Basic Troubleshooting Strategies

A new residential neighborhood is being built, and you are working as a member of the construction crew. One day, when the heating technicians are on-site doing checks of the gas furnaces in each new house, they report that the last house in the neighborhood does not have natural gas. The piping is installed, of course, but when they turn the gas valve on nothing comes out.

The gas pipeline servicing these houses is laid out in the following manner:

Each black dot on the diagram is a shutoff valve, used for isolating different sections of the service pipeline. Based on the heating technician’s report, you conclude that the service pipeline going up to that house must not be “live,” and that one of the numbered valves was probably left in the off position. But which one could it be?

You know that the main utility connection at the street is “live,” because the gas heater in the contractor mobile building is working just fine. You decide to go to valve #8 and check for gas pressure at that point in the pipeline with a portable pressure gauge, then checking the pressure at each valve location down the pipeline until you find where there is good gas pressure. However, before you step out of the room to go do this, one of your co-workers suggests you start your search at the middle point of the pipeline instead: at the location of valve #4.

Explain why your co-worker’s idea is better, and also what your next step would be if: (a) you did find pressure at that point, and (b) if you did not find pressure at that point.

As a technician, you are sent to troubleshoot a complex piece of electronic equipment that has stopped working. Upon opening the cabinet door for this equipment, your nose is greeted by the pungent odor of burnt circuit board (a smell you are unlikely to forget, once having experienced it). What does this simple fact indicate (or possibly indicate) about the nature of the equipment’s fault?

Two computer technicians are called to troubleshoot malfunctioning computer systems. Although the symptoms in each system are very similar, the histories of the two systems are not. The first computer is a unit that has been in operation for over two years, while the second system is a brand-new prototype, still in the developmental stages.

Without knowing any more details on these two computer systems, what recommendations can you give to the two technicians about to troubleshoot them? If you were asked to troubleshoot each system, how would you approach the two systems differently? What ranges of problems might you expect from each system?