On the monitor call, I actually went on site, because she described everything as normal. I thought maybe the high voltage power supply, deflection board or tube had just failed. Took all of 2 minutes to figure it out. At that time, my first hour labor rate was $180.00.
On an unrelated call, I was told a client's film processor was developing blanks. (No image). On film processors, you develop film in chemicals - first with developer, then fix, wash and dry. We're talking about a $7000 processor. This client had switched the developer and fix chemicals, so they were fixing the film before they developed it - so of course it was blank. The tricky part, after figuring out what happened, was how to tell the client what they did - with some tact.