couldn't make it break. First show of the tour, 15,000 people in the audience, the house lights have gone down, the intro tape is running and the guy on the desk announces that it's stopped working! I ran backstage to get my tools to open the desk (god knows why I'd left them there), pelted back to the desk, and on the way I realised what must be going wrong. It must have been the adrenalin that heightened the thought processes. Opened the desk, moved the component that I'd worked out was shorting to ground and causing the output to stop, and he was back in business before the intro tape had finished. I still get a bit of a high when I think about the total head rush of fixing that problem like that. The 'permanent' fix for him was a tiny piece of gaffer tape under the component. The permanent fix was to use the component the PCB was designed for rather than one someone had to hand with a different footprint.