Here is a classic example from my own experience. One day early in my career, I was called out to service a walk-in cooler where the interior light was not working. Upon arrival, I jumped right into the repair. I already decided that the problem must be a loose wire or burned-off terminal.

Since the light fixture itself was a little difficult to get to, I decided to check the supply voltage coming into the cooler and then work my way to the light fixture. At each junction I found no problem. There were no breaks in the electrical connection and voltage was present at each point. I spent 45 minutes looking for the electrical disconnect, opening electrical boxes, checking the wiring and voltage supply.

I was becoming frustrated and decided to take a 10-minute break and rethink the problem. As I was walking back into the cooler, I spotted the maintenance person and asked how long the light was out and if he had noticed anything strange when he changed the bulb.

That is when he told me he never tried changing the bulb.

When I heard this, my mouth dropped open. Could it simply have been the light bulb?

Sure enough, that was the problem — a burned-out light bulb. If I had tried the light bulb in the first place, I would have finished the job in one minute, instead of wasting almost an hour looking for something major.

After that day, I decided never to overlook the obvious. I always check for the obvious problem and speak with the customer to get a history of the system before starting any troubleshooting.

It was a lesson well learned.

Marchese is owner of Coldtronics of Pittsburgh. He can be reached at 412-734-4433, www.coldtronics.com, or joe@coldtronics.com.

Publication date: 06/02/2003